Hemet City Council
September 10, 2024

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 223 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
TMDL Constituent Waterbody Existing Limitation New Limitation Sediment in Newport Bay/San Diego Creek Watershed Sediment
Newport Bay 2,500 tons/year No Change
San Diego
Creek and its
Tributaries
2,500 tons/year No Change
Organochlorine Compounds in
San Diego Creek, Upper and Lower Newport Bay
Total DDT
San Diego
Creek and
Tributaries
128.3 g/year No Change
Upper
Newport Bay 51.8 g/year No Change
Lower
Newport Bay 19.1 g/year No Change
Rhine
Channel 0.7 g/year No Change
Chlordane
Upper
Newport Bay 30.1 g/year No Change
Lower
Newport Bay 11.0 g/year No Change
Rhine
Channel 0.1 g/year No Change
Total PCBs
Upper
Newport Bay 29.8 g/year No Change
Lower
Newport Bay 78.1 g/year No Change
Rhine
Channel 4.1 g/year No Change
Dieldrin
San Diego
Creek and
Tributaries
183.4 g/year No Change
Lower
Newport Bay 4.45 g/year No Change
Rhine
Channel 0.13 g/year No Change
Toxaphene
San Diego
Creek and
Tributaries

1.9 g/year No Change
Diazinon &
Chlorpyrifos
in San Diego
Creek and
Upper
Newport Bay
Chlorpyrifos
Upper
Newport Bay
18 ng/L Acute No Change

8.1 ng/L Chronic No Change
San Diego
Creek
18 ng/L Acute No Change

12.6 ng/L Chronic No Change
Diazinon San Diego 72 ng/L Acute No Change

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 224 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
TMDL Constituent Waterbody Existing Limitation New Limitation Creek 45 ng/L Chronic No Change
Toxic Pollutants (Metals) in San Diego Creek and Newport Bay Cadmium
Upper
Newport Bay
9,589 lbs/year No Change
42 µg/L Acute No Change

9.3 µg/L Chronic No Change
San Diego
Creek
Acute 42 (µg/L)
Chronic 9.3 (µg/L)
No Change
Chromium Rhine
Channel 5.66 kg/year No Change
Copper
Newport Bay
3,043 lbs/year
No change, until
superseded upon the
effective date of the
Copper TMDLs for
Newport Bay adopted
through Resolution
R8-2022-0012

4.8 µg/L Acute No change

3.1 µg/L Chronic No change
San Diego
Creek See Appendix 7, Table 7.2 No Change
Lead
Newport Bay
17,638 lbs/year No Change
210 µg/L Acute No Change

8.1µg/L Chronic No Change
San Diego
Creek See Appendix 7, Table 7.3 No Change
Mercury Rhine
Channel 0.0171 kg/year No Change
Zinc
Newport Bay
174,057 lbs/year No Change
90 µg/L Acute No Change
81 µg/L Chronic No Change
San Diego
Creek See Appendix 7, Table 7.4 No Change
Metals in San Gabriel River and
Impaired tributaries
Copper Coyote
Creek

0.941 kg/day Dry Weather No Change

9.41 kg/day Wet Weather
Load Capacity
Formula (Previous
designation assumed
flow was equal to 156
cfs)
Lead Coyote
Creek 36.9 kg/day Wet Weather
Load Capacity
Formula (Previous
designation assumed
flow was equal to 156
cfs)
Zinc Coyote
Creek 55 kg/day Wet Weather Load Capacity Formula (Previous

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 225 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
TMDL Constituent Waterbody Existing Limitation New Limitation designation assumed
flow was equal to 156
cfs)
Freshwater, Newport Bay
Watershed Selenium
Selenium
Tissue-based
Water Column
San Diego
Creek None
10 µg/L in
accordance with R8-
2017-0014
Santa AnaDelhi
Channel
None
11 µg/L in
accordance with R8-
2017-0014
Big Canyon
Wash None 1 µg/L in accordance with R8-2017-0014
Selenium
CTR-based
Water Column
(at Costa
Mesa
Channel)
None 5 µg/L in accordance
with R8-2017-0014
Copper in Upper and
Lower Newport Bay
Dissolved
Copper Newport Bay
3,043 lbs/year (from
USEPA’s Toxic Pollutants
[Metals] in San Diego Creek
and Newport Bay TMDL)
2,501 lbs/year (upon
effective date of
Copper TMDLs)

4.8 µg/L acute (from
USEPA’s Toxic Pollutants
TMDL)
No Change

3.1 µg/L chronic (from
USEPA’s Toxic Pollutants
TMDL)
No Change

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 226 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Table D.3 - Summary of Changes to Effluent Limitations in Order R8-2010-0033 TMDL Constituent Waterbody
Existing
Limitation New Limitation
Middle Santa Ana River Watershed
Fecal Coliform
Dry Season
Santa Ana River
180 organisms/
100 ml w/ 10% not
> 360 organisms/
100 ml
Not included, as
superseded per
the terms of the
MSAR Bacteria
TMDL
Fecal Coliform
Wet Season
180 organisms/
100 ml w/ 10% not
> 360 organisms/
100 ml
Not included, as
superseded per
the terms of the
MSAR Bacteria
TMDL
E. Coli
Dry Season
113 organisms/
100 ml w/ 10% not
> 212 organisms/
100 ml
Comprehensive
Bacterial
Reduction Plan
No Change
E. Coli Wet
Season
113 organisms/
100 ml w/ 10% not
> 212 organisms/
100 ml
Comprehensive
Bacterial
Reduction Plan
No change, but
high flow
suspension added
in accordance with
R8-2012-0001
Lake Elsinore/
Canyon Lake TMDL
Nutrients Canyon Lake
Total Phosphorus
306 kg/yr
CNRP
No Change
Total Nitrogen
3,974 kg/yr
CNRP

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 227 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Lake Elsinore
Total Phosphorus
124 kg/yr
CNRP
Total Nitrogen
349 kg/yr
CNRP
Table D.4 - Summary of Changes to Effluent Limitations in Order R8-2010-0036 TMDL Constituent Waterbody
Existing
Limitation New Limitation
Big Bear Lake Dry
Hydrological
Conditions
Total Phosphorus Big Bear Lake Total Phosphorus
475 Ibs/yr No Change

2. General Principles of Law Governing Anti-Backsliding Analysis for Effluent Limitations Established Pursuant to TMDLs
There are both statutory anti-backsliding provisions in CWA section 402(o) and regulatory anti-backsliding provisions in 40 CFR section 122.44(l). The CWA’s statutory prohibition against backsliding applies under a narrow set of criteria specified in section 402(o). (See State Water Board Order WQ 2015-0075 at pp. 19-23; NPDES Permit Writers’ Handbook at § 7.2.1.1 (USEPA 2010).)
Section 402(o)(1) prohibits relaxing technology-based effluent limitations originally established based on best professional judgment (BPJ), when there is a newly revised effluent limitation guideline. This section is inapplicable here since none of the WQBELs in the Order are technology based effluent limitations (TBELs) based on BPJ.

Section 402(o)(1) also prohibits relaxing of WQBELs imposed pursuant to CWA sections 301(b)(1)(C) or 303(d) or (e). CWA section 301(b)(1)(C) requires the permitting authority to include effluent limitations “necessary to meet water quality standards, treatment standards, or schedules of compliance” established by federal or state laws and regulations. Clean Water Act section 303(d)-(e) requires inclusion of effluent limitations for those pollutants for which TMDLs have been established. However, backsliding may be allowed for these categories of WQBELs pursuant to one of six exceptions in CWA section 402(o)(2). Exceptions include when:
· There have been material and substantial alternations or additions to the permitted facility that justify the relaxation;
· New information (other than revised regulations, guidance, or test methods) is available that was not available at the time of permit issuance and that would have

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 228 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
justified a less stringent effluent limitation. If the effluent limitation was based on water quality standards, any changes must result in a decrease in pollutants discharged; · Technical mistakes or mistaken interpretations of the law were made in issuing the permit under CWA section 402(a)(1)(b);
· Good cause exists because of events beyond the permittee’s control (e.g., natural disasters) and for which there is no reasonably available remedy; · The permit has been modified under CWA sections 301(c), 301(g), 301(h), 310(i), 301(k), 301(n), or 316(a);
· The permittee has installed and properly operated and maintained required treatment facilities but still has been unable to meet the effluent limitations (relaxation may be allowed only to the treatment levels actually achieved).

Relaxation of WQBELs may also be allowed if such backsliding is consistent with the provisions in CWA section 303(d)(4). CWA section 303(d)(4) speaks to backsliding under two different circumstances: for non-attainment and attainment receiving waters. First, when the receiving waterbody has been identified as not meeting applicable water quality standards (i.e., a nonattainment water), CWA section 303(d)(4)(A) allows the establishment of a less stringent effluent limitation if two conditions are met: (a) the existing effluent limitation was based on a TMDL or other WLA established under CWA section 303, and (b) the attainment of water quality standards will be assured or the designated use not being attained is removed in accordance with the water quality standards regulations. 34 (NPDES Permit Writers’ Manual, § 7.2.1.3 (USEPA 2010); 33 USC § 1313(d)(4)(A).) Second, when the receiving waters quality equals or exceeds levels necessary to protect beneficial uses or otherwise meets applicable water quality standards (i.e., an attainment water), CWA section 303(d)(4)(B) provides that an effluent limitation based on a TMDL, WLA, other water quality standard, or any other permitting standard, may only be relaxed where the action is consistent with state’s antidegradation policy. (NPDES Permit Writers’ Manual, § 7.2.1.3 (USEPA 2010); 33 USC § 1313(d)(4)(B).) In the Order, all WQBELs are imposed pursuant to CWA section 303(d) based on TMDL WLAs, as enumerated in Appendices 2 through 13. For purposes of the following analysis, both sections 303(d)(4) and the exceptions in section 402(o)(2) are relevant. “[US]EPA has consistently interpreted CWA section 402(o)(1) to allow relaxation of WQBELs and effluent limitations based on state standards if the relaxation is consistent with the provisions of CWA section 303(d)(4) or if the exceptions in CWA section 402(o)(2) apply.

The two provisions [303(d)(4) and 402(o)(2)] constitute independent exceptions to the prohibition against relaxation of effluent limitations. If either is met, relaxation is permissible.” (NPDES Permit Writers’ Manual, § 7.2.1.3 (USEPA 2010).) As set forth below, the changes to numeric WQBELs in the Order either do not constitute backsliding or satisfy one or more of the foregoing exceptions to anti-backsliding as described below. 34 This subsection does not provide an exception for establishing less stringent limitations where the original limitation was based on state permitting standards (e.g., state treatment standards) and was not based on a TMDL or WLA.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 229 of 320 Fact Sheet
Santa Ana Regional MS4 Permit

3. WQBEL Revisions That Do Not Constitute Backsliding
(a) Bacterial Indicators in Newport Bay for the SHEL Beneficial Use (Appendix 2) The 2009 Orange County MS4 Permit incorporates WQBELs consistent with the assumptions and requirements of the Fecal Coliform TMDLs for Newport Bay to protect the REC-1 and SHEL beneficial uses. However, since the adoption of that permit, the TMDLs have been amended twice to extend the attainment deadline for meeting the SHEL water quality objectives and WLAs. The Santa Ana Water Board approved the first amendment on June 16, 2017 through Resolution No. R8-2017- 0019, which was subsequently approved by the State Water Board and Office of Administrative Law. The amendment extended the attainment deadline from December 30, 2019 to December 31, 2022. The Santa Ana Water Board approved a second amendment on June 3, 2022 through Resolution No. R8-2022-0017, which was subsequently approved by the State Water Board on November 15, 2022 and the Office of Administrative Law on June 15, 2023. The amendment extended the attainment deadline from December 31, 2022 to December 31, 2030.

The Order updates the WQBEL in Appendix 2 with the new compliance deadline for SHEL consistent with the assumptions and requirements of the 2017 and 2022 revisions to the Fecal Coliform TMDLs for Newport Bay. The numeric density limitation remains unchanged from the last permit and is based on the same water quality objective; accordingly, the WQBEL for SHEL is just as stringent as in the prior permit, only with a longer compliance timeframe.

Even if the change described above is subject to the CWA’s anti-backsliding provisions, the revision complies with CWA section 304(d)(4)(A). Section 303(d)(4)(A) of the CWA allows relaxation of effluent limits in non-attainment waters if “the cumulative effect of all such revised effluent limitations based on such total maximum daily load or waste load allocation will assure the attainment of such water quality standard, or (ii) the designated use which is not being attained is removed in accordance with regulations” established under the CWA. Here, the compliance deadline was adjusted, as reflected in the revised TMDL. Compliance with the WQBEL will therefore continue to assure the attainment of the water quality objectives for SHEL in Newport Bay within a reasonable time frame set forth in the revised implementation schedule.
(b) Toxic Pollutants (Metals) in San Diego Creek and Newport Bay (Appendix 7) and Copper in Upper and Lower Newport Bay (Appendix 10) The WQBELs for dissolved copper discharges from MS4s to Newport Bay contained in Appendix 7 are consistent with the assumptions and requirements of the Toxic Pollutants (Metals) in San Diego Creek and Newport Bay TMDL (Toxics TMDLs) adopted by USEPA. These WQBELs remain unchanged from the 2009 Orange County MS4 Permit, except that they will be superseded by the WQBELs for dissolved copper contained in Appendix 10 upon the effective date of the TMDLs for Copper in Upper and Lower Newport Bay (Copper TMDLs), adopted through Santa Ana Water Board Resolution No. R8-2022-0012. The Copper TMDLs will not become effective unless and until approved by the State Water Board and USEPA.

The WQBELs for all other metals and the WQBELs for copper discharges to San

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 230 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Diego Creek in Appendix 7 remain effective and unchanged by adoption of the Copper TMDLs.

The Copper TMDLs retain as WQBELs the concentration-based loading capacity values based on the CTR saltwater criteria for dissolved copper (4.8 µg/L acute and

3.1 µg/L chronic) from USEPA’s Toxics TMDLs. However, the Copper TMDLs would revise the mass-based WLA for MS4 discharges to Newport Bay based on updated data. In USEPA’s Toxics TMDLs, mass-based loads for dissolved metals are based on available data from prior to 2002 and used a 20% margin of safety. The WQBEL for mass-based discharges of dissolved copper from MS4s to Newport Bay is 3,043 lbs/year in Appendix 7. The revised mass-based WLA from the Copper TMDLs uses data obtained from after 2002 and a 10% margin of safety. Appendix 10 would implement a WQBEL for mass-based discharges of dissolved copper from MS4s to Newport Bay of 2,501 lbs/year. Since the WQBELs for dissolved copper discharges to Newport Bay from MS4s in Appendix 10 are either at least as stringent or more stringent than the WQBELs in Appendix 7, there will be no backsliding once the WQBELs in Appendix 10 take effect.
(c) Metals in San Gabriel River and Impaired Tributaries (Appendix 8) The 2009 Orange County MS4 Permit incorporates WQBELs consistent with the assumptions and requirements of the San Gabriel River and Impaired Tributaries TMDL for Metals, which was adopted by USEPA on March 26, 2007. The massbased WQBELs for wet weather discharges of Copper, Lead and Zinc from MS4s to Coyote Creek were set at 9.41 kg/day, 36.9 kg/day, 55 kg/day, respectively. These values were calculated using the load capacity formula specified in the TMDL assuming a flow equal to 156 cfs. Given the variable amount of flow during wet weather in Orange County, the Order removes the assumption concerning flow during wet weather and instead directs the Permittees to calculate the maximum daily mass loads based on the formulas specified in the TMDL. The mass-based WQBELs for wet weather in Appendix 8 are therefore not any less stringent than those included in the prior order and not subject to the CWA’s anti-backsliding provisions.

4. WQBEL Revisions that Fall Within an Exception to Backsliding (a) Bacterial Indicators in Middle Santa Ana River Bacteria (Appendix 11) The 2009 Orange County MS4 Permit incorporates WQBELs consistent with the assumptions and requirements of the Bacterial Indicator TMDLs for Middle Santa Ana River Watershed (MSAR Bacteria TMDL). The Order in Appendix 11 removes the WQBELs for fecal coliform for both dry weather condition and wet weather conditions included in the prior permit, as well as adds a provision for high flow suspension during wet weather conditions.

The removal of WQBELs for fecal coliform under dry and wet weather conditions from Appendix 11 is based on Footnote C of Table 6-1x of the MSAR Bacteria TMDL and the State Water Board’s approval of Part 3: Bacteria Provisions and Variance Policy of the ISWEBE. While Table 6-1x of the MSAR Bacteria TMDL includes fecal coliform WLAs for both dry and wet weather, Footnote C to the table provides: “The fecal coliform TMDLs, WLAs and LAs become ineffective upon the replacement of

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 231 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
the REC1 fecal coliform objectives in the Basin Plan by approved REC1 objectives based on E. coli.” In 2018, the State Water Board adopted statewide water quality objectives for REC-1 with E. coli as the sole freshwater bacterial indicator. These objectives became effective on February 4, 2019 and supersede the bacteria water quality objectives for REC-1 in the Santa Ana Water Board’s Basin Plan.

The addition of a high flow suspension provision to the wet weather WQBELs in Appendix 11 is pursuant to the Basin Plan amendment adopted through Resolution No. R8-2012-0001, which became effective April 8, 2015. The suspension is premised on the fact that recreational use of the receiving waters at issue is precluded under certain flow conditions that make recreational activities unsafe.

Because the REC-1 beneficial use is not attained during periods of high flow, the high flow suspension provision was added to remove this beneficial use under those conditions. This update to the Basin Plan is reflected in the revised WQBELs in Appendix 11.

These revisions comply with the exception to backsliding found in CWA section 304(d)(4)(A). Section 303(d)(4)(A) of the CWA allows relaxation of effluent limits in non-attainment waters if “the cumulative effect of all such revised effluent limitations based on such total maximum daily load or waste load allocation will assure the attainment of such water quality standard, or (ii) the designated use which is not being attained is removed in accordance with regulations” established under the CWA. Here, E. coli continues to serve as a bacteria indicator to assure the attainment of the water quality objectives for REC-1 pursuant to the express terms of the MSAR Bacteria TMDL. Additionally, because the REC-1 beneficial use is not attained during periods of high flow, and the high flow suspension provision was added pursuant to the regulatory process through a Basin Plan amendment, the addition of the high flow suspension provision to the wet weather WQBELs falls within the CWA section 303(d)(4)(A) to backsliding.

I. Plain Language
Government Code section 6219(a) states that “Each department, commission, office, or other administrative agency of state government shall write each document that it produces in plain, straightforward language, avoiding technical terms as much as possible, and using a coherent and easily readable style.” This requirement is more commonly known as the State’s “plain language requirement.” The Order and this Fact Sheet have been prepared with careful consideration of the plain language requirement.

There are a variety of indicators for measuring the “readability” of a document. These indicators include the Flesch Kincaid Reading Ease, Flesch Kincaid Grade Level, and the Gunning Fog Score. These first two indicators are widely available in common wordprocessing software and were applied to the Order and Fact Sheet. The results indicate that a person that has achieved a college junior level of education should be able to readily understand these documents. Given the technical and legal subject matter, the readability of the Order and this Fact Sheet is appropriate and satisfies the State plain language requirement.

J. Other Regulations, Plans, and Policies

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 232 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
The Order implements all other applicable federal regulations and state regulations, plans, and policies.

The Order is consistent with numerous State Water Board decisions, including Order WQ2000-11 (Cities of Bellflower, et al., the City of Arcadia, and Western States Petroleum Association), Order WQ 2001-15 (Building Industry Association of San Diego County and Western States Petroleum Association), Order WQO 2002-0014 (City of Aliso Viejo, City of Mission Veijo, Golden Rain Foundation of Laguna Woods [aka Leisure World]), Order WQ 2015-0075 (Waste Discharge Requirements for Municipal Separate Storm Sewer System [MS4] Discharges within the Coastal Watersheds of Los Angeles County, Except those Discharges Originating from the City of Long Beach MS4), and Order WQ 2020- 0038 (Approval of Watershed Management Programs and an Enhanced Watershed Management Program submitted pursuant to Los Angeles Water Quality Control Board Order R4-2012-0175).

K. Human Right to Water
The Order is consistent with the State Water Board Resolution’s No. 2016-0010, which adopts the human right to water as a core value and directs its implementation in programs and activities. Resolution No. R8-2019-0078 affirms the Santa Ana Water Board’s commitment to implementing the human right to water in its programs and activities, including permitting activities. The Order is expected to positively impact the human right to water through positively impacting water quality in the Santa Ana Region, including waters designated for municipal or domestic supply (MUN). Even waterbodies within the region not designated as MUN may nevertheless be used for drinking, cooking or sanitation purposes. Consequently, while this Order does not require Permittees to attain criteria intended to protect MUN in waterbodies without that designation, any positive impact to water quality also supports the human right to water.

L. Assembly Bill 2108
The Order is consistent with Assembly Bill 2108. Section XXIII.B of this Fact Sheet describes the Bill and actions taken to comply in detail.

V. RATIONALE FOR PERMITTEE RESPONSIBILITIES
A. Permittee Responsibilities
Sections III.A and III.B of the Order establish the basic responsibilities of all the Permittees, including the Principal Permittees. These sections are designed to require implementation of the “iterative process.” This process includes planning and documentation of program activities, execution, tracking of outcomes, and evaluation through comparison with performance metrics. The goal is continual improvement of the Permittees’ control measures, projects, and programs to attain receiving water limitations (section VI) and effluent limitations (section VII) whose final compliance deadlines have not passed or where no final compliance deadline is specified, effectively prohibit non-stormwater discharges (section IV), and reduce pollution to the maximum extent practicable. These requirements are included in this Order pursuant to CWA section 402(p)(3)(B)(iii) which, in part, requires controls to reduce

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 233 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
the discharge of pollutants to the maximum extent practicable and allows the state to include such other provisions determined appropriate for the control of pollutants.

These sections also describe the basic responsibilities for internal and external coordination within and among the Permittees respectively according to 40 CFR sections 122.26(d)(2)(i)(D) and (d)(2)(iv). These sections require maintenance of records and the submission of reports that are adequate to determine compliance.

B. Implementation Agreement
Section III.C of the Order requires that the Permittees have inter-agency and inter-Permittee agreements that are necessary to satisfy the requirements of the Order. Various such agreements have been reported to exist to carry out certain programs, such as the Sanitary Sewer Overflow Program. Some agreements may need to be reviewed and updated to comply with the Order. Section III.C is supported by 40 CFR section 122.26(d)(2)(i), which recognizes that a “series of contracts” may be necessary to comply with an MS4 permit; and by 40 CFR section 122.26(d)(2)(i)(D), which requires “interagency agreements among coapplicants” for MS4 permit coverage.

C. Legal Authority/Enforcement
Section III.D. of the Order largely continues requirements that the Permittees secure and maintain the legal authority to control the discharge of pollutants according to the requirements of the Order. In short, 40 CFR section 122.26(d)(2)(i) requires applicants for MS4 discharge permits to demonstrate adequate legal authority that enables them to: control the contribution of pollutants from industrial activity; prohibit illicit discharges; control spills, dumping, or disposal of materials other than stormwater; control the contribution of pollutants between MS4s through interagency agreements; require compliance with ordinances, permits, contracts, or orders; and carry out inspection, surveillance, and monitoring procedures necessary to determine compliance. Section III.D is intended to support the requirements of 40 CFR section 122.26(d)(2)(i).

The Order describes requirements but does not grant the Permittees any legal authorities that may be necessary to comply. The Permittees typically secure this authority through their municipal ordinances. All the Permittees have reported adopting model water quality ordinances to comply with prior orders. These water quality ordinances include measures to enforce compliance through inspections and sanctions if necessary.

The Order requires the Permittees to impose a series of effective, progressive actions to compel compliance with regulatory requirements related to the control of discharges of pollutants to their MS4s. The Order adds new requirements for the Permittees to track and evaluate challenges to their authority. Where a challenge results in an adverse judgment in a court of law, the Permittees must report it along with a plan to make their authority adequate.

D. Notification Requirements
Requirements to report a release or threatened release of pollutants within the Permittees’ jurisdiction that poses an imminent threat to human health or the environment are consistent with requirements in Water Code section 13271 and Health and Safety Code section 5411.5.

These are carried over from prior permits.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 234 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
The Order also includes requirements to report bi-annually facilities known or suspected of not having authorization to discharge waste under an NPDES stormwater permit, as well as facilities with known, suspected or threatened violations of stormwater permits such as the Industrial General Permit, Construction General Permit, and Scrap Metal Permit. These requirements are part of progressive enforcement, which includes procedures to coordinate enforcement between the Santa Ana Water Board and Permittees and are consistent with the provisions of Senate Bill 205 (2019) and Water Code section 13383.10.

E. Fiscal Analysis
40 CFR section 122.26(d)(2)(vi) requires, for each fiscal year to be covered by the permit, a fiscal analysis of the necessary capital and operation and maintenance expenditures necessary to accomplish the activities of the stormwater management program, including the monitoring program. The analysis is to include a description of the source(s) of funds that are proposed to meet the necessary expenditures, including legal restrictions on the use of such funds. Additionally, 40 CFR section 122.42(c)(5) requires that annual reports for MS4 permits include annual expenditures and budget for the year following each Annual Progress Report.

The inclusion of the requirement to perform a fiscal analysis annually in the Order was carried over from the previous permits. A requirement has been added so that fiscal reports conform to USEPA or State reporting guidance, when such guidance becomes available.

F. Special Studies
It is encouraged that Permittees consider conducting special studies. The requirement for special studies workplans derives from Water Code section 13385. The results of these studies may support future Basin Plan amendments to revise TMDLs and/or water quality standards. Special studies include projects intended to contribute to stormwater science or to support continual improvement of the Permittees’ stormwater program. Special studies do not include projects intended to assess compliance with receiving water limitations or water quality-based effluent limitations.

VI. RATIONALE FOR DISCHARGE PROHIBITIONS
A. Non-Stormwater Discharge Prohibitions
Consistent with federal law, section IV of the Order prohibits non-stormwater discharges to the MS4, where such discharges are not authorized by a separate permit or otherwise authorized or conditionally exempt. CWA section 402(p)(3)(B)(ii) forms the basis of this requirement, which provides that MS4 permits “shall include a requirement to effectively prohibit non-stormwater discharges into the storm sewers.” (CWA § 402(p)(3)(B)(ii-iii); see also 40 CFR § 122.26(d)(2)(i)(B).)
USEPA adopted implementing regulations for the effective prohibition on nonstormwater discharges to the MS4 found at 40 CFR section 122.26. In its 1990 preamble to these regulations, USEPA noted that it was “clarifying that section 402(p)(3)(B) of the CWA (which requires permits for municipal separate storm sewers to ‘effectively’ prohibit non-storm water discharges) does not require permits for municipalities to prohibit certain discharges or flows of non-storm water to waters of the United States through municipal separate storm sewers in all cases.” (55 FR 47990-01, 48037 [emphasis added].) Accordingly, federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(1) state that the following non-stormwater discharges may be allowed if they are not determined

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 235 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
to be a significant source of pollutants to the MS4: water line flushing, landscape irrigation, diverted stream flows, rising ground waters, uncontaminated groundwater infiltration, uncontaminated pumped groundwater, discharges potable water sources, foundation drains, air conditioning condensation, irrigation water, springs, water from crawl space pumps, footing drains, lawn watering, individual residential car washing, flows from riparian habitats and wetlands, dechlorinated swimming pool discharges, street wash water, and firefighting flows. If, however, these discharges are determined to be a significant source of pollution then they must be prohibited. Additionally, the MS4 permit may include permit conditions that require municipalities “otherwise control any of these types of discharges where appropriate.” (55 FR 47990-01, 48037.) Section IV.A.2 of the Order largely carries over provisions from previous permits by exempting a limited number of authorized and conditionally exempt non-stormwater discharges from the non-stormwater discharge prohibition. Table 3 contains a list of authorized categories of non-stormwater discharges that are presumed not to be a significant source of pollutants, which is primarily compromised of the categories listed in 40 CFR section 122.26(d)(2)(iv)(B)(1). Three conditional exemptions for nonstormwater discharges have been added to the Order. Additionally, the Order removes certain fee exemptions contained in prior permits. These changes are described in greater detail below.

1. Conditional Exemption for CERCLA Authorized Discharges The Order adds a conditional discharge authorization for temporary non-stormwater discharges authorized pursuant to sections 104(a) or 104(b) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). These discharges typically consist of short-term, high-volume discharges from groundwater extraction well development or redevelopment or from state-required testing of potable water treatment plants and occur as part of USEPA-authorized groundwater remediation action under CERCLA. Such discharges must either: (i) comply with water quality standards as applicable or relevant and appropriate requirements (“ARARs”) under section 121(d)(2) of CERCLA; or (ii) be subject to either (a) a written waiver of ARARs pursuant to section 121(d)(4) of CERCLA or (b) a written determination that compliance with ARARs is not practicable considering the exigencies of the situation pursuant to 40 CFR section 300.415(j). Because ARARs implement state water quality standards when a permitting action is superseded by federal law under CERCLA, a conditional discharge authorization is appropriate in the Order.

2. Conditional Exemption for Non-Emergency Firefighting Flows The Order also adds a conditional exemption for discharges from essential nonemergency firefighting activities, provided appropriate BMPs are implemented to reduce pollutants. The BMPs must be based on the California Department of Forestry and Fire Protection, Office of the State Fire Marshal’s Water-Based Fire Protection Systems Discharge Best Management Practices Manual (September 2011) for water-based fire protection system discharges, or equivalent BMP manual for fire training activities and post-emergency firefighting activities. Firefighting activities are listed in 40 CFR section 122.26(d)(2)(iv)(B)(1) for exclusion from the non-stormwater discharge prohibition and similarly excluded from the definition of “illicit discharge” in 40 CFR section 122.26(b)(2). USEPA has noted in its preamble

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 236 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
to the federal regulations that BMPs can be appropriate requirements for firefighting discharges: “In the case of fire fighting it is not the intention of these rules to prohibit in any circumstances the protection of life and public or private property through the use of water or other fire retardants that flow into separate storm sewers. However, there may be instances where specified management practices are appropriate where these flows do occur (controlled blazes are one example).” (55 FR 47990-01, 48037.) Accordingly, the Santa Ana Water Board finds that the requirement to implement BMPs during non-essential firefighting activities is appropriate in the Order.

3. Conditional Exemption for Irrigation Water
The Santa Ana Water Board has placed conditions on the discharge of irrigation water. Discharge is only allowed if runoff due to potable landscape irrigation is minimized through the implementation of an ordinance specifying water efficient landscaping standards, as well as an outreach and education program focusing on water conservation and landscape water use efficiency. BMPs must be implemented to minimize runoff and prevent introduction of pollutants to the MS4 and receiving water, including landscape water use efficiency requirements for existing landscaping, use of drought tolerant, native vegetation, and the use of less toxic options for pest control and landscape management.

Irrigation water may transport pollutants, such as nutrients, pathogens, and pesticides to receiving waters. Reducing irrigation runoff will reduce wastes discharged to receiving waters. In addition, practices to reduce irrigation runoff may reduce concentrations of some wastes in dry weather runoff35 . Irrigation has also
been identified as playing a key role in mobilizing pollutants such as pesticides36.

Reducing residential irrigation runoff will reduce wastes discharging to receiving waters.

The requirement for water conservation BMPs to minimize any non-stormwater discharge of irrigation water is consistent with statewide efforts to reduce wasteful water uses. In 2021, Governor Newsom proclaimed a drought state of emergency for all counties in California, urging Californians to step up their water conservation efforts and encouraging the State Water Board to prohibit certain wasteful water uses. The State Water Board found that an emergency exists due to drought conditions and prohibited wasteful water uses (like refilling fountains without recirculating pumps, overwatering landscapes, watering grass within 48 hours of rainfall, etc.) in emergency regulations. The requirements in the Order are consistent with these statewide water conservation efforts.

4. Effective Prohibition of Street Wash Water
35 Irvine Ranch Water District and Municipal Water District of Orange County, “The Residential Runoff Reduction Study”, July 2004.
36 Haver, Darren L. and Fox, Angelia, March 2008. Mitigating Pesticide Runoff in Urbanized Environments, Final Report, SWRCB Agreement No. 04-013-558-0.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 237 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Street wash water is listed in 40 CFR 122.26(d)(2)(iv)(B)(1) among those discharges that are exempt from the requirement to be effectively prohibited unless found to be a significant source of pollutants.

In 1997, the City of Los Angeles submitted a report to the Los Angeles Water Board entitled, A Study of Pollutants Entering Storm Drains from Street and Sidewalk Washing Operations in Los Angeles, California. The City reported that street washing occurred in conjunction with general street and alleyway cleaning operations. These operations involve manual trash and debris removal and street sweeping as well as washing with a disinfecting solution. The operations are “essential to maintain public health and control nuisance odors caused by deposition of human waste” related to homeless encampments. The operation objectives are “to remove trash, disinfect, and deodorize targeted streets, alleys, and sidewalks.” The City of Los Angeles documented that street wash water contained fecal indicator bacteria at levels that were comparable to raw sewage. In some locations, the biological chemical demand of the wash water was up to 6 times higher than raw sewage. The wash solution was also found to be highly toxic, and that the toxicity decreased with time or distance after the solution was applied to the street.

The wash water also contained highly varied concentrations of metals. Many metals were found in trace amounts. But others, such as zinc, were found in concentrations that averaged 6,478 µg/L, with a maximum of 18,700 µg/L. For comparison, the USEPA benchmark value for zinc is 100 µg/L. A benchmark value is a value above which the pollutant presents a level that could potentially impair water quality.

The findings in the 1997 report indicate that street wash water is a source of pollutants to waters of the U.S. Subsequent to the 1997 report, authorizations of the MS4 permits in the Santa Ana Region did not include street wash water on a list of allowable non-stormwater discharge types. This Order continues the exclusion from prior orders.

This exclusion should not be interpreted as a prohibition on street washing, but rather on any discharge to the MS4 from that action. This exclusion means that, if a Permittee performs street washing, controls must be in place to prevent the wastewater from discharging into the MS4. Generally, sweeping should be used as an alternate control whenever possible and swept material should be disposed of in the trash. All trash, debris, and free-standing oil/grease spills/leaks (use absorbent material if necessary) should be removed from the area before washing. Whenever practicable, Permittees should collect and divert street and alley wash water from the Permittees’ street. Sidewalk cleaning activities should be diverted to the sanitary sewer or to landscaped areas for infiltration.

5. De Minimis/Drinking Water System Discharges and Construction General Permit Discharges
Past permits authorized certain non-stormwater discharges from de minimis waste streams and potable water systems subject to the limitations and prohibitions of Order No. R8-2020-0006, NPDES Permit No. CAG998001 (de minimis permit) and State Water Board Order WQ 2014-0194-DWQ, NPDES No. CAG140001. This had the effect of exempting the Permittees from enrolling in and paying the fees

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 238 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
associated with these permits. The Order removes these fee exemptions and requires the Permittees to follow the normal permitting process to obtain coverage for these types of discharges under the appropriate NPDES permits. However, the MS4 Permittees can request coverage under “Various Locations”. This enrollment feature could allow a Permittee to only submit for coverage once for multiple project discharges from various locations in their jurisdiction.

Similarly, past MS4 permits authorized the Permittees to discharge wastes in runoff from capital improvement projects subject to the limitations and prohibitions of the Construction General Permit without enrolling in and submitting the fees associated with that permit. This practice conflicts with the approach used by every other Regional Water Board in the State. The Order removes this fee exemption.

Permittees are required to follow the normal permitting process for their capital improvement projects to obtain coverage under the Construction General Permit.

Under earlier permits, the notification process for municipalities was different than all other types of construction dischargers. Permittees were not motivated by annual fees to submit Notices of Termination (NOTs) for their projects. This has made it challenging to monitor the installation of post-construction controls and site stabilization after construction for Permittee construction projects. Requiring Permittees to undergo the same processes as other construction projects will improve compliance monitoring.

B. Trash Discharge Prohibition
Section IV.B of the Order prohibits the discharge of trash to surface waters of the State and the deposition of trash where it may be discharged into surface waters of the State. This prohibition is added to the Order in compliance with the Amendment to the Water Quality Control Plan for Ocean Waters of California to Control Trash and Part 1 Trash Provisions of the Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (Trash Provisions), which became effective January 12, 2016. The Trash Provisions establish a water quality objective, a prohibition on the discharge of trash, and implementation requirements to control trash that must be included in MS4 permits. The prohibition is further consistent with federal regulations specifying that Permittees must include in their management program maintenance activities and a maintenance schedule for structural controls to reduce pollutants, specifically including “floatables,” in discharges from MS4s. (See 40 CFR § 122.26(d)(2)(iv)(A)(1).)
VII. RATIONALE FOR TRASH CONTROL PROVISIONS
Section V of the Order implements the prohibition on discharges of trash specified in section IV.B of the Order and the Trash Provisions adopted on April 7, 2015, by the State Water Board through Resolution No. 2015-0019.

Section V provides that each Permittee with regulatory authority over priority land uses, designated land uses, and/or equivalent alternate land uses must implement an effective program to reduce or eliminate the discharge of trash to ocean waters, inland surface waters, enclosed bays, estuaries, and along shorelines or adjacent areas in amounts that adversely affect beneficial uses or cause nuisance. Permittees shall comply with this requirement following one of two “tracks”.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 239 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Under Track 1, a Permittee must install, operate, and maintain full capture systems for storm drains that capture runoff from priority land uses in their respective jurisdictions. Under Track 2, a Permittee must install, operate, and maintain any combination of full capture systems, multi-benefit projects, treatment control measures and/or institutional control measures (i.e., the systems must achieve “full capture equivalency”).

Both compliance tracks focus trash control efforts on priority land use areas, which have been shown to generate a significant amount of trash and include high density residential, industrial, commercial, mixed urban, and public transportation stations. A focus on priority land use areas allows MS4s to allocate trash control resources to the areas where controls will have the greatest effect.

In some cases, however, non-priority land use areas may generate a substantial amount of trash. Permittees may get approval from the Santa Ana Water Board to substitute one or more of the priority land use areas with an alternate land use area that generates trash at equivalent or greater rates. The Santa Ana Water Board may also determine that a nonpriority land use or location generates a substantial amount of trash. Where this determination is made, the Santa Ana Water Board may require Permittees to adopt Track 1 or Track 2 control measures over these areas. The Order refers to these areas as “designated land use areas.”
Prior to the issuance of the Order, and as contemplated by the Trash Provisions, the Santa Ana Water Board issued Water Code section 13383 Orders to the Permittees on June 2, 2017. The 13383 Orders directed Permittees to select a compliance pathway consistent with either Track 1 or Track 2. All Permittees have replied to the Order, providing notice of which compliance pathway they have elected. Permittees that selected Track 2 submitted an accompanying implementation plan. The Order includes a similar requirement that Permittees elect to follow either Track 1 or Track 2 and provides that the information previously submitted in response to the 13383 Orders may be used in whole or in part to satisfy the requirements of section V of the Order. The Permittee’s selection of either Track 1 or Track 2 and associated submittals must be approved by the Executive Officer. No designated land use areas for trash have been identified as of the issuance of the Order.

The Trash Provisions require that NPDES permits for MS4 contain provisions prohibiting the discharge of trash within ten years of the effective date of the first implementing permit, or no later than fifteen years from the effective date of the Trash Provisions (December 2, 2030).

Consistent with the Trash Provisions, the Order also includes an implementation schedule that requires final compliance with Track 1 or Track 2 to be achieved by December 2, 2030.

Additionally, as an interim milestone, the Permittees must install, operate, and maintain Full Capture Systems (Track 1) or equivalent measures (Track 2) for 50 percent or more of the priority land use areas and equivalent alternate land use areas within 4 years of the effective date of the Order. Permittees may be issued a time schedule order not to exceed 10 years from the determination by the Santa Ana Water Board to designate a land use or location as a designated land use.

VIII. RATIONALE FOR RECEIVING WATER LIMITATIONS
Consistent with State Water Board Orders WQ 99-05 and WQ 2015-0075, section VI of the Order requires compliance with water quality standards in receiving waters. (See State Water Board Order WQ 2015-0075, p. 51.) The receiving water limitations contained in the Order are imposed under CWA section 402(p)(3)(B)(iii), which requires MS4 permits to include “such

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 240 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
other provisions as the Administrator or the State determines appropriate for the control of pollutants.” USEPA interprets this provision to mandate “controls to reduce the discharge of pollutants to the maximum extent practicable, and where necessary water quality-based controls.” (Phase I Stormwater Regulations, Final Rule, 55 Fed. Reg. 47990, 47994 (Nov. 16, 1990) [emphasis added]; see also Building Industry Ass’n of San Diego County v. State Water Resources Control Bd. (2004) 124 Cal.App.4th 866, 882-887).) Water Code section 13377 also requires that NPDES permits include limitations necessary to implement water quality control plans. In Order WQ 2015-0075, the State Water Board reiterated that provisions requiring compliance with receiving water limitations are appropriate for the control of pollutants in MS4 permits and are consistent with the State’s authority under the CWA. (Order WQ 2015-0075, pp. 14, 51.)
The inclusion of receiving water limitations is also consistent with the Ninth Circuit Court of Appeal’s ruling in Defenders of Wildlife v. Browner (191 F.3d 1159, 1166 (1999)). This ruling shows that the permitting authority has discretion regarding the nature and timing of requirements that it includes as MS4 permit conditions to attain water quality standards. The Ninth Circuit Court of Appeals explained that “[w]ater quality standards are used as a supplementary basis for effluent limitations [guidelines] so that numerous dischargers, despite their individual compliance with technology based effluent limitations, can be regulated to prevent water quality from falling below acceptable levels” (NRDC v. County of Los Angeles (2011) 673 F.3d 880, 886). Receiving water limitations are necessary to protect the beneficial uses of the receiving waters and are included in this Order to ensure that individual and collective discharges from the MS4 do not cause or contribute to exceedances of water quality standards.

The receiving water limitations in the Order consist of all applicable numeric or narrative water quality objectives or criteria, or limitations to implement the applicable water quality objectives or criteria, for receiving waters contained in Chapters 3 and 4 of the Basin Plan, or in water quality control plans or policies adopted by the State Water Board, or in federal regulations, including but not limited to 40 CFR section 131.12 and 131.38. The water quality objectives in the Basin Plan and other State Water Board plans and policies have been approved by USEPA. Combined with the designated beneficial uses and the State’s antidegradation policy, the water quality objectives constitute the water quality standards required under federal law.

The receiving water limitations provisions in the Order are largely carried over from the previous permits and are based on precedential State Water Board Orders WQ 98-01, WQ 99-05, and WQ 2015-0075.

Section VI.A of the Order includes a provision that states that Permittees must comply with receiving water limitations “through timely, iterative implementation of control measures/best management practices and other actions to reduce pollutants in discharges according to the conditions and provisions of this Order.” This outlines the “iterative process” whereby certain actions are required when exceedances of receiving water limitations occur and discharges from the MS4 are implicated. However, as the State Water Board noted in Order WQ 2015- 0075, compliance with the “iterative process” is not a “safe harbor” and MS4 discharges that are causing or contributing to an exceedance of water quality standards are in violation of the permit. (Order WQ 2015-0075, p. 12.)
Section IV.E is a new addition to the Order that spells out the pathways for demonstrating compliance with receiving water limitations. One important option is through voluntary implementation of an approved Watershed Management Plan, consistent with the actions and

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 241 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
schedules therein, to address the applicable waterbody-pollutant combination pursuant to section XII of the Order. Additionally, for waterbody-pollutant combination subject to an adopted TMDL, the Permittee may demonstrate compliance with the applicable water qualitybased effluent limitation (WQBEL) for that waterbody-pollutant combination pursuant to section VII of the Order.

IX. RATIONALE FOR EFFLUENT LIMITATIONS AND DISCHARGE

SPECIFICATIONS
Clean Water Act section 402(p)(3)(B)(iii) requires MS4 permits to include “controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants.” The control of pollutants discharged is established through effluent limitations and other requirements in NPDES permits. The Clean Water Act generally requires NPDES permits to include technology-based effluent limitations and any more stringent water qualitybased effluent limitations necessary to meet water quality standards. Both types of limitations are in the Order in section VII and are discussed below.

A. Technology-Based Effluent Limitations (TBELs)
Section 301(b)(1)(A) of the CWA and 40 CFR section 122.44(a) require that NPDES permits include technology-based effluent limitations and standards. A technology-based effluent limitation is based on the capability of a model treatment method to reduce a pollutant to a certain concentration. In 1987, the CWA was amended to require that municipal stormwater discharges “reduce the discharge of pollutants to the maximum extent practicable.” (CWA § 402(p)(3)(B)(iii).) The “maximum extent practicable” (MEP) standard is the applicable federal technology-based standard that MS4 owners and operators must attain to comply, in part, with their NPDES permits.

Federal regulations at 40 CFR section 122.26(d)(2)(iv) further detail the MEP standard, which requires that MS4 owners and operators implement comprehensive pollutant control measures in a stormwater management program including management practices, control techniques and system, design and engineering methods, and such other provisions which are appropriate. Permit requirements to implement the MEP standard are generally referred to, collectively, as pollution controls or best management practices (BMPs).

Examples include street sweeping, requiring erosion controls at construction sites (e.g., straw wattles, silt fences), and catch basin cleanouts. In addition to regulations, USEPA has issued guidance documents that discuss the type of pollution controls and BMPs that should be included in MS4 permits in order to reduce the discharge of pollutants in stormwater to the MEP. (See, e.g., USEPA, MS4 Permit Improvement Guide (2010).) The requirement that MS4 permittees reduce pollutants in stormwater discharges to the MEP remains a cornerstone of the mandate imposed by the federal Clean Water Act and implementing NPDES regulations. Meeting the MEP standard is generally a result of implementing robust pollution prevention and control through various programs and structural measures. These pollution prevention and control methods require Permittees to take actions that will lessen the incidence of pollutants entering the storm drains by regulating the behavior and practices of the Permittees, their residents, and their businesses and controlling the discharge of pollutants through structural measures and treatment methods.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 242 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Neither Congress nor USEPA has specifically defined the term “maximum extent practicable.” Rather, the MEP standard is an ever evolving, flexible and advancing concept, which considers technical and economic feasibility. As knowledge and technology regarding controlling stormwater runoff continue to evolve, so must the actions that are taken to comply with the standard. Congress established this flexible MEP standard so that administrative bodies would have “the tools to meet the fundamental goals of the Clean Water Act in the context of storm water pollution.”37 This standard was designed to allow permit writers flexibility to tailor permits to the site-specific nature of MS4s and to use a combination of pollution controls that may be different in different permits. (In re City of Irving, Texas, Municipal Storm Sewer System (July 16, 2001) 10 E.A.D. 111 (E.P.A.), *6.) The MEP standard is also expected to evolve in light of programmatic improvements, new source control initiatives, and technological advances that serve to improve the overall effectiveness of stormwater management programs in reducing pollutant loading to receiving waters.

USEPA’s clear intent is for stormwater management programs to evolve based on changing conditions from program development and implementation and corresponding improvements in water quality. (See, 55 Fed. Reg. 47990, 48052 [“EPA anticipates that storm water management programs will evolve and mature over time.”]; 64 Fed. Reg. 68722, 68754; Dec. 8, 1999 [“EPA envisions application of the MEP standard as an iterative process.”]; Interim Permitting Approach for Water Quality-Based Effluent Limitations in Stormwater Permits (Sept. 1, 1996) [“The interim permitting approach uses BMPs in first round storm water permits, and expanded or better-tailored BMPs in subsequent permits, where necessary, to provide for the attainment of water quality standards.”]; Revisions to the November 22, 2002 Memorandum “Establishing Total Maximum Daily Load (TMDL) Waste Load Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Las” (Nov. 26, 2014) [“In subsequent stormwater permit terms, if the BMPs used during prior years were shown to be inadequate to meet the requirements of the Clean Water Act (CWA), including attainment of applicable water quality standards, the permit would need to contain more specific conditions or limitations.”].)
To provide clarification to the Regional Water Boards, the State Water Board’s Office of Chief Counsel issued a memorandum dated February 11, 1993 regarding the “Definition of ‘Maximum Extent Practicable’.” In the memorandum, the State Water Board interpreted the MEP standard to entail “a serious attempt to comply,” and that under the MEP standard, “practical solutions may not be lightly rejected.” The memorandum states, “[i]n selecting BMPs which will achieve MEP, it is important to remember that municipalities will be responsible to reduce the discharge of pollutants in storm water to the maximum extent practicable. This means choosing effective BMPs, and rejecting applicable BMPs only where other effective BMPs will serve the same purpose, the BMPs would not be technically feasible, or the cost would be prohibitive.” The memorandum suggests several factors to be considered when choosing BMPs, including effectiveness, regulatory compliance, public acceptance, cost, and technical feasibility. The memorandum further states that, “[a]fter selecting a menu of BMPs, it is of course the responsibility of the discharger to ensure that all BMPs are implemented.”
37 (Building Industry Ass’n of San Diego County v. State Water Resources Control Board (2004) 124 Cal.App.4th 866, 884.)

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 243 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
The Order includes programmatic requirements in six areas pursuant to 40 CFR section 122.26(d)(2)(iv), including numeric design standards for stormwater runoff from new development and significant redevelopment consistent with the federal MEP standard (see State Water Board Order WQ 2000-11, the “LA SUSMP Order”). The Order also includes requirements for a program effectiveness assessment, which includes periodically evaluating and modifying or adding control measures, consistent with the concept that MEP is an evolving and flexible standard.

B. Water Quality-Based Effluent Limitations

1. Basis for Water Quality-Based Effluent Limitations
In addition to requiring that MS4 permits include technology-based requirements consistent with the MEP standard, section 402(p)(3)(B)(iii) of the CWA requires that MS4 permits include “such other provisions as the Administrator or the State determines appropriate for the control of pollutants.” USEPA interprets this provision to mandate “controls to reduce the discharge of pollutants to the maximum extent practicable, and where necessary water quality-based controls.” (55 Fed. Reg. 47990, 47994 (Nov. 16, 1990) [emphasis added].)
USEPA has reiterated that MS4 “permit conditions must provide for attainment of applicable water quality standards (including designated uses), allocations of pollutant loads established by a TMDL, and timing requirements for implementation of a TMDL.” (64 Fed. Reg. 68722, 68737.) USEPA Region IX has also affirmed the Water Boards’ position that MS4 discharges must meet water quality standards in a series of comment letters on MS4 permits issued by various California regional water boards. (See, e.g., letter from Alexis Strauss, Acting Director, Water Division, U.S. EPA Region IX, to Walt Pettit, Executive Director, State Water Board, re: SWRCB/OCC File A-1041 for Orange County, dated January 21, 1998.) Likewise, the State Water Board has affirmed that MS4 permits must include requirements necessary to achieve compliance with the applicable technology-based standard of MEP and to achieve water quality standards. (See, e.g., State Water Board Orders WQ 99-05, WQ 2001- 15, and WQ 2015-0075.) The permitting agency must therefore include provisions in addition to those based on the MEP standard when it finds it is appropriate to do so and to exercise its discretion to determine what permit conditions are necessary to control pollutants in a specific geographic area.

Generally, discharge requirements designed to achieve water quality standards are referred to as water quality-based effluent limitations (WQBELs). A WQBEL is a restriction on the quantity or concentration of a pollutant that may be discharged from a point source into a receiving water that is necessary to achieve an applicable water quality standard in the receiving water. (See 40 CFR § 122.2; NPDES Permit Writer’s Manual, Appendix A.) As discussed more fully below, WQBELs may be expressed narratively or numerically.

Federal NPDES regulations require the permitting agency to include WQBELs for point source discharges that cause, have the reasonable potential to cause, or contribute to an excursion above water quality standards. (40 CFR § 122.44(d)(1)(i), (iii).) As the State Water Board explained in 2001, “Urban runoff is causing and contributing to impacts on receiving waters throughout the state and impairing their beneficial uses....

It is not enough simply to apply the technology-based standards of controlling

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 244 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
discharges of pollutants to the MEP….” (State Water Board Order WQ 2001-15, pp. 7-8.) Nearly two decades later, this is still true.

In the Order, WQBELs are included where the Santa Ana Water Board or USEPA has determined that discharges from the MS4 cause, have the reasonable potential to cause, or contribute to an excursion above water quality standards. (See 40 CFR §§ 122.44(d)(1)(i)-(iii); 122.44(d)(1)(vii)(B).) Reasonable potential can be demonstrated in several ways, one of which is through the TMDL development process. Where a point source is assigned a waste load allocation38 (WLA) in a TMDL, the analysis conducted in the development of the TMDL provides the basis for the Santa Ana Water Board or USEPA’s determination that the discharge has the reasonable potential to cause or contribute to an exceedance of water quality standards in the receiving water.

This approach is affirmed in USEPA’s Permit Writer’s Manual, which states, “[w]here there is a pollutant with a WLA from a TMDL, a permit writer must develop WQBELs.” (NPDES Permit Writers’ Manual, p. 6-30.)
The Santa Ana Water Board and USEPA have each established numerous TMDLs to address water quality impairments in the Santa Ana Region. Through the process of developing these TMDLs and assigning WLAs to MS4 discharges in the Santa Ana Region, the Santa Ana Water Board and USEPA have established that MS4 discharges cause or contribute to exceedances of water quality standards. Given the number of Santa Ana Water Board and USEPA established TMDLs for impaired waters in the Santa Ana Region, there is ample evidence that MS4 discharges are a continuing and significant source of pollutants to the impaired receiving waters notwithstanding implementation of stormwater management programs driven by the MEP standard for the last three decades.

Where a TMDL has been established for a particular waterbody, USEPA’s NPDES regulations further require that, “when developing water quality-based effluent limits…the permitting authority shall ensure that effluent limits … are consistent with the assumptions and requirements of any available wasteload allocation for the discharge…” (40 CFR § 122.44(d)(1)(vii)(B).) In its 2014 memorandum, Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs, USEPA reaffirmed its 2002 interpretation that this regulation requires that “where a State or EPA has established a TMDL, NPDES permits must contain effluent limits and conditions consistent with the assumptions and requirements of the WLAs in the TMDL.” (USEPA Memorandum (Nov. 26, 2014), p. 6 [emphasis added]; see also USEPA Memorandum (Nov. 22, 2002), “Establishing Total Maximum Daily Load Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs”.) This requirement that WQBELs must be consistent with the assumptions and requirements of the WLAs means that the permit must include either an equivalent numeric effluent limit or “a measurable, objective BMP-based limit that is projected to achieve the WLA.” (Ibid.) When a narrative WQBEL in the form of a BMP-based limit is relied upon, “the permit’s administrative record needs to provide adequate demonstration that … the BMPs … will be sufficient to implement applicable WLAs. … Improved knowledge of BMP effectiveness … should be reflected in the demonstration 38 “Wasteload allocation” is defined as “[t]he portion of a receiving water’s loading capacity that is allocated to one if its existing or future point sources of pollution. WLAs constitute a type of water quality-based effluent limitation.” (40 CFR § 130.2(h).)

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 245 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
and supporting rationale that implementation of the BMPs will attain water quality standards and be consistent with WLAs.” (Ibid.)
Further, Water Code section 13377 requires that NPDES permits include effluent limitations necessary to implement water quality control plans, including TMDL requirements that have been incorporated into the water quality control plans.

The Santa Ana Water Board has therefore included WQBELs in the Order for all pollutants for which a TMDL WLA is assigned to the MS4 discharges and the WQBELs are consistent with the assumptions and requirements of available TMDL WLAs applicable to the Permittees.

2. Expression of Water Quality-Based Effluent Limitations While federal law requires the Santa Ana Water Board to include TMDL-based WQBELs in the Order, it does not specify how those WQBELs are to be expressed in MS4 permits. Rather, federal law requires the permitting authority to make that determination as appropriate and necessary for the control of the discharge. In MS4 permits, WQBELs may be expressed either in narrative form (e.g., as requirements to implement specified BMPs) or in numeric form (i.e., as numeric effluent limitations).

Both types of expression of the WQBELs are allowed and neither one is more stringent than the other because an equivalent level of implementation of BMPs or other control measures is necessary to comply in either expression of the WQBELs.

In USEPA’s 2014 Memorandum, Revisions to the November 22, 2002 Memorandum “Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs,” USEPA explained that:

Where the TMDL includes WLAs for stormwater sources that provide numeric pollutant loads, the WLA should, where feasible, be translated into effective, measurable WQBELs that will achieve this objective. This could take the form of a numeric limit, or of a measurable, objective BMP based limit that is projected to achieve the WLA….The permitting authority’s decision as to how to express the WQBEL(s), either as numeric effluent limitations or as BMPs, with clear, specific, and measurable elements, should be based on an analysis of the specific facts and circumstances surrounding the permit, and/or the underlying WLA, including the nature of the stormwater discharge, available data, modeling results, and other relevant information.
(2014 USEPA Memorandum, p. 6.) Where a BMP-based approach to permit limitations is selected, the 2014 USEPA Memorandum notes that the permit’s administrative record needs to provide an adequate demonstration that implementation of the BMPs required in the permit will attain water quality standards and be consistent with the WLAs. (Ibid.)
The Santa Ana Water Board has expressed WQBELs in the Order as numeric effluent limitations as the default standard, but allows Permittees the option to demonstrate compliance narratively. Permittees may comply with the numeric WQBELs either by demonstrating compliance with the numeric WQBELs through monitoring or by

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 246 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
implementing BMPs in approved Watershed Management Plans. Therefore, in essence, the Permit includes both numeric and narrative WQBELs. The Order contains both approaches to protect water quality and provide compliance flexibility for Permittees, while also following USEPA guidance. Compliance with numeric WQBELs through monitoring and analysis of water samples collected from select representative MS4 discharge points is the default compliance standard. Alternatively, Permittees may develop and implement an approved Watershed Management Plan whereby they propose and implement certain approved BMPs that a reasonable assurance analysis (RAA) indicates will meet the applicable numeric WQBELs by specified compliance deadlines.

In determining how to express the WQBELs, the Santa Ana Water Board has analyzed the specific facts and circumstances surrounding the Order and the underlying TMDL WLAs, including the nature of MS4 discharges in the Santa Ana Region, available data, modeling results, and other relevant information. In doing so, the Santa Ana Water Board concludes that WQBELs expressed numerically are appropriate and necessary in the Order to achieve the WLAs after the deadline to comply has passed or where no deadline was established. MS4 discharges constitute a continuing and significant source of pollutants resulting in exceedances of water quality standards in the Santa Ana Region, as evidenced by the number of TMDLs established for impaired waters in the region and identification of MS4 discharges as a source of that impairment. To date, sole reliance on BMP-based requirements has been insufficient to resolve these exceedances. As such, the Santa Ana Water Board finds that WQBELs expressed numerically are necessary to address the historic and persistent exceedances of water quality standards in the Santa Ana Region.

Further, the Santa Ana Water Board concludes that numeric WQBELs are feasible. In the last 20 years, the Santa Ana Water Board and USEPA have established 12 TMDLs for waterbodies in the Santa Ana Region in which WLAs are assigned to Phase I MS4 discharges. A significant part of developing each TMDL entailed analyzing pollutant sources and allocating loads to those sources using empirical relationships, quantitative modeling, and other relevant information. Following the work already conducted to develop the TMDLs, the Santa Ana Water Board concludes that it is feasible to develop numeric WQBELs for MS4 discharges, and that the numeric WQBELs are consistent with the TMDL waste load allocations. There is ample evidence that BMPs and other control measures can be designed proactively (through modeling) to divert, capture, and/or treat MS4 discharges such that it is possible for any such discharges to ultimately meet the numeric WQBELs according to established compliance schedules. Further, given the variability in implementation of stormwater management programs across Permittees, numeric WQBELs create a measurable, objective, and accountable means of controlling MS4 discharges, while providing significant flexibility for Permittees to comply with the numeric WQBELs in any lawful manner, including by working with other Permittees as well as other government agencies and entities to implement cost-effective pollution controls.

While the Santa Ana Water Board finds that inclusion of numeric WQBELs in the Order is appropriate and necessary to achieve compliance with the TMDLs WLAs as required by federal law, at the same time, the Santa Ana Water Board also finds it appropriate to allow permittees to, alternatively and voluntarily, comply with the numeric WQBELs by implementing approved Watershed Management Plans comprised of a suite of BMP-based control measures. Watershed Management Plans must be accompanied

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 247 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
by demonstrations, via the reasonable assurance analysis (RAA), that the BMPs will meet the numeric WQBELs. This alternative, BMP-based compliance option satisfies USEPA’s guidance that MS4 permits include “effective, measurable WQBELs…that is projected to achieve the WLA.” (2014 USEPA Memorandum, p. 6.)

3. Development of Water Quality Based Effluent Limitations for TMDLs As required, WQBELs included in the Order and Appendices 2 through 13 are consistent with the assumptions and requirements of the available WLAs assigned to MS4 discharges in the Santa Ana Region, which have been established in numerous TMDLs. The WQBELs are located in the Appendices for each TMDL.

A TMDL is the sum of the allowable pollutant loads of a single pollutant from all contributing point sources (waste load allocations), non-point sources (load allocations), the contribution from background sources, and a margin of safety. (40 CFR § 130.2(i).) MS4 discharges are considered point source discharges and are assigned waste load allocations (WLAs). A TMDL is a tool for implementing water quality standards and is based on the relationship between pollution sources and receiving water quality. The TMDL establishes the allowable pollutant loads from various sources to a waterbody and thereby provides the basis to establish water quality-based controls or effluent limitations. TMDLs may also include deadlines for attainment of WLAs and specify actions needed as part of an implementation plan.

The WLAs, TMDL targets, and other requirements are established in the Basin Plan as part of a TMDL. The WQBELs in Appendices 2 through 13 are based on the WLAs, deadlines to attain the WLA if specified in the TMDL, and other requirements in the Basin Plan. The targets are not incorporated into the Order as WQBELs. However, attainment of TMDL targets may be used to demonstrate attainment of WLAs. The total combined load allocations and WLAs for other sources in the TMDLs watershed are also not used as WQBELs in the Order. The attainment of the total load allocations for all sources to a receiving waterbody may also be used to demonstrate attainment of the WQBEL. Allowing the Permittees to use targets and total load allocations allows the different dischargers in a watershed to integrate their controls through cooperative efforts. This may occur through pollution offsets, pollution trading, or other means.

Some TMDLs have final compliance deadlines that are expected to fall within the term of the Order. For these, the Appendices allow an alternative, BMP-based approach through an approved Watershed Management Plan (WMP) to comply with the applicable WQBEL up until the final compliance deadline.

TMDLs are subject to changes through amendments to the Basin Plan. If a TMDL is changed, the Order may need to be updated so that the WQBELs implement relevant changes. The WQBELs for each TMDL in the Order are organized into the Appendices to simplify editing of the Order following its initial adoption.

Monitoring to demonstrate attainment of WQBELs is controlled by the requirements of Monitoring and Reporting Program R8-2024-0001. The monitoring, analysis, and reporting must be adequate to reach conclusions about compliance with the WQBELs.

Determinations regarding compliance with WQBELs will be made based on methods that have been approved by the Executive Officer following public notice.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 248 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Table D.10, below, provides the applicable TMDLs’ regulatory approval and compliance dates as well as a summary of each Appendix. Each TMDL implements the applicable WLAs as numeric WQBELS. Where the compliance deadline has not passed or none is specified (for USEPA-adopted TMDLs), the related Appendix allows compliance with a BMP-based WQBEL through implementation of an approved WMP that uses the WLA as a performance metric.

Table D.10: TMDL Approval Dates and Compliance Deadlines TMDL Adoption
Date
State
Approval
Date
OAL
Approval
USEPA
Approval
Compliance
Deadline(s)
Big Bear Lake Watershed
Nutrients (Dry
Hydrologic Condition) 4/21/2006 4/3/2007 8/21/2008 9/25/2007 12/31/2015 Middle Santa Ana Watershed
Bacterial Indicator 8/26/2005 5/15/2006 9/1/2006 5/16/2007 12/31/2015
(dry)
12/31/2025
(wet)
San Jacinto Watershed (Lake Elsinore and Canyon Lake)
Nutrients 12/20/2004 5/19/2005 7/26/2005 9/30/2005 12/31/2020 Newport Bay/San Diego Creek Watershed
Copper 12/2/2022 - - -
USEPA
approval +
12 years
Selenium 8/4/2017 9/20/2018 4/19/2019 6/20/2019 6/20/2049 Toxics (Metals) 6/14/2002
Diazinon &
Chlorpyrifos 4/4/2003 10/15/2003 1/5/2004 2/13/2004
12/1/2007
(Delisted
4/6/2018)
Organochlorine
Compounds
7/15/2011 10/16/2012 7/26/2013 11/12/2013 12/31/2020
Sediment 10/9/1998 11/19/1998 2/2/1999 4/16/1999 4/16/2009 Fecal Coliform 4/9/1999 7/5/1999 12/24/1999 2/28/2000
12/31/2014
(REC1) &
12/31/2030
(SHEL)
Nutrients 10/9/1998 11/19/1998 2/10/1999 4/16/1999 12/31/2012 Coyote Creek (based on San Gabriel River TMDL)

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 249 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Metals 3/26/2007
09/30/2023
(dry)
09/30/2026
(wet)
The following provides a brief summary of the Appendices:
a. Appendix 1 – This Appendix shows the list of Permittees subject to the requirements of the Order.
b. Appendix 2 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Nutrient TMDL for Newport Bay/San Diego Creek Watershed. The Nutrient TMDL was approved by the Santa Ana Water Board, the State Water Board, the Office of Administrative Law (OAL), and the USEPA. The Nutrient TMDL was adopted by the Santa Ana Water Board through Resolution No. 98-9 and amended by Resolution No. 98-100. The WLAs from the Nutrient TMDL are expressed as numeric WQBELs that are effective on the effective date of the Order. The compliance deadline of December 31, 2012 has passed. A BMP-based compliance option through an approved Watershed Management Plan is therefore unavailable to demonstrate compliance with the WQBELs for Nutrients.
c. Appendix 3 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Fecal Coliform TMDLs for Newport Bay. The WQBELs apply to the discharge of indicator bacteria from runoff from MS4s into the Newport Bay affecting both water-contact recreation (REC1) and shellfish harvesting beneficial (SHEL) uses. The Fecal Coliform TMDL was first adopted by the Santa Ana Water Board in Resolution No. 99-10 and later approved by OAL on December 24, 1999 and by USEPA on February 28, 2000. The compliance deadline of December 30, 2014, for the REC1 beneficial use specified in the Basin Plan has passed. However, the compliance deadline of December 31, 2030, for the SHEL beneficial use has not passed. As of the date of issuance of this permit, a Time Schedule Order (R8-2019-0050) has been issued and that provides a time schedule to attain the REC1 WQBELs by December 6, 2024. The WLAs from the Fecal Coliform TMDLs are expressed as numeric WQBELs that are effective on the effective date of the Order. A BMP-based compliance option through the development and implementation of an approved Watershed Management Plan is only available to demonstrate compliance with the WQBEL for SHEL, as the compliance deadline for the REC1 WQBEL has passed.
d. Appendix 4 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Sediment TMDL for the Newport Bay/San Diego Creek Watershed. The Sediment TMDL in the Basin Plan erroneously assigned “load allocations” to the Permittees. They should have been described as “waste load allocations” because MS4 discharges are point sources rather than non-point sources. Point sources are assigned waste load allocations, and non-point sources are assigned load allocations. The Sediment TMDL was first adopted by the Santa Ana Water Board in Resolution No. 98- 101 and subsequently approved by OAL on February 2, 1999, and by USEPA on April 16, 1999. The WLAs from the Nutrient TMDL are expressed as numeric WQBELs that are effective on the effective date of the Order. The compliance deadline of April 17, 2009 (10 years from the date of USEPA’s approval of the sediment TMDL), specified in the Basin Plan, has passed. A BMP-based compliance option through an approved Watershed

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 250 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Management Plan is therefore unavailable to demonstrate compliance with the WQBELs for Nutrients.
e. Appendix 5 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Organochlorine Compounds TMDL for Newport Bay and San Diego Creek. The Organochlorines TMDL was first adopted by the Santa Ana Water Board in Resolution No. R8-2011-0037and subsequently approved by OAL on July 26, 2013, and by USEPA on November 12, 2013. Organochlorine compounds are mainly associated with sediment from historical agricultural lands and former military installations.

Many of these areas are now within the Permittees’ jurisdiction. Organochlorine compounds are carried in the Permittees’ MS4s by fine sediment into receiving waters.

The Permittees report that levels of these compounds have been steadily decreasing in the watershed since the use of organochlorine pesticides has been banned. The Permittees report that dry weather flows discharged from MS4 outfalls contain no detectable levels of organochlorine compounds. The WLAs from Organochlorines TMDL are expressed as numeric WQBELs that are effective on the effective date of the Order.

The compliance deadline for the Organochlorines TMDL of December 31, 2020 has passed. A BMP-based compliance option through an approved Watershed Management Plan is therefore unavailable to demonstrate compliance with the WQBELs for Organochlorine Compounds.
f. Appendix 6 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Diazinon & Chlorpyrifos TMDLs for Upper Newport Bay and San Diego Creek. The Diazinon & Chlorpyrifos TMDLs were first adopted by the Santa Ana Water Board in Resolution No. R8-2003-0039 and subsequently approved by OAL on January 5, 2004, and by USEPA on February 13, 2004. The WLAs from the Diazinon & Chlorpyrifos TMDL are expressed as numeric WQBELs that are effective on the effective date of the Order. The compliance deadline of December 1, 2007 has passed. A BMP-based compliance option through an approved Watershed Management Plan is therefore unavailable to demonstrate compliance with the WQBELs for Diazinon and Chlorpyrifos.
g. Appendix 7 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in TMDLs for Toxic Pollutants (Metals) in San Diego Creek and Newport Bay, promulgated by USEPA on June 17, 2002. These TMDLs were all effective upon promulgation by USEPA. The WLAs are incorporated into the Order as WQBELS that are numeric WQBELs. However, Permittees may alternatively comply with the WQBELs by developing and implementing an approved Watershed Management Plan that employs BMPs that are subject to an iterative improvement process. The WQBELs for copper discharges to Newport Bay will be superseded by the WQBELs in Appendix 10 upon the effective date of the Copper TMDLs for Newport Bay. The WQBELs in Appendix 10 were adopted through Santa Ana Water Board Resolution R8-2022-0012. The WQBELs for all other metals and the WQBEL for copper discharges to San Diego Creek remain effective and unchanged by the adoption of the Copper TMDLs. h. Appendix 8 – This Appendix includes wet weather WQBELs that are consistent with the assumptions and requirements specified in the TMDLs for Metals in Coyote Creek (located within the jurisdiction of the Los Angeles Water Board). This TMDL was promulgated by the USEPA on March 26, 2007. The Los Angeles Water Board adopted an implementation plan for the TMDLs through Resolution R13-004. The implementation plan establishes compliance deadlines of September 30, 2023 for dry weather discharges and September

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 251 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
30, 2026 for wet weather discharges. The WLAs from the Metals TMDLs are expressed as numeric WQBELs that are effective on the effective date of the Order. A BMP-based compliance option through an approved Watershed Management Plan is only available to demonstrate compliance with the WQBELs for wet weather discharges, as the compliance deadline for dry weather discharges has passed.
i. Appendix 9 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Selenium TMDL for Freshwater in Newport Bay Watershed. The Selenium TMDL was first approved by the Santa Ana Water Board on August 4, 2017 in Resolution No. R8-2017-0014 and subsequently approved by OAL on April 19, 2019, and by USEPA on June 20, 2019. The compliance deadline of June 20, 2049 for the WQBELs has not yet passed. The WLAs from the Selenium TMDLs are expressed as numeric WQBELs that are effective on the effective date of the Order.

However, the terms of the TMDL allow for compliance with a BMP Strategic Plan designed to attain the CTR-based water column WQBEL. The WLAs are used in the BMP Strategic Plan as performance metrics to iteratively evaluate and improve the effectiveness of the Permittees’ projects and programs for the attainment of the WQBELs. Unless it is approved as a Watershed Management Plan, the BMP Strategic Plan will not serve as an alternative method of complying with Receiving Water Limitations. j. Appendix 10 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Copper TMDL for Upper and Lower Newport Bay. The Copper TMDL was adopted by the Santa Ana Water Board on December 2, 2022 in Resolution R8-2022-0012 and has been approved by the State Water Board. As of the date of issuance of the Order, the Copper TMDLs have not yet been approved by USEPA and will not become effective unless and until approved by USEPA. The WLAs from the Copper TMDLs are expressed as numeric WQBELs that will be on the effective date upon USEPA approval. The compliance deadline is 12 years after the date of USEPA approval of the Copper TMDL. The Permittees may therefore alternatively comply with the WQBELs by developing and implementing an approved Watershed Management Plan that employs BMPs that are subject to an iterative improvement process. k. Appendix 11 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Bacterial Indicator TMDLs for the Middle Santa Ana Region Watershed (MSAR). The Bacteria TMDLs were adopted by the Santa Ana Water Board on August 26, 2005, and subsequently approved by the State Water Board on May 15, 2006, by OAL on September 1, 2006, and by USEPA on May 16, 2007. The Cities of Claremont and Pomona also discharge to the MSAR, but are covered under separate MS4 Permit No. R8-2013-0043. The WLAs from the Bacteria TMDLs are expressed as numeric WQBELs that will be effective upon the effective date of the Order. The compliance deadline for dry weather conditions specified in the Basin Plan passed on December 31, 2015, while the compliance deadline for wet weather conditions has not passed and is December 31, 2025. The Permittees may therefore alternatively comply with the WQBELs for wet weather conditions only by developing and implementing an approved Watershed Management Plan that employs BMPs that are subject to an iterative improvement process. The Appendix requires that the Comprehensive Bacterial Reduction Plan (CBRP) be revised. The CBRP may function as a WMP if it meets the requirements of section XII and is approved by the Executive Officer as a WQMP. However, the CBRP may not serve as an alternative means of compliance with the WQBEL for dry weather conditions, as that compliance deadline has passed.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 252 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
l. Appendix 12 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Lake Elsinore and Canyon Lake Nutrient TMDLs. The Nutrient TMDLs were first adopted by the Santa Ana Water Board on December 20, 2004, and approved by the State Water Board on May 19, 2005, OAL on July 26, 2005, and the USEPA on September 30, 2005. The compliance deadline of December 31, 2020 has passed. The WLAs from the Nutrients TMDLs are expressed as numeric WQBELs that will be effective upon the effective date of the Order. The Appendix requires that the Comprehensive Nutrient Reduction Plan (CNRP) be updated. Because the compliance deadline for the Nutrient TMDLs specified in the Basin Plan has passed, the CNRP may not serve as an alternative means of compliance with the WQBELs and Receiving Water Limitations.; however, it the CNRP serves as an important roadmap for how the Permittees plan to comply with the WQBELs.
m. Appendix 13 – This Appendix includes WQBELs that are consistent with the assumptions and requirements specified in the Nutrients TMDLs for Dry Hydrological Conditions in Big Bear Lake. The Nutrients TMDLs were adopted by the Santa Ana Water Board in Resolution R8-2006-0023 on April 21, 2006 and subsequently approved by the State Water Board on April 3, 2007, OAL on August 21, 2007, and USEPA on September 25, 2007. The compliance deadline of December 31, 2015 for dry weather conditions has passed. The TMDL currently does not apply to wet weather conditions. The dry weather WLAs are expressed as numeric WQBELs that will be effective upon the effective date of the Order. A BMP-based compliance option through an approved Watershed Management Plan is therefore unavailable to demonstrate compliance with the WQBELs for Nutrients.

X. RATIONALE FOR NEW DEVELOPMENT (INCLUDING SIGNIFICANT

REDEVELOPMENT) PROVISIONS
The requirements of section VIII of the Order are based on 40 CFR section 122.26(d)(2)(iv)(A)(2). The requirements are designed to reduce the discharge of pollutants from areas of new development and significant redevelopment. 40 CFR section 122.26(d)(2)(iv)(A) requires, in part, that applicants for MS4 permits provide both “structural and source control measures to reduce pollutants from runoff from commercial and residential areas”.

Section VIII. of the Order also includes a requirement whose purpose is to advance work to retrofit existing flood control facilities to remove pollutants as required by 40 CFR section 122.26(d)(2)(iv)(A)(4). Section VIII includes requirements regarding the sizing of treatment control measures, a selection process that prioritizes LID treatment control measures, and controls for Hydrologic Conditions of Concern. Section VIII also classifies “priority projects”, which require project Water Quality Management Plans (WQMPs) and subsequently, source controls and treatment controls, if they are subject to discretionary action by the Permittee. A priority project that is subject to ministerial action by the Permittee does not need a WQMP if the project meets requirements for source control measures through standardized requirements or other methods.

The Permittees have broad authority to regulate activities within their communities. The Permittees’ authority may not apply to all projects that occur within the physical boundaries of each municipality. For example, Permittees may lack the jurisdiction to require WQMPs for projects carried out by federal agencies, special districts, or other entities. It is not practical to fully describe the limits of the Permittees’ jurisdiction in this Order. The Permittees are

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 253 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
expected to fully exercise their authority to reduce the discharge of pollutants from new development and significant redevelopment according to 40 CFR section 122.26(d)(2)(iv)(A)(2) and the MEP standard.

Projects are generally approved by Permittees as either “discretionary” or “ministerial” projects. A “ministerial” project involves a decision applying “only the use of fixed standards or objective measurements” that the permitting authority previously adopted, with little or no “subjective judgement in deciding whether or how the project should be carried out” (Cal.

Code Regs., tit. 14, § 15369). A “discretionary” project requires the exercise of judgement or deliberation when a project decision is made (Cal. Code Regs., tit. 14, § 15357). Whether a project is discretionary or ministerial depends on the specific ordinances that authorize the decision. This can vary from Permittee to Permittee. The requirements in section VIII.B provide for the even application of pollution controls for priority projects regardless of whether the project is subject to discretionary or ministerial action. Nevertheless, in recognition of the need for more streamlined permitting of projects that don't otherwise need project-level CEQA review, only discretionary projects are subject to section VIII.C.

The Order establishes that “priority projects” are defined by the categories in section VIII.B.5.

Priority projects that are subject to the Permittee’s discretionary approval must have a combination of source control and treatment control measures. These controls must be documented in a project-specific Water Quality Management Plan.

If it is approved through a ministerial action, a priority project is required to have source control measures, such as permeable pavements or enclosures or diversions that prevent pollutants from being mobilized in stormwater. These controls must be enforced either through ordinances, building standards, or similar standardized requirements or a project Water Quality Management Plan.

The previous permits required that Permittees develop project WQMPs based on processes described in model WQMPs. The previous permits required that the design of the project’s pollution controls conform to technical criteria in a Technical Guidance Document. The Permittees in each county developed their own set of documents. Both the model WQMPs and Technical Guidance Documents were incorporated by reference and enforceable under the previous permits.

In this Order, the requirements pertaining to project WQMPs are based on the model WQMPs and Technical Guidance Documents for each county. The processes and requirements of the documents are expressed as requirements directly in the Order. There are usually differences in the language of the documents for each county for the same processes. To reconcile the differences in the counties’ documents, this Order focuses on the underlying common purposes and makes those the requirements of the Order. This approach generally allows the Permittees to continue to use their processes provided they serve the purposes indicated in the Order. The Order does require the Permittees to update their documents and submit them for approval, so they integrate the changes discussed below.

In other cases, during program audits, Santa Ana Water Board staff found project WQMPs that resulted in problematic outcomes related to the quality, serviceability, and safety of treatment control measures. These outcomes did not necessarily affect the treatment performance of the treatment control measures in the short term, but they have the potential to negatively affect the ability of the operator to service the facility and the safety of the surrounding community. Santa Ana Water Board staff found that some Permittees lacked a

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 254 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
comprehensive set of standards to apply during the development of WQMPs that would prevent these problems. The Order adds new requirements for Permittees to have standards and guidelines for these purposes.

Section VIII also includes the following new features and changes over previous permits:

1. Section VIII.B makes clear that Permittees must consider the whole of the project in classifying a project as a priority or non-priority project. This is not intended to cause the Permittees to require WQMPs for projects for which there is insufficient detail to meaningfully develop those plans (e.g., simple lot line adjustments without further development details). The intent is to cause as early consideration of pollution controls as practicable and to prevent projects from being parsed out to avoid preparing a WQMP or source controls and treatment controls.

2. Projects consisting solely of the replacement, upgrade, or installation of dry utilities, sanitary sewer, petroleum pipelines, or water supply distribution lines in existing rights of way have been excluded from “redevelopment projects” that are priority projects.

Redevelopment projects do not include public drainage improvement projects that do not involve new sources of pollution. The reason for this exclusion is because the scope of such projects is too narrow to afford opportunities to include treatment control measures.

Additionally, the post-construction water quality impacts may not be related to the work completed underground. This exclusion does not apply to other related improvements that may be a source of urban pollution, but which would not be a priority project in themselves.

3. The language of section VIII.B allows a Permittee to authorize the continued use of treatment control measures that were installed earlier as part of a previously approved WQMP. This allowance does not apply if the old WQMP was not properly approved or implemented, regardless of whether any enforcement action was taken by the Water Board.

4. Section VIII places new restriction on the use of USEPA guidance, “Managing Wet Weather with Green Infrastructure: Green Streets”. The guidance contains few enforceable standards for selecting structural treatment controls for priority projects that involved improvements to existing transportation rights of way. Transportation rights of way can make up 10% to 25% of an urban area and are a source of pollutants from tire and break wear, aerial deposition of combustion by-products, automotive fluid, littering, collision debris, and landscape maintenance39,40,41. The level of effort for analyzing the feasibility of structural treatment controls, or their use at all, was largely left to each Permittee’s discretion. Audits and inspections by Santa Ana Water Board staff have shown that some Permittees used that discretion to exclude structural treatment controls 39 Sources vary depending on if measurements include sidewalks and greenspace. Statistica, 2023 Urban area allocated to streets in selected cities 2019 | Statista, accessed October 20, 2023. 40 Nixon, H. and Saphores, JD, 2007. Impacts of motor vehicle operation on water quality in the US – Cleanup costs and policies. Transportation Research Part D: Transport and Environment, vol. 12, issue 8, December 2007.
41 UNHabitat, 2013. Streets as public spaces and drivers of urban prosperity, United Nations Human Settlements Programme, Nairobi, Kenya, 2013.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 255 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
with no meaningful analysis in conflict with their obligation to reduce the discharge of pollutants to the maximum extent practicable.

This Order requires expansion of the Permittees’ existing electronic databases for tracking sites affected by an approved WQMP in section VIII.C.11. Treatment control measures that were installed prior to the previous term MS4 Permits were not required to be tracked in an electronic database. However, treatment controls measures were being installed under the MS4 permits adopted almost two decades ago. The performance of these older facilities is also of interest to the stormwater program and may provide practical insights to the Permittees and the Santa Ana Water Board. Consequently, section VIII.C.11 requires that these older facilities be tracked as they are discovered through the Permittees’ inspection programs or with other opportunities.

The project WQMP is intended to accomplish several purposes. First, the project WQMP documents the rationale behind the selection of treatment control measures. Second, the WQMP functions as an enforcement mechanism to provide for the proper construction, operation, and maintenance of treatment control measures for both the project proponent and their successors and assigns over the life of the project. Last, for some larger projects, the project WQMP can serve as a planning document for the design, construction, and funding of regional and sub-regional treatment control measures. As such, it is important that subsequent WQMPs and non-priority project plans be consistent with the larger project WQMP. It is also important that project WQMPs be protected against loss or damage in a manner that is commensurate with the expected duration of the project as required by section VIII.C.25. The loss of project WQMPs and the presence of internal inconsistencies risks undermining the Permittees’ authority to enforce implementation of those plans.

This Order requires the Permittees to establish a program for the improvement of project WQMPs. The Permittees must have written technical guidance for the preparation of project WQMPs. The Model WQMPs and their accompanying Technical Guidance Documents are generally expected to serve this purpose. These documents may require some modifications to comply with the Order, subject to approval by the Executive Officer. Resulting project WQMP process improvements may be made with input from stakeholders. However, the changes must not conflict with the requirements of the Order and are subject to approval.

A. Hierarchy for Treatment Control Measures
This Order maintains the hierarchy for the selection of treatment control measures for priority projects that was prescribed in the previous permits with some modifications. USEPA has urged the Santa Ana Water Board to allow certain project proponents to offset untreated design capture volumes by retrofitting off-site in existing developments. This option appears in the hierarchy so that a project cannot be eligible for a waiver until the offset option and all other options are determined to be infeasible.

To communicate the hierarchy clearly, the Order establishes terminology for categories and subcategories of treatment control measures. This terminology is defined in the Glossary of the Order and is explained below.

In summary, the hierarchy places greatest preference on retention LID best management practices, second preference is for bio-treatment control measures, and third preference for non-LID treatment control measures. A fourth preference has been added for off-site retrofits of existing development to accommodate USEPA’s request.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 256 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Retention LID treatment control measures and bio-treatment control measures are subcategories of LID treatment control measures. LID treatment control measures also include certain source control measures that attempt to mimic the site’s predevelopment hydrology by using techniques that retain runoff close to its source. Although this Order does not require that LID treatment control measures be located on site, LID source control measures should be on site consistent with LID principles.

The effectiveness of LID treatment control measures has been demonstrated in various studies. Dr. Richard Horner demonstrated that LID control measures achieved significant reductions in pollutant loading and runoff volume and enhanced recharge rates compared to developments with no BMPs and those with basic treatment control measures (Horner, 2006)42
. Consequently, the Order emphasizes the use of LID treatment control measures.

Retention LID treatment control measures generally employ infiltration or some other loss of the design capture volume and as such, are generally a more reliable way of preventing the discharge of pollutants in stormwater. Consequently, retention LID treatment control measures are given the greatest degree of preference in the hierarchy.

Retention LID treatment control measures are a subcategory of LID treatment control measures where the design capture volume is either infiltrated into the ground; used for irrigation, process water, or other purposes; or is subject to evaporation or evapotranspiration.

Permittees are responsible for demonstrating in the project WQMP that retention LID treatment control measures, located either on or off-site, are given priority consideration according to the Order’s requirements, before considering any of the subsequent categories of treatment control measures in the hierarchy.

The second category of treatment control measures that must be considered are biotreatment control measures. As indicated by the name, biotreatment control measures are a subcategory of LID treatment control measures that principally remove pollutants through a combination of infiltration, evapotranspiration, biological uptake or transformations, or degradation. While a significant portion of the design capture volume is typically infiltrated or subject to evapotranspiration, this is incidental, and no portion of the design capture volume must be treated in either manner. After passing through a biotreatment control measure and partly evaporated and infiltrated, the remaining portion of the design capture volume is typically discharged from the site. Where retention LID control measures are infeasible, biotreatment control measures must be used where feasible.

The last category of treatment control measures in this Order’s hierarchy are non-LID treatment control measures. Treatment control measures principally use filter media such as perlite, zeolite, sand, or some proprietary or non-proprietary media to physically remove pollutants in stormwater. The media may develop microbial communities in biofilms that coat portions of the media. Biofilms can incidentally assist in removing pollutants through biological uptake and transformation. Biofilms may adversely affect the hydraulic performance of the facility and produce potential pollutants in the effluent.

The Order does not require that a single treatment control measure be used to treat the design capture volume for a drainage area on a priority project site. A series of treatment control measures may be used if necessary. The selection and sizing of controls must follow the Order’s hierarchy. For example, if a retention LID measure cannot treat the entire design 42 Horner, Richard R. Investigation of the Feasibility and Benefits of Low-Impact Site Design Practices (LID) for San Diego, University of Washington, 2006.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 257 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
capture volume, the remaining portion may be treated in a biotreatment control measure. If it is infeasible for both the retention LID and biotreatment control measure to treat the entire design capture volume, then a non-LID treatment control measure may be employed to treat the remaining portion. Under extremely limited circumstances should a site treat the design capture volume or any portion thereof using a non-LID control measure without having demonstrated in the WQMP that the volume could not have been treated using a BMP higher up on the hierarchy.

Section VIII.H of the Order establishes a specific protocol for selecting non-LID treatment control measures. This protocol largely carries over from previous permits. It requires that the Permittees categorize non-LID control measures by type and then assign a performance rating of “high”, “medium”, and “low” to each category relevant to a variety of expected pollutants. As the result of Santa Ana Water Board staff observations during audits of miscategorizations, the Order requires that BMP categories include only those controls that employ the same principal of operation, use similar treatment mechanisms, and which can reasonably be expected to exhibit generally similar performance in the removal of pollutants.

The rating must be based on the best available, objective evidence. The evidence must include field performance test data that is specific to the BMP and that has been collected according to published and recognized protocols.

The non-LID BMP selection protocol also requires that project types be related to various pollutants which can be reasonably expected to be found in runoff from those project types.

Permittees must select non-LID control measures that provide either a “medium” or “high” level of treatment for those projects. Numeric performance thresholds must be used to distinguish the levels of treatment. The performance ratings for non-LID control measures must be reviewed biennially so that they are supported by the best available information.

Like other infrastructure, treatment control measures may pose environmental hazards such as flooding, providing habitat for disease vectors, creating nuisances such as odors or midges, adversely affecting groundwater or soil remediation efforts, or presenting physical hazards to people, nearby structures, or traffic. The Order establishes an obligation on the Permittees to mitigate these potential environmental hazards.

The Order also requires that treatment control measures substantially conform to published and generally accepted engineering design criteria or have had their expected performance substantiated in field tests using published and recognized protocols. These requirements are related to hazard mitigation because, in many cases, engineering design criteria have been established to address potential environmental hazards.

Permittees may use protocols established by authoritative third parties, such as the Washington State Department of Ecology’s Technology Assessment Protocol – Ecology (TAPE) and the New Jersey Comprehensive Assessment Tool (NJCAT) to establish the expected performance of controls. Similarly, Permittees may use published and generally accepted engineering design criteria established by third parties. Minor deviations from published design criteria are generally acceptable and may be done to accommodate LID treatment control measures at a project site. However, major deviations are not acceptable.

B. Integration of Project WQMPs into the Development Application Process The Order establishes a procedure for the integration of project WQMPs into the development application process. This procedure is based on the Model WQMPs developed by the

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 258 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Permittees according to earlier permits. The procedure furthers efforts to “develop, implement, and enforce controls to reduce the discharge of pollutants from [MS4s] which receive discharges from areas of new development and significant redevelopment” down to the project-level according to 40 CFR section 122.26(d)(2)(iv)(A)(2).

The Order requires that project WQMPs be developed in two phases. In the first phase, a preliminary project WQMP must be prepared prior to a project’s development application being regarded as complete. The preliminary project WQMP must be approved before the project is approved by the Permittees’ decision-making body.

The purpose of preparing a preliminary project WQMP prior to the development application being complete is to promote consideration of treatment control measures as early in the development approval process as possible. Treatment control measures often compete for space with other structural elements of a project such as building footprints, utilities, and landscaping. As such, they should be given equal consideration so that they can be integrated into a site in the most economical manner possible. The preliminary project WQMP should be sufficiently detailed to demonstrate that adequate consideration has been given to the sizing, location, type of treatment control measures, and the related BMP hierarchy, such that those measures can be reasonably expected to be constructible, serviceable, and operate as intended.

Once the development application is complete, a project is typically approved after environmental review occurs under CEQA. It is important that treatment control measures be described in the circulated CEQA document. This circulation helps to educate the public on how the Permittee addresses the potential water quality impacts of the project and how the potential environmental hazards of treatment control measures are addressed. For this purpose, the Permittees are encouraged to also describe their related inspection and enforcement programs. Where applicable, the circulated document is a useful compliance monitoring tool for the Santa Ana Water Board and other interested agencies such as the California Coastal Commission and the Department of Fish and Wildlife.

The second phase of WQMP development begins after project approval. During this phase, additional project details are developed, including details on source-control, site-design, treatment control measures, and hydromodification.

Hydromodification is generally defined as changes in channel form associated with alterations in flow and sediment due to past or proposed future land use alterations. The State Water Board’s Construction General Permit, Order No. 2009-0009-DWQ as amended by Order Nos. 2010-0014-DWQ and 2012-0006-DWQ, defines hydromodification as the alteration of the hydrologic characteristics of coastal and non-coastal waters, which in turn could cause degradation of water resources. Hydromodification can cause excessive erosion and/or sedimentation rates, resulting in excessive turbidity, channel aggradation, and/or degradation.

Hydromodification activities change a waterbody's physical, biological, or chemical structure as well as its natural function. These changes can cause problems such as changes in flow, increased sedimentation, higher water temperature, lower dissolved oxygen, degradation of aquatic habitat structure, loss of fish and other aquatic populations, and decreased water quality. In addition, runoff reaches the stream channel much more efficiently, so that the peak discharge rates for floods are higher for an equivalent rainfall than they were prior to development.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 259 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Correcting the root causes of hydromodification is most effective if based on an integrated watershed-scale. Most jurisdictions in California are now required to address the effects of hydromodification through either a municipal stormwater permit or the statewide Construction General Permit. The Order provides the Permittees with opportunities to address the impacts of hydromodification through watershed management.

Because multiple departments can be working on developing separate aspects of a project, there is potential for inconsistencies to develop between different project plans and the preliminary project WQMP. This has the potential to affect BMP selection, the likelihood that a treatment control measure will be built, or the likelihood that it will function as intended. At the end of the second phase, a final project WQMP is approved, and the project is approved to initiate construction.

C. Non-Priority Projects
Previous permits required source controls for non-priority projects regardless of the risk of stormwater pollution. Due to the broad range of projects subject to the Permittees’ approval, this inclusive approach encompassed projects that would occur entirely indoors or whose scope was too narrow to offer opportunities to incorporate the required control measure in a practicable way. As part of the preparation of the Model WQMPs and Technical Guidance Documents, the Permittees narrowed down the scope of non-priority projects requiring a plan by re-defining a non-priority project. Santa Ana Water Board staff did not object to this narrowing because they recognized that the term "non-priority" project was exceptionally inclusive.

The Order discontinues efforts to apply source control measures for non-priority projects. The effort was overly inclusive and Santa Ana Water Board staff found no indication that it was effective.

D. Treatment Control Measures Related to New Development and Significant Redevelopment Versus Other Treatment Control Measures
The requirements for treatment control measures apply only to those control measures constructed as part of priority projects. Priority projects generally involve changes to the environment that create opportunities to install reliable, quality treatment control measures as part of new development and significant redevelopment with relatively few constraints.

There may be other opportunities to install treatment control measures as standalone projects (i.e., not as part of a priority project). These may include in-stream projects that improve the physical or biological integrity of waters or increase the natural pollutant attenuation function of water. They may also include retrofitting an MS4 facility, such as a flood control basin or channel, to promote infiltration, filtration, or other mechanisms to remove pollutants. These projects are more likely to face constraints that conflict with published design standards. They are also likely to treat runoff from existing development that may be causing or contributing to existing exceedances of water quality objectives. To promote their construction, the Santa Ana Water Board does not require that these BMPs meet the same standards as those for treatment control measures built for new development and significant redevelopment.

The requirements of the Order are designed to remove unnecessary constraints on the use of regional and subregional treatment control measures. Due to their larger tributary areas, regional and subregional treatment control measures may contain developed and

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 260 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
undeveloped areas. Proponents of new development and significant redevelopment projects may be funding partners for regional and subregional treatment control measures.

Various funding mechanisms may be used to facilitate these partnerships. The term “credit,” as used in the Order is intended to be interpreted broadly to refer to various funding mechanisms to build and operate regional and subregional treatment control measures.

The Order is not intended to put unnecessary constraints on funding mechanisms. But it is intended to enforce appropriate quality standards for BMPs constructed to serve new development and significant redevelopment. This is accomplished by limiting credits allowed for new development and significant redevelopment to treatment volumes or flows that can meet the Order’s treatment requirements.

The Santa Ana Water Board recognizes that in some cases, MS4 facilities are used to convey runoff to sub-regional or regional treatment control measures or may incorporate regional BMPs directly. The Santa Ana Water Board recognizes this as an appropriate strategy to remove pollutants from discharges in runoff from existing and new development, provided waters of the U.S. are not used to convey pollutants that have not been reduced to the MEP.

E. Regional and Subregional Treatment Control Measures
The provisions of the Order take a neutral position with respect to the use of on-site or off-site treatment control measures. An off-site facility generally will serve more than one project or property owner and will generally be a regional or sub-regional facility. Instead, preference is given in the Order to LID treatment control measures, with less regard to their location. This represents a significant shift from prior permits, which required a demonstration that on-site treatment facilities were infeasible before allowing the use of an off-site facility.

This shift regarding the location of treatment control measures considers the benefits of centralizing these BMPs. In comparison with de-centralized treatment control measures, centralized facilities consolidate the responsibility for their operation and maintenance into a single entity, such as a property owner’s or homeowner’s association, a community facilities district, or public agency. This allows for the facility to be professionally managed and maintained, which may allow the facility to perform more reliably with less risk of premature failure. Centralized facilities also consolidate the costs of construction, operation, and maintenance and may result in efficiency of scale. Centralized facilities are more likely to collect runoff from roadways and other public rights of way whose runoff might be treated using less effective BMPs. Centralized facilities may also be on a scale that they provide other community benefits, such as open space.

In sum, the Order changes the requirements for new development so that there is no preference to the use of treatment control measures either on or off-site. The Order makes it easier for a project proponent to use an off-site treatment control measures where they are available. This is accomplished principally by not requiring that on-site treatment control measures be demonstrated to be infeasible before allowing the use of an off-site facility.

F. Alternatives and In Lieu Programs
Previous permits allowed the Permittees to organize runoff funds to pay for urban water quality improvement projects within the same watershed. These would be funded by contributions from developers who were granted waivers. No MS4 runoff fund was ever reported to be

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 261 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
established for “urban water quality improvement projects” and no waivers are known to have been issued during the previous permits’ terms. If a waiver was issued under the previous permits, Permittees were not required to develop funds and collect monies. Because obtaining a waiver poses little relative cost versus a contribution to a fund, it is not surprising that the Permittees chose not to impose the financial burden of a runoff fund on the development community. Nonetheless, at the urging of USEPA, the Order continues to allow the Permittees to exact funds from projects which are granted waivers.

The previous permits also allowed the Permittees to establish a water quality credit system for alternatives to infiltration, harvesting and reuse, evapotranspiration, and other LID treatment control measures and hydromodification requirements. However, the projects listed as eligible for credits are generally regarded as low-impact development, such as transitoriented development, urban in-fill projects, and high-density developments over 7 dwelling units per acre. This suggests that the purpose of the credit system was to encourage these types of development.

To be effective, the discounts on the design capture volume would have to influence a project proponent to change a non-LID project to a LID project or to essentially propose a project that otherwise would not have been proposed in the face of constraining factors. To do so, the savings realized from the discount on the design capture volume would have to exceed the costs of overcoming any of the factors that limit LID. In some cases, this may be costly, involve changing zoning; overcoming local opposition to certain forms of development; mitigating infrastructure impacts such as traffic, sewer, and water; or providing funding for more police and fire services.

The Permittees have not reported, and Santa Ana Water Board staff is unaware of any evidence that those discounts have been effective at motivating the Permittees or the development community to alter development patterns or to produce more LID projects than would have been produced without the discounts. Because of this, the discounts have been an unnecessary compromise on the protection of water quality. Therefore, the Order no longer allows the Permittees to provide discounts on the design capture volume. The Order does not require the Permittees to take back any discounts granted before the effective date of the Order.

G. Credit Trading
The Order authorizes the Permittees to establish a water quality credit system but in a different form than previous permits. The Order essentially allows an entity to construct a LID treatment control measure that treats runoff from a drainage area that does not necessarily include the area of a project. The entity or project proponent is then allowed to trade the treatment capacity with projects in the same drainage area of the same receiving waters (waters of the U.S.) subject to certain conditions. The “excess” capacity is the design capture volume or flow that the facility treats minus the volume or flow generated by a related project, if any. This excess capacity is a “credit” that serves as a unit of trade between projects. This marketbased feature of the permit is designed to encourage early investments in LID BMP infrastructure for large or multi-property property owners. The Order does not regulate the manner of the transaction between projects, but the treatment control measure employed to produce the credit must be a LID BMP.

Permittees are allowed to trade credits between projects, but the projects must discharge to the same nearest receiving waterbody. This is a limitation on the size of the trading market.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 262 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Because credit trading is tied closely to redevelopment investment, and redevelopment does not tend to be evenly distributed, there is a risk that credit trading at larger scales would concentrate the benefits and risks across different communities. This could result in pollution hotspots that disproportionately affect disadvantaged communities. The limitation that the discharge be to the same nearest receiving waterbody is also necessary at this time because permitting a larger trading market would require a more complex system of accounting and controls coordinated across multiple Permittees. Few Permittees may be prepared to effectively manage credit trading at a larger scale.

XI. RATIONALE FOR ILLICIT DISCHARGE DETECTION AND ELIMINATION

PROGRAM
Section IX of the Order includes requirements intended to cause the Permittees to effectively prohibit illicit discharges and illicit connections and to detect and remove improper disposal to MS4s in accordance with 40 CFR section 122.26(d)(2)(iv)(B). Discharges that are authorized under an NPDES permit or are otherwise authorized or conditionally exempt under section IV.A are not considered illicit discharges.

In its 1990 rulemaking, USEPA explained that the illicit discharge detection and elimination (IDDE) program requirement was intended to begin to implement the CWA’s provision requiring permits to “effectively prohibit non-stormwater discharges.” (55 Fed. Reg. 47990, 47995.) Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B) require that the stormwater management program shall be based on “a description of a program, including a schedule, to detect and remove (or require the discharger to the municipal storm sewer to obtain a separate NPDES permit for) illicit discharges and improper disposal into the storm sewer.” The proposed management program shall include “[a] description of a program, including inspections, to implement and enforce an ordinance, orders or similar means to prevent illicit discharges to the municipal storm sewer system,” per subsection (1) of the above federal regulation.

Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(1) through (7) provide the IDDE program requirements including a “description of a program, including inspections, to implement and enforce an ordinance, orders or similar means to prevent illicit discharges to the municipal separate storm sewer system,” field screening, investigation procedures, spill prevention, public reporting, educational activities, and a description of controls to limit infiltration of seepage from municipal sanitary sewers.

Section IX of the Order describes requirements for programs to address illegal discharges, illicit connections, and illegal dumping. The programs must include procedures for investigating the source of illicit connections and illegal discharges. The Permittee must continue to implement their IDDE program, maintain it in written form, and update it, as necessary. The requirements in the IDDE program are retained from previous permits for Santa Ana Region and have been reworded for improved clarity.

The Order adds a timeline of three business days to initiate source investigations of illicit connections and illegal discharges. USEPA encourages permit writers to include clear, specific, measurable requirements in permits, as is evident through the Phase II remand rule and guidance documents. (See USEPA. 2016. National Pollutant Discharge Elimination System [NPDES] Municipal Separate Storm Sewer System General Permit Remand Rule, 81 Federal Register, p 89326; USEPA. 2010. MS4 Permit Improvement Guide. April 2010. p.5.)

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 263 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
This Order also clarifies that Sanitary Sewer Overflows (SSOs) are a sub-class of illicit discharges consistent with 40 CFR section 122.26(d)(2)(iv)(B)(4) and (7). Federal regulations at 40 CFR section 122.26(d)(2)(vi)(B)(7) require that the IDDE program include “[a] description of controls to limit infiltration of seepage from municipal sanitary sewers to municipal separate storm sewer systems where necessary.” Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(4) also require a “description of procedures to prevent, contain, and respond to spills that may discharge into the municipal separate storm sewer.” Except for general requirements for IDDE, this Order does not create new SSO requirements for Permittees already subject to Order No. 2022-0103-DWQ. This Order includes requirements that provide an incentive for Permittees to cooperate in efforts to eliminate SSOs. SSOs are prohibited by Order No. 2022-0103-DWQ (Provision C.1.) and are a form of illicit discharge which the Permittees must effectively prohibit. This Order does not require that Permittees, who do not operate wastewater collection systems, take on any responsibilities of system operators. The exact nature of the cooperative relationship between wastewater collection system operators and non-operator Permittees is left to the Permittees’ discretion but it must be consistent with a genuine effort to effectively prohibit SSOs.

Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(5) require the Permittees to develop a description of a program “to promote, publicize, and facilitate public reporting of the presence of illicit discharges or water quality impacts associated with discharges from municipal separate storm sewer.” The Permittees need to promote the program to help in the identification and termination of illicit discharges. The Order establishes requirements for the Permittees, individually or as a group, for public reporting of illicit discharges. Permittees must provide the public with at least one way of reporting illicit discharges, spills, and observed water quality impacts associated with the MS4.

Permittees must track all suspected sources of non-stormwater discharges, including sources suspected of being sanitary sewage. Tracking requirements have been added to the Order.

Documenting and tracking of illicit discharges will help to ensure that all illicit discharges are investigated and addressed, and water quality is protected. This is consistent with USEPA’s MS4 Permit Improvement Guide, which provides an example requirement to “track all investigations to document at a minimum the date(s) the illicit discharge was observed; the results of the investigation; any follow-up of the investigation; and the date the investigation was closed.” (USEPA. 2010. MS4 Permit Improvement Guide. April 2010. p. 33.) Other USEPA-issued permits, such as for the Boise Area (NPDES permit IDS-027561), include similar approaches to IDDE, which require Permittees to maintain a record documenting all complaints or reports of illicit discharges and responses taken by Permittees.

XII. RATIONALE FOR PUBLIC EDUCATION AND OUTREACH PROVISIONS Section X of the Order requires that the Permittees implement an effective public education program. The requirements of section X are based on 40 CFR section 122.26(d)(2)(iv)(A)(6), (B)(6), and (D)(4). The public education program, as currently implemented under prior permits, has been a core element of the Permittees’ stormwater program for over a decade.

Federal regulations at 40 CFR section 122.26(d)(2)(iv) require as part of a stormwater management program “a comprehensive planning process which involves public participation and where necessary intergovernmental coordination, to reduce the discharge of pollutants to the maximum extent practicable using management practices, control techniques and system, design and engineering methods, and such other provisions which are appropriate.”

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 264 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Federal regulations at 40 CFR section 122.26(d)(2)(iv)(A)(6) provide that the proposed management program include “[a] description of a program to reduce to the maximum extent practicable, pollutants in discharges from MS4s associated with the application of pesticides, herbicides, and fertilizer which will include, as appropriate, controls such as educational activities, permits, certifications, and other measures for commercial applicators and distributors, and controls for application in public right-of-way’s and at municipal facilities.” Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(6) provide that the proposed management program includes “[a] description of education activities, public information activities, and other appropriate activities to facilitate the proper management and disposal of used oil and toxic materials.”
Federal regulations at 40 CFR section 122.42(c) require the owner or operator of an MS4 to submit an annual report that includes in part “(1) The status of implementing the components of the storm water management program that are established as permit conditions; (2) Proposed changes to the storm water management programs that are established as permit condition. Such proposed changes shall be consistent with §122.26(d)(2)(iii) of this part…” and “(6) A summary describing the number and nature of enforcement actions, inspections, and public education programs; …
The purpose of section X of the Order is to raise the public’s awareness of pollution in runoff from MS4s and to cause the public to take action to reduce that pollution. The changes to the requirements in this Order have been largely influenced by USEPA’s document, Getting in Step: A Guide for Conducting Watershed Outreach Campaigns. Changes were also made to generally support the effective execution of public education campaigns.

The Order now requires that the Permittees initiate public education campaigns that address a minimum of three high priority pollution goals during the term of the permit. The Order does not dictate when a campaign must end. A campaign may carry over into another permit term.

Other than initiating campaigns on three goals, the Order does not specify any specific milestones or other performance metrics for those campaigns. Instead, the Permittees must identify goals and performance metrics and evaluate the program’s effectiveness and pursue continual improvement according to the requirements of the Order.

The Permittees have the discretion to select the pollution goals and objectives of the public education campaign. The Permittees’ rationale for their selection must consider water quality data, public surveys, specific local conditions, social science research, and other objective information. The Permittees must permit public input on the overall campaigns, including the goals and performance metrics.

Permittees who elect to develop and implement a WMP shall identify how public education and outreach will be implemented to address the high priority pollution issues. The Permittees have the flexibility to optimize water quality improvements by shifting resources and taking different approaches to achieving desired outcomes.

XIII. RATIONALE FOR TRAINING PROGRAMS
Section XI of the Order continues the requirements of the previous permits with some modifications. The requirements of section XI are based in part on 40 CFR section 122.26(d)(2)(iv) which requires, in part, that applicants for MS4 permits describe staff available

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 265 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
to implement their stormwater program and on certain required training and education programs in 40 CFR section 122.26(d)(2)(iv)(A)(6), (B)(6), and (D)(4).

For Permittees to be effective in implementing the stormwater programs, staff need to be aware of their employer’s obligation to reduce the discharge of pollutants and their duties to help fulfill that obligation. These requirements are in accordance with CWA section 402(p)(3)(B)(iii) and 40 CFR section 122.26(d)(2)(iv) which, in part, establishes the MEP standard and allows the state to include provisions appropriate for the control of pollutants.

Section XI of the Order describes categories of personnel that must receive training and a minimum training curriculum for each category. Refresher training must be given once every two years instead of once each year; initial training for new employees must still be given within 6 months of hire. Refresher training frequencies have been reduced because existing employees have accumulated training and experience during the past few permit terms. A significant body of institutional knowledge has likely been developed to informally reinforce the stormwater programs and to justify reducing the intensity of the training program.

The scope of personnel requiring training has been expanded to include staff, contractors, and vendors whose duties or responsibilities directly or indirectly affect the Permittees’ capacity to satisfy the requirements of this Order. For some Permittees, this may mean that additional personnel will require training. The purpose of this expansion is to better harmonize the Permittees’ internal departments and increase participation in the effort to reduce or eliminate pollution.

Section XI of the Order also now requires that the Permittees employ objective methods to individually evaluate trained personnel. It also now requires that training records be maintained for a minimum of three years. A registry or similar mechanism is also required to facilitate tracking and reporting for the Principal Permittees and to permit training records to follow staff that change employment between different Permittees. The training program must be reviewed and updated annually to achieve continual improvement. The Permittees may implement a single training program, individual programs, or some hybrid of the two.

Therefore, the review and update may occur collectively, coordinated by the Principal Permittee, or be performed individually by each Permittee according to how the training program is implemented.

XIV. RATIONALE FOR WATERSHED MANAGEMENT PLANS
A. Purpose of Watershed Management Plans
Section XII of the Order allows the Permittees to develop and implement Watershed Management Plans (WMPs). Participation in a WMP is a voluntary, alternative compliance option for Permittees that gives them the flexibility to implement the requirements of the Order on a watershed scale through customized strategies, control measures, and BMPs.

Specifically, the development and implementation of, and the Permittees’ compliance with, WMPs serves as an alternate method to comply with receiving water limitations in section VI (Receiving Water Limitations) and/or with WLAs that are expressed as WQBELs in section VII (Effluent Limitations and Discharge Specifications). Watershed Management Plans may only be used to determine compliance with these requirements when final compliance deadlines have not yet passed or where no final compliance deadline is specified. The WMPs must be approved by the Executive Officer, subject to public review.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 266 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
WMPs are new to the Order and were not included in prior permits. They were initially described in the Los Angeles Water Board’s Order R4-2012-0175. The State Water Board affirmed the use of WMPs as an alternative compliance path in Order WQ 2015-0075. In Order WQ 2015-0075, the State Water Board found that WMPs are “an appropriate alternative to immediate compliance with receiving water limitations”. (Order WQ 2015-0075, p.76.) In fact, the State Water Board directed all Regional Water Boards to consider WMPs for inclusion in their MS4 permits moving forward. (Id. at p. 51.) The incorporation of WMPs into the Order is therefore consistent with precedent set by the State Water Board in Order WQ 2015-0075.

The inclusion of WMPs is also consistent with federal regulations that support the development of permit conditions, as well as the implementation of stormwater management programs, at a watershed scale. (See 40 CFR §§ 122.26(a)(3)(ii), 122.26(a)(3)(v), and 122.26(d)(2)(iv).) USEPA has issued a Watershed-Based NPDES Permitting Policy Statement (USEPA, 2003) that defines watershed-based permitting as an approach that produces NPDES permits that are issued to point sources on a geographic or watershed basis. In this policy statement, USEPA explains that “[t]he utility of this tool relies heavily on a detailed, integrated, and inclusive watershed planning process.” USEPA identifies a number of important benefits of watershed permitting, including more environmentally effective results; the ability to emphasize measuring the effectiveness of targeted actions on improvements in water quality; reduced cost of improving the quality of the nation’s waters; and more effective implementation of watershed plans, including TMDLs, among others.

Additionally, Public Law 115-436, the Water Infrastructure Improvement Act (January 14, 2019), enacted section 402(s) of the CWA authorizing integrated plans that address both municipal wastewater and stormwater management as a potential compliance path that may be incorporated into an NPDES permit. Integrated planning is designed to help municipalities identify efficiencies in implementing requirements that arise from distinct permitting programs, particularly how best to make capital investments (Integrated Municipal Stormwater and Wastewater Planning Approach Framework, EPA, June 5, 2012). Under this law, an integrated plan can be used to implement any requirements relating to “a combined sewer overflow,” “a capacity, management, operation, and maintenance program for sanitary sewer collection systems,” “a municipal stormwater discharge,” “a municipal wastewater discharge,” and a “water quality-based effluent limitation to implement an applicable wasteload allocation in a total maximum daily load.” The integrated plan can include “a schedule of compliance, under which actions taken to meet any applicable water quality based effluent limitation may be implemented” and “the implementation of projects, including innovative projects, to reclaim, recycle, or reuse water; and green infrastructure.” (33 USC § 1342(s).) The integrated planning approach does not relax or change regulatory permitting standards, but rather recognizes existing flexibilities in the CWA to sequence and schedule projects that may be relevant to multiple permitting programs. (Id. at subd. (s)(5).) While the WMPs authorized in the Order are not “integrated plans” as defined in CWA section 402(s), these watershed level plans share many of the same underlying principles and advance the same goals that prompted the Santa Ana Water Board to adopt a watershed-based permitting approach for the Order.

A watershed-based permitting approach is also supported by a number of state and nationwide studies regarding MS4 pollution (Little Hoover Commission, Clearer Structure, Cleaner Water: Improving Performance and Outcomes at the State Water Boards (January 22, 2009).) In 2008, the National Research Council published a report stating: “The course of action most likely to check and reverse degradation of the nation’s aquatic resources would be to base all storm water and other wastewater discharge permits on watershed boundaries

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 267 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
instead of political boundaries.” (National Research Council, Urban Stormwater Management in the U.S. (October 15, 2008).) The report acknowledged the challenges of such an approach would include “the inevitable limits of an urban municipality’s authority within a larger watershed” but said the approach would be “essential” even though it would likely take years to implement.

This Order allows the Permittees to voluntarily develop and implement WMPs, either individually or collaboratively, to implement Order requirements on a watershed scale.

Permittees may do so through customized strategies, activities, and milestones. This approach allows the Permittees to address crucial differences in the circumstances of the impairments for the different waterbody-pollutant combinations. If Permittees do not comply with the requirements of section XII, Permittees must comply with receiving water limitations in section VI and the WQBELs in WQBELs in section VII of the Order.

B. Watershed Management Plan Development and Contents
Timelines to submit a WMP to the Santa Ana Water Board for approval are indicated in section XII.A of the Order. The schedule for development of the WMP must be as short as practicable.

Permittees that prepare WMPs proactively at the start of the permit term will be deemed in compliance with the applicable receiving water limitation and/or WQBEL for that waterbodypollutant combination for a period of no longer than 24 months. Such a limited time “safe harbor” during WMP preparation was sanctioned by the State Water Board in Order WQ 2015- 0075. (See pp. 49-50.) To encourage community and stakeholder involvement in the development of the WMPs, the Order requires that draft WMPs are made available for public review prior to approval by the Santa Ana Water Board or Executive Officer on behalf of the Santa Ana Water Board.

The goal of WMPs is to facilitate cooperative implementation of strategies, control measures, and BMPs among Permittees and, potentially, other partners within a watershed to control discharges of pollutants from the MS4 to levels that attain WQBELs and do not cause or contribute to exceedances of receiving water limitations, and which also implement the MEP standard for stormwater discharges and the requirement to effectively prohibit non-stormwater discharges through the MS4 to receiving waters. Each WMP must:
· Prioritize water quality issues resulting from stormwater and non-stormwater discharges through the MS4 to receiving waters within each watershed covered, · Identify and implement strategies, control measures, and BMPs to achieve applicable WQBELs and/or receiving water limitations, consistent with applicable compliance schedules in the Order,
· Execute an integrated monitoring and assessment program to determine progress towards achieving applicable limitations, and
· Modify strategies, control measures, and BMPs as necessary based on analysis of monitoring data collected pursuant to the MRP to ensure that applicable WQBELs and receiving water limitations and other milestones set forth in the WMP will be achieved.

The WMP must include an evaluation of existing water quality conditions, including characterization of stormwater and non-stormwater discharges from the MS4 and receiving water quality, consistent with 40 CFR sections 122.26(d)(1)(iv) and 122.26(d)(2)(iii). This effort is to support identification, prioritization, and sequencing of management actions.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 268 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Permittees must identify the water quality priorities within each watershed that will be addressed by the WMP consistent with 40 CFR section 122.26(d)(2)(iv) and Section XII.B of the Order. At a minimum, these priorities must include achieving some or all applicable WQBELs and/or receiving water limitations established pursuant to TMDLs and included in the Order. Highest priority must be given to waterbody-pollutant combinations for which a WQBEL is in place with interim and/or final compliance deadlines that occur within the permit term.

Permittees must identify strategies, control measures, and BMPs to implement through their jurisdictional stormwater management programs, or collectively on a watershed scale, with the goal of creating an efficient program to focus individual and collective resources on watershed priorities, particularly achieving WQBELs and receiving water limitations addressed by the WMP.

As part of the WMP, Permittees must conduct a Reasonable Assurance Analysis (RAA) for drainage areas not addressed by retaining the runoff volume of the 85th percentile, 24-hour storm event. The RAA includes an assessment (through quantitative analysis or modeling) to demonstrate that the activities (i.e., BMPs) and structural control measures identified as watershed control measures will achieve applicable WQBELs and/or receiving water limitations with compliance deadlines during the permit term. The objective of the RAA is to demonstrate the ability of the WMP to assure that Permittees’ MS4 discharges achieve WQBELs by the applicable compliance deadlines and do not cause or contribute to exceedances of receiving water limitations.

Consistent with 40 CFR section 122.47(a), schedules must be developed for both the strategies, control measures and BMPs to be implemented by each individual Permittee within its jurisdiction and for those that will be implemented by multiple Permittees on a watershed scale. The schedule is to be made up of a minimum of three critical milestones, an unspecified number of non-critical milestones, and a final compliance deadline. The final compliance deadline must be as short as possible and must not exceed the deadline for attainment of the TMDL WLA for that pollutant-waterbody combination found in the Basin Plan. Permittees are subject to potential enforcement action if they fail to meet critical milestones and the final deadline, but not for non-critical milestones. The Executive Officer is authorized to assign critical milestones as part of conditions of approval for a WMP. This will help motivate meaningful progress in implementing the WMP.

Together, critical, and non-critical milestones must be sufficiently detailed to allow early detection of deviations in the schedule. Allowing for non-critical milestones allows Permittees to disclose complex steps in the implementation process without creating undue enforcement liability. Section XII includes other requirements for disclosure of risks to the successful attainment of receiving water limitations and WQBELs. Along with other reporting requirements, this is intended to promote clear and timely communication of the Permittees’ progress.

Where compliance schedules are not available (e.g., final TMDL deadlines have passed), Permittees may request a Time Schedule Order (TSO) as discussed in section XII.E.

Permittees may propose a schedule in the WMP that is longer than the compliance schedule set by the TMDL if a TSO has been approved by the Santa Ana Water Board for a waterbodypollutant combination in that TMDL.

C. Implementation and Termination of a Watershed Management Plan

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 269 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Each Permittee must implement the WMP immediately after a determination by the Santa Ana Water Board that the WMP meets the requirements of the Order and is approved.

The approval of a WMP by the Santa Ana Water Board means that the responsible Permittees will be deemed in compliance with section VI (Receiving Water Limitations) and section VII (Effluent Limitations and Discharge Specifications) for those pollutant-waterbody combinations to which that approval applies, provided that the WMP is implemented and that the final compliance deadline specified in the Basin Plan has not passed. Given the significant time and effort required to develop and implement a WMP, the Order allows Permittees to be deemed in compliance with WQBEL(s) and/or receiving water limitation(s), irrespective of actual attainment of the applicable limitation. Permittees are only deemed in compliance with these limitations up until the final deadline for the achievement of the relevant WQBEL(s) and/or receiving water limitation(s) in the WMP has passed.

WMPs may not include final TMDL compliance deadlines later than the deadlines specified in the Basin Plan unless a TSO has been approved by the Santa Ana Water Board for a waterbody-pollutant combination in that TMDL, or unless the Permittee is retaining all nonstormwater runoff and the volume of stormwater runoff from the 85th percentile 24- hour storm, and the Permittee is continuing to engage in monitoring and adaptive management through an approved WMP. The exception made for the 85th percentile, 24-hour storm retention was sanctioned by the State Water Board in Order WQ 2015-0075. Order WQ 2015- 0075 found that this stormwater retention approach would achieve compliance if implemented along with ”continued planning, monitoring, and adaptive management.” (Id. at pp. 46.) Order WQ-2015-0075 supports the stormwater retention approach as a means of compliance with RWLs and/or WQBELs because “public projects requiring investment of this magnitude are unlikely to be carried out without a commitment from the water boards that Permittees will be considered in compliance even if the resulting improvement in water quality does not rise all the way to complete achievement of the final WQBELs and other TMDL specific limitations.” (Id. at pp. 44-45.)
Permittees must implement an adaptive management process (or iterative process) for each approved WMP. After a final WMP is approved, responsible Permittees must reevaluate the conclusions of Reasonable Assurance Analyses biennially based on new information, information that was previously unknown, and the degree of progress in implementing the WMP. Based on the results of the adaptive management process, the Permittee(s) must propose WMP modifications necessary to improve the effectiveness of the WMP, including but not limited to new compliance deadlines and interim requirements (except for those final compliance deadlines established in a TMDL) and new or substitute watershed control measures.

The Order includes a process for terminating a WMP and consequently requiring Permittees to comply with WQBELs and receiving water limitations for that waterbody-pollutant combination. If the Executive Officer determines that a Permittee has failed to comply with any of the provisions in this section related to developing a WMP, or to meet the critical milestones in a final WMP, the Executive Officer may provide written Notice of Violation (NOV) to the responsible Permittees. The Executive Officer may determine that the responsible Permittee has constructively abandoned a WMP if the deficiencies identified in the NOV are not addressed within 90 days. Upon concluding that the WMP has been constructively abandoned, the Executive Officer will provide written notice to the responsible Permittee(s) that the WMP is terminated and inform the Permittee(s) of their responsibility to immediately comply with the applicable receiving water limitations and WQBELs.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 270 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
XV. RATIONALE FOR MUNICIPAL INSPECTIONS OF CONSTRUCTION,

INDUSTRIAL, AND COMMERCIAL SITES
Section XIII of the Order continues previous permits’ requirements for inspections of construction, commercial, and industrial sites within each Permittees’ jurisdiction with some modifications. The requirements are supported by 40 CFR section 122.26(d)(2)(iv)(A)-(C), which generally require programs to implement control measures for pollutants in runoff from construction, commercial, and industrial sites.

The scope of what constitutes a construction site has not changed. However, Permittees are now only required to inspect construction sites where the actual or expected duration exceeds two weeks. This modification has been made recognizing that many construction projects may begin and conclude without being subject to a rain event and before Permittees’ staff can inspect them. This modification is intended to allow Permittees to prioritize projects that have a longer duration. The Permittees must necessarily track all construction sites to identify projects whose duration exceeds two weeks and consequently require inspection.

Mobile businesses have been excluded from the industrial and commercial business inventories. Instead, these businesses are addressed through the Permittees’ IDDE and public education programs. The reason for their exclusion is because it is impractical to impose a regular inspection program on the Permittees for businesses whose times or locations are difficult to predict.

The Order continues requirements for industrial facilities to be classified into three categories:
“high priority”, “medium priority”, and “low priority”. For industrial sites, “high priority” sites must be inspected once per year; “medium priority” sites must be inspected once every two years; and “low priority” sites must be inspected once per permit term (5 years).

The Order provides the Permittees substantial discretion to amend their protocol and select the type of inspections and the related level of effort that are suitable to the individual characteristics of a site. This is intended to encourage Permittees to use their experience and observations to evaluate a site’s risk to water quality.

XVI. RATIONALE FOR MUNICIPAL FACILITIES/ACTIVITIES PROVISIONS The requirements in section XIV of the Order for the municipal facilities/activities provisions are supported by 40 CFR sections 122.26(d)(2)(iv)(A)(1), (3), and (6). With some changes, the Order carries over similar provisions from prior orders. The provisions required the Permittees to conduct a systematic program of pollution control measures and best management practices for fixed facilities, field operations and drainage facilities, fertilizer and pesticide use, employee training, storm drain inspection and maintenance activities, and other related planning, inspection and maintenance programs.

The Order adds more specific requirements that each Permittee maintain an inventory of fixed facilities that are owned or controlled by the Permittee, which have the potential to discharge pollutants in runoff. The facilities must be categorized into high priority, medium priority, and low priority sites. The Order also adds a minimum inspection frequency for fixed facilities, but with flexibility for the Executive Officer to approve an alternate schedule. USEPA’s 2010 MS4 Permit Improvement Guide recommends an inventory that is similar to the requirements in the Order. (USEPA, MS4 Permit Improvement Guide (April 2010) pp. 67-69.)

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 271 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Permittees must also implement an effective program to prevent the discharge of pollutants from Permittees’ field activities and fixed facilities. This includes documentation of BMPs used to prevent or minimize the discharge of pollutants, written standard operating procedures (SOPs) for Permittees’ staff who engage in field activities, and activities at fixed facilities that have the potential to discharge pollutants in runoff, and a training program for such staff. There are also requirements relating to pesticide use.

Each municipal facility will require a set of control measures that depend on the nature of activities and the types of materials that are stored and used. Developing and maintaining a site-specific SOP for each facility will help to ensure that employees responsible for facility operation are aware of the stormwater controls required for the site.

XVII. RATIONALE FOR PROGRAM EFFECTIVENESS ASSESSMENTS PROVISIONS Section XV of the Order requires that each Permittee have a program in place to objectively assess the effectiveness of control measures/BMPs employed in each of the elements of their stormwater programs and pursue continual improvement. These requirements support a structured, iterative or adaptive management process. Each Permittee’s program must be documented in writing. The Permittees may develop a model program for effectiveness assessment.

These requirements set the expectation that common features of each of the Permittees’ programs will generally be assessed in a similar way, but there is no requirement that a completely uniform set of methods will be applied across each Permittee’s programs. The effectiveness assessment method should identify the program element or activity being assessed, the assessment management questions, the timeframe for the assessments, the expected outcome, the measures/metrics used to assess the outcome, and if any modifications to the effectiveness assessment approach are necessary.

As part of the program effectiveness assessment, the Permittee must have a hypothesis of the pollution process or a conceptual model. The development of conceptual models is the first step in developing more detailed quantitative models and eventually developing solutions.

Such models are called explanatory models. Explanatory models establish and communicate a baseline of understanding and form a rational basis for developing and testing hypotheses about a process. They can help identify parts of a process that are not well understood. They can also help identify opportunities where interventions or best management practices may be effective in getting a desired outcome.

A conceptual model or hypothesis may be a graphical representation, but simple models may be expressed as written narratives that express theories on the pollution process. The Permittees have expressed simple models in written narratives in their Annual Progress Reports.

As with the previous permits, Permittees are required to develop an inventory of control measures and BMPs, and where in the pollution process they are applied. This establishes a baseline condition and sets the context for monitoring and reporting results. Placing control measures and BMPs in relation to the pollution process can help identify imbalances and gaps. An imbalance may occur where control measures and BMPs disproportionately focus on prevention or treatment of pollution. A gap may occur where there is a missed opportunity to implement a control measure or BMP in the pollution process.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 272 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Permittees must have a system to objectively measure the performance of their control measures and best management practices or systems of measures and practices. This will include using performance metrics prescribed by this Order and measures that will need to be developed by the Permittees. While the performance metrics prescribed by this Order are enforceable if not achieved, performance metrics developed by the Permittees will not be enforceable. However, failure to implement the “iterative process” when voluntary performance metrics are not achieved will subject the Permittees to enforcement.

An objective assessment of the performance of a program can be quantitative or qualitative.

A quantitative assessment is one where the differences in outcomes are measured. A qualitative assessment is where the differences in outcomes can be perceived but are not or cannot be measured. An outcome can be objectively assessed as being better or worse than others, but the difference is not quantified. Qualitative assessments are sometimes measured using ordinal ranking systems such as “good”, “better”, “best”; A, B, C; “high”, “medium”, “low”; etc. Ranking systems should always be accompanied by objective definitions that make each category mutually exclusive, readily distinguishable, and repeatable among different observers.

An objective performance assessment should use direct measurements of the thing being measured where possible. However, this is not required. In some cases, indirect measurements may be necessary because the thing being measured is intangible (e.g., public confidence) or cannot be observed directly (e.g., public pollution preventing behaviors).

Indicators may be used as performance metrics in assessments. For example, public reports on illicit discharges may be used as an indicator of public engagement and awareness of water quality issues. However, indicators may be found faulty later on, for example, if a Permittee finds that complaints don’t come from a representative cross-section of residents.

Ultimately, Permittees are required to ensure that their performance metrics are representative.

Permittees must evaluate the validity of the program, which involves considering if the performance metrics are genuinely representative of what they are intended to measure. It also involves evaluating if the method used to measure outcomes is also valid. Permittees are encouraged to develop “S.M.A.R.T.” goals. S.M.A.R.T. goals are performance metrics that are Specific, Measurable, Attainable, Realistic, and Timely.

There are various resources which are widely available that describe how to develop S.M.A.R.T. goals. S.M.A.R.T. goals are known by other names, including, measurable goals, performance metrics, performance standards, targets, and objectives. Performance metrics, the term used most widely in this document, should align with more general goals found in this Order or, otherwise developed by the Permittees to be valid. Valid performance metrics should have certain basic characteristics. The performance metric should:

1. Have a need or purpose.

2. Provide useful information.

3. Focus on a target or objective.

4. Be measurable with reasonable accuracy and verifiable.

5. Reflect the true status of the activity or project.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 273 of 320 Fact Sheet
Santa Ana Regional MS4 Permit

6. Not be subject to alternative conflicting interpretation.

7. Support proactive and adaptive management.

8. Assist in evaluating the likelihood of success or failure.

9. Be accepted by internal and external stakeholders as a tool for informed decisionmaking43 .

The purpose of pursuing performance metrics is to help Permittees develop an understanding of what combination of tactics are most effective to meet the Permit goals.

XVIII. RATIONALE FOR MONITORING AND REPORTING PROGRAM
Monitoring and Reporting Program (MRP) No. R8-2024-0001 can be found in Attachment C to the Order. It contains requirements for both water quality monitoring, annual reporting, and for program effectiveness assessments. The requirements of the MRP are incorporated by reference into the Order and are enforceable.

Sections 308(a) and 402(a)(2) of the federal Clean Water Act, and 40 CFR sections 122.41(h), (j)-(l), 122.44(i), and 122.48 require that all NPDES permits specify monitoring and reporting requirements and establish substantive monitoring and reporting requirements for NPDES permits. Federal regulations applicable to large and medium MS4s also specify additional monitoring and reporting requirements. (40 CFR §§ 122.26(d)(2)(i)(F) & (d)(2)(iii)(D), 122.42(c).) Water Code section 13383 further authorizes the Santa Ana Water Board to establish monitoring, inspection, entry, reporting, and recordkeeping requirements.

The MRP contains requirements for both dry weather and wet weather monitoring as part of a Program Monitoring and Reporting Plan (PMRP). The dry weather monitoring requirements are based on the requirements of 40 CFR section 122.26(d)(1)(iv)(D), (d)(1)(v)(B), and (d)(2)(iv)(B). The wet weather monitoring requirements are based on the requirements of 40 CFR section 122.26(d)(2)(iii), (d)(2)(iii)(A) and (d)(2)(iii)(A)(1) through (4); and 40 CFR section 122.21(g)(7)(i) through (ii). Requirements related to monitoring and reporting pollutant loads are consistent with 40 CFR section 122.26(d)(2)(iii)(B) and (d)(2)(v). Requirements for receiving waters monitoring are consistent with federal requirements to report “water quality improvements or degradation” according to 40 CFR section 122.42(c)(7). Annual reporting requirements are consistent with 40 CFR section 122.42(c).

The MRP requires monitoring to address illicit discharges/illicit connections, water quality standards attainment or non-attainment, and compliance with WLAs expressed as WQBELs in Appendices 2 through 13.

The Permittees have been implementing water quality monitoring programs for several decades. The programs, in one form or another, have served multiple purposes beyond compliance with MS4 permit requirements. The Order essentially requires re-documentation of the current programs and provides the Permittees with an opportunity to make improvements in the process. The MRP is purposefully written without some of the detail found in the Permittees’ previous monitoring program requirements. The purpose is to provide 43 Kerzner, H. (2013). Project management: A systems approach to planning, scheduling, and controlling (11th ed.). Wiley, Hoboken NJ.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 274 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
flexibility to the Permittees as they prepare new Program Monitoring and Reporting Plans (PMRPs). The Executive Officer is authorized to amend the PMRP, particularly if important program improvements are hindered by the PMRP and impose conditions of approval. The new monitoring plans will be subject to public review and the Executive Officer’s review and approval.

The requirements in the Order and the MRP for effectiveness assessments are consistent with 40 CFR section 122.42(c)(1), which requires reports of the “status of implementing the components of the stormwater management program that are established as permit conditions.” This includes use of the “iterative process” as well as other “management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants” as described in CWA section 402(p)(3)(B)(iii).

The MRP requirements allow the Permittees to use monitoring work performed by others to substitute for work required by the MRP. The MRP requirements also allow the Permittees to supplement their own monitoring work with work performed by others to improve any related analyses. The substituted or supplemental monitoring work must meet the requirements of the MRP to be valid. The MRP has been written with the intent of encouraging the Permittees’ participation in statewide, national, regional, or local monitoring programs. This will help avoid duplication of work, improve related analyses of monitoring results, promote cooperation among other NPDES permittees and other institutions interested in water quality, and generally strengthen the body of scientific and technical knowledge of water quality. In this spirit, Provision XV.2.c. of the Order requires the Permittees to make the results of field and laboratory analyses available to the public.

XIX. RATIONALE FOR STANDARD PROVISIONS
Standard Provisions apply to all NPDES permits in accordance with 40 CFR section 122.41.

Standard Provisions and additional conditions applicable to specified categories of permits in accordance with 40 CFR section 122.42, are provided in Attachment F. Dischargers must comply with all Standard Provisions and with those additional conditions that are applicable under section 122.42.

XX. RATIONALE FOR REOPENER AND PERMIT MODIFICATION
The provisions in section XVIII of the Order are based on 40 CFR sections 122.44, 122.62, 122.63, 122.64, 124.5, 125.62, and 125.64, and are also largely carried over from the previous permits. The Santa Ana Water Board may reopen the permit to modify permit conditions and requirements, as well as revoke, reissue, or terminate in accordance with federal regulations.

XXI. WATER CODE SECTION 13241
Water Code section 13241 requires the Santa Ana Water Board to consider the following factors in the adoption of water quality objectives.
(a) Past, present, and probable future beneficial uses of water. (b) Environmental characteristics of the hydrographic unit under consideration, including the quality of water available thereto.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 275 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
(c) Water quality conditions that could reasonably be achieved through the coordinated control of all factors which affect water quality in the area. (d) Economic considerations.
(e) The need for developing housing within the region.
(f) The need to develop and use recycled water.

The Santa Ana Water Board is not establishing water quality objectives in the Order.

However, Water Code section 13263 requires the Santa Ana Water Board to take into consideration the provisions of Water Code section 13241 in adopting waste discharge requirements, when such requirements are more stringent than what federal law requires. (City of Burbank v. State Water Resources Control Bd. (2005) 35 Cal. 4th 613.) Consideration of section 13241 factors cannot justify permit conditions that are less stringent than what federal law requires. (Id. at 626.) The manner in which the Santa Ana Water Board considers section 13241 factors is within the board’s discretion. (City of Duarte v. State Water Resources Control Board (2021) 60 Cal.App.5th 258, 273, as modified on denial of reh'g (Feb. 19, 2021), review denied (Apr. 28, 2021), citing City of Arcadia v. State Water Resources Control Bd. (2010) 191 Cal.App.4th 156, 177, and City of Arcadia v. State Water Resources Control Bd. (2006) 135 Cal.App.4th 1392, 1415.) The Santa Ana Water Board finds that each of the requirements in the Order are not more stringent than what federal law requires for the control of MS4 discharges of pollutants in the Santa Ana Region. The Santa Ana Water Board makes additional findings with respect to specific program areas throughout the Fact Sheet.

Clean Water Act section 402(p)(3)(B) requires MS4 permits to include requirements to effectively prohibit non-stormwater discharges through the MS4 to receiving waters, as well as “controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants.” The permitting agency, be it the Santa Ana Water Board or U.S. EPA, must therefore include provisions when it finds it is appropriate to do so and to exercise its discretion to determine what permit conditions are necessary to control pollutants in a specific geographic area.

MS4 discharges in the Santa Ana Region are a continuing and significant source of pollutants to receiving waters, many of them impaired. As such, the Santa Ana Water Board finds that inclusion of all of the requirements in the Order are necessary and appropriate to control MS4 discharges in the Santa Ana Region. These requirements include but are not limited to requirements for non-stormwater discharges, technology and water quality-based effluent limitations, TMDLs, receiving water limitations, stormwater management program minimum control measures, and monitoring and reporting to ensure that the requirements of the Order are being met.

To the extent the requirements in the Order may be more specific or detailed than those enumerated in federal regulations under 40 CFR § 122.26 or in U.S. EPA guidance, the requirements have been designed to be consistent with and within the federal statutory mandates described in Clean Water Act section 402(p)(3)(B) and the related federal regulations and guidance. Consistent with federal law, all the requirements in the Order could

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 276 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
have been included in a permit adopted by U.S. EPA in the absence of California’s delegated authority to issue NPDES permits. (See Defenders of Wildlife v. Browner (9th Cir. 1999) 191 F.3d 1159, 1166.) Each of the requirements in the Order, especially when implemented together, constitutes the critical means towards achieving the requirements and goals of the Clean Water Act. The discussion above provides the rationale for each section of the permit, including citations to federal authority.

The inclusion of numeric Water Quality-Based Effluent Limitations (WQBELs) in this Order (e.g., WLAs and related TMDL requirements) does not cause this Order to be more stringent than federal law. This is discussed further in Section IX.B of this Fact Sheet.

Similarly, the Santa Ana Water Board is not required to consider the factors in Water Code section 13241 to adopt permit requirements necessary for the effective prohibition of nonstormwater discharges into the MS4; or for controls necessary to reduce the discharge of pollutants in stormwater to the MEP; or other provisions that the Santa Ana Water Board has determined appropriate. These general requirements are required by federal law.

This Order includes monitoring and reporting requirements that are designed to demonstrate that the Permittees are complying with the municipal stormwater requirements of the CWA.

CWA section 308(a) and 40 CFR section 122.41(h), (j) through (l); 122.44(i); and section 122.48 require that NPDES permits specify monitoring and reporting requirements.

Monitoring and reporting requirements are also required by 40 CFR sections 122.26(d)(1)(iv)(D); 122.26(d)(1)(v)(B); 122.26(d)(2)(i)(F); 122.26(d)(2)(iii)(D); 122.26(d)(2)(iv)(B)(2); and 122.42(c).

Therefore, since the Board determines that each of the requirements in the Order are not more stringent than what federal law requires, there is no legal requirement for the Board to consider the factors of California Water Code section 13241.

Notwithstanding the above, the Santa Ana Water Board has considered the factors set forth in California Water Code section 13241 in issuing the Order. The Board’s consideration of each of the factors is provided below. The Board has also considered all the evidence that has been presented to the Board regarding section 13241 factors in issuing the Order. This includes specific costs of compliance information presented to the Board by Permittees and stakeholders.

Having considered the factors in California Water Code section 13241, the Santa Ana Water Board finds that the requirements in the Order are necessary to ensure the reasonable protection of beneficial uses of waterbodies in the Santa Ana Region and the prevention of nuisance. None of the factors of section 13241, including costs of compliance, is sufficient to justify failing to protect those beneficial uses. Nor is it sufficient to justify omitting any requirement in the Order, as the Board finds that doing so would unreasonably affect the designated beneficial uses of the region’s waters. Additionally, it would be wholly inconsistent with federal requirements not to include requirements in the Order that the Board has deemed necessary for the control of MS4 discharges in the Santa Ana Region. Where appropriate, the Board has provided Permittees with additional time to implement control measures to achieve final WQBELs and/or receiving water limitations. In addition, the Board has provided significant flexibility for Permittees to choose how to implement the requirements of the Order, including by working with other Permittees to implement cost-effective control measures. The Order allows Permittees the flexibility to address critical water quality priorities, namely discharges to waters subject to TMDLs. The Order aims to do so in a focused and costPage 278 of 563

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 277 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
effective manner while maintaining the level of water quality protection mandated by the Clean Water Act.

In addition, the Office of Research, Planning, and Performance (ORPP) is preparing guidance in response to a March 2018 Audit Report of the State Water Board by the Governor’s Office.

The report suggested that the Water Boards have not adequately considered the cost of implementing pollution control requirements.

A. Past, Present, and Probable Future Beneficial Uses of Water Chapter 3 of the Basin Plan identifies existing and potential beneficial uses for surface water bodies in the Santa Ana Region, which are the receiving waters for MS4 discharges. The Basin Plan notes that a “potential” beneficial use is the same as a “probable future” beneficial use for purposes of 13241 factors. A potential beneficial use may be established because plans already exist to put the water to that use or because conditions, such as location and demand, make such future use likely. The establishment of a potential beneficial use protects the quality of that water for potential future use. More information about beneficial uses is available in section IV.D of this Fact Sheet.

Pollutants in discharges from MS4s have damaging effects on both human health and aquatic and riparian ecosystems. Water quality assessments conducted by the Santa Ana Water Board have identified impairment of beneficial uses of water bodies in the Santa Ana Region.

Pollutants in MS4 discharges cause or contribute to many of these impairments. As a result, there are beach postings, fish consumption advisories, ecosystem and recreational impacts from pathogens, trash and debris, and toxic conditions for aquatic life, among others. Twelve TMDLs established by the Santa Ana Water Board and U.S. EPA identify MS4 discharges as one of the sources causing or contributing to impairments of beneficial uses in the Santa Ana Region. The requirements of the Order are necessary to protect and restore the past, present, and probable future beneficial uses of surface waters in the region.

B. Environmental Characteristics of the Hydrographic Unit Under Consideration, Including the Quality of Water Available Thereto
The hydrologic unit under consideration is the Santa Ana River Basin, which is broken down into subbasins, watersheds, and subwatersheds. Environmental characteristics of the subbasins and watersheds covered by the Order, including the quality of water available, are discussed in sections III, IV.F, and IV.G of this Fact Sheet. Additional information on impaired waters in the Santa Ana Region can be found in the State’s Clean Water Act section 303(d) List of impaired waters:
https://www.waterboards.ca.gov/water_issues/programs/water_quality_assessment/.

C. Water Quality Conditions that Could Reasonably be Achieved Through the Coordinated Control of All Factors Which Affect Water Quality in the Area Subsection (c) of section 13241 provides for the consideration of “[w]ater quality conditions that could reasonably be achieved through the coordinated control of all factors which affect water quality in the area.” As discussed below under Need for Developing Housing in the Region and the Need for Recycled Water, the Order takes a coordinated approach to controlling pollutant discharges from MS4s. The coordinated approach is defined by the

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 278 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
WMP requirements in the Order. WMPs take into account all factors affecting water quality through the source assessment, as required in Section XII.B.2.

The Santa Ana Water Board considers water quality conditions that could reasonably be achieved through the coordinated control of all factors that affect water quality, when establishing water quality objectives, TMDLs, and TMDL programs of implementation in its Basin Plan. This Order implements the Basin Plan and other applicable water quality control plans. Therefore, this Order considers water quality conditions that could reasonably be achieved (i.e. water quality objectives) by incorporating the water quality objectives established in those plans.

The Santa Ana Water Board has established and incorporated TMDLs in the Basin Plan.

As discussed in section IX.B of this Fact Sheet, the Santa Ana Water Board implements the TMDLs, in part, by incorporating the WLAs and other requirements as WQBELs in the Order to achieve water quality objectives.

The Santa Ana Water Board finds that water quality conditions necessary to support beneficial uses are reasonably achievable through coordinated control of all factors which affect water quality. Where MS4 discharges are a significant factor, compliance with the requirements of the Order, alongside control of all other controllable factors, is necessary to achieve water quality conditions that support beneficial uses. This coordinated approach has been demonstrated by successful implementation of TMDLs in the Santa Ana Region.

The TMDL for sediment in upper Newport Bay and Reaches 1 and 2 of San Diego Creek provides an example of the achievability of water quality objectives through coordinated control of all factors affecting water quality. The waterbodies were listed as impaired by sediment loads from agriculture, urbanization, and construction grading activities (Chapter 6 of the Basin Plan). The Santa Ana Water Board adopted a TMDL to control sediment sources in 1998. The TMDL required coordinated control of all sediment discharges to Newport Bay and its tributaries until the water quality standards were met. Stakeholders in the watershed collaborated to develop and implement various measures to reduce sediment transport. These measures included development and implementation of grading ordinances, erosion/siltation control plans, and the construction general permit to control sediment from construction sources, and resource conservation plans for agricultural sources. Further measures included maintenance of in-channel sediment basins in San Diego Creek, maintenance of retarding basins in the upper watershed foothills, periodic scour studies, sediment monitoring, and the Upper Newport Bay Ecosystem Restoration Project. As a result, the 10-year running average of sediment load has decreased steadily since first computed in 2010. In their 2021-22 Annual Report, Permittees reported the 10- year annual average sediment load is well below the established target in the TMDL44 .

The TMDL for Nitrogen and Phosphorus in Newport Bay and San Diego Creek is another example of the achievability of water quality objectives through coordinated control of all factors affecting water quality. The TMDL was adopted in 1999 following seasonal algal blooms which created aesthetic and recreational nuisance and may have harmed wildlife (Chapter 6 of the Basin Plan). Agriculture, commercial nurseries, and urban runoff were identified as the main nutrient sources in the watershed. The Santa Ana Water Board adopted individual WDRs for the nurseries, resulting in significant reductions in their 44 Newport Bay Watershed Sediment TMDL, 2021-22 Annual Report. Orange County Public Works. February 2023

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 279 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
nutrient load contributions (Chapter 6 of the Basin Plan). MS4 stakeholders have reduced nutrients loads by implementing:
· Treatment control measures such as constructed wetlands and biofilters · Volume reduction measures such as infiltration basins · Source control measures such as public education
In their 2021-22 Annual Report, Permittees reported seven of eight TMDL targets for Nitrogen and Phosphorus were met45.

D. Economic Considerations
Section 13241(d), when applicable, requires the Santa Ana Water Board to address economic considerations. For waste discharge requirements that serve as NPDES permits, this requirement only applies to those provisions that are more stringent than federal law. (City of Burbank v. State Water Resources Control Bd. (2005) 35 Cal. 4th 613.) The Santa Ana Water Board has nevertheless not limited its discussion of economic considerations to those provisions that are more stringent than what federal law requires.

In considering economics, it is not necessary for the Santa Ana Water Board to perform a cost-benefit analysis or other formal economic analyses. Performing a formal economic analysis is not currently practical. This is principally because of the lack of comprehensive or sufficiently reliable economic data on costs. Calculating the value of benefits is typically more difficult because benefits tend to be intangible. Methods for calculating benefits, such as surveys to estimate the recreational value of a day at the beach or the intrinsic value of wildlife, are infrequently performed and costly. However, the Santa Ana Water Board will consider what limited economic information is available.

The USEPA, the State Water Board, and the regional water quality control boards have attempted to evaluate the costs and benefits of municipal stormwater programs. The resulting studies show a large variability in reported costs and that there is difficulty in obtaining reliable cost information.

In 1999, the USEPA summarized the conclusions of multiple studies performed to determine the cost of stormwater management programs as part of its Phase II expansion of the NPDES stormwater program46
. The USEPA determined that the range of benefits from its Phase II expansion exceeds the range of regulatory costs. As part of their analysis, the USEPA reported that, based on appropriate cost data provided by 26 MS4 operators subject to Phase I, the average annual program costs were $ 16.30 per household (2022 dollars)47. The USEPA also reported that the average annual Phase II program costs were $16.45 per household (2022 dollars), comparable to per household costs of the Phase I program. 452021-22 Newport Bay Nutrient TMDL Annual Data Report. Orange County Public Works. December 2022 46 Federal Register/Vol. 64 No. 235/Wednesday, December 8, 1999/Rules and Regulations. P. 68791-68792. 47 USEPA’s cost estimates should be regarded as gross indicators of compliance costs, not actual compliance costs. See Government Accountability Office, May 2007. Further Implementation and Better Cost Data Needed to Determine Impact of EPA’s Storm Water Program on Communities. GAO-07-479.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 280 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
In 2003, staff of the Los Angeles Regional Water Quality Control Board performed a study of Phase I MS4 program costs48. Self-reported cost data provided in the MS4 operators’ annual reports was used. The average annual cost in Los Angeles County was estimated to be $12.50 per household (2002 dollars) which equates to $20.33 in 2022 dollars.

In 2005, the State Water Board commissioned a study by the California State University, Sacramento to assess costs of the Phase I MS4 program throughout the state49 . The annual
cost ranged from $18 to $46 per household (2005 dollars), which equates to $28.01 to $71.59 in 2022 dollars.

For comparison purposes, the per household cost information above have been adjusted for inflation using the United States Bureau of Labor Statistics’ Consumer Price Index Calculator.

All values were adjusted to 2022 dollars. The results are summarized in Table D.2 below.

Table D.2: Comparison of Estimates of Annual MS4 Program Costs (per household)
Study Reported Value(s) Inflation-Adjusted Value
(2022 dollars)
USEPA, 1999 $9.08 (Phase I)
$9.16 (Phase II)
$16.40 (Phase I)
$16.55 (Phase II)
Los Angeles Regional Water
Quality Control Board, 2003 $12.50 $20.42
State Water Resources
Control Board, 2005 $18 to $46 $28.01 to $71.59
An economic analysis of the cost of the Phase I program could involve a comparison of the MS4 operators’ costs with and without the Phase I program. The result would be marginal costs. Many of the reported Phase I program costs are not attributed solely to the program.

In many cases, program elements such as street sweeping and litter control are services that have been performed by the Permittees long before they were required by any Clean Water Act permit.

Therefore, the actual costs of the Phase I program for a Permittee are a portion of the reported costs. The State Water Board’s 2005 study, discussed earlier, estimated that 38% of the reported program costs could be fully attributed to the MS4 permits. The remainder was attributed to the costs of pre-existing services provided by the Permittees.50 48 Los Angeles Water Quality Control Board, 2003. Review and Analysis of Budget Data Submitted by the Permittees for Fiscal Years 2000-2003. P. 2.
49 State Water Resources Control Board, 2005. NPDES Stormwater Cost Survey. p. ii. 50 Id., p. 58.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 281 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Water Code section 13241 includes the need to consider “economic considerations” under certain circumstances. Economic considerations include both the costs of compliance and the economic benefit of protecting the beneficial uses of the waters of the State. There is some information available to estimate the costs of MS4 permits. However, information is not as available for estimating the benefits of protecting beneficial uses. Some beneficial uses, such as Industrial Process Supply, for example, may have their value more readily monetized because there is a well-established market for the resource.

For other beneficial uses, monetizing their value is much more difficult largely because the benefits are intangible. Certain techniques, such as Willingness to Pay and Travel Cost Analysis, have been employed by the USEPA at a national scale and in local studies in the Santa Ana Region, to value such things as beach recreation (a proxy for Water Contact and Non-Water Contact Recreation beneficial uses). But these techniques are more costly, typically requiring surveys of users or potential users. As a result, they are infrequently employed. However, two studies are useful in this analysis.

As part of their Phase II expansion of the NPDES program, the USEPA estimated that willingness to pay for improvements in freshwater quality for fishing and boating is approximately $158 to $210 per household (1998 dollars), which equates to $290.19 to $385.69 in 2022 dollars 51
. Another study, conducted by California State University, Sacramento, reported that the annual household willingness to pay for state-wide clean water is approximately $180 per household (2005 dollars), which equates to $280.14 in 2022 dollars52
.

Both above studies represent efforts to estimate the benefits of protecting beneficial uses.

Both estimates considerably exceed the annual per household costs of the MS4 programs summarized in Table EC-1 above. This is even more true if the marginal costs are a portion of the reported costs and are adjusted accordingly.

The Santa Ana Water Board also considered the cost of implementing Low-Impact Development (LID) treatment control measures to comply with the requirements of this Order.

In a 2013 study, the County of Orange partnered with the Construction Industry Coalition on Water Quality to develop estimates of the costs of incorporating different combinations of LID Control measure53. The study found that, assuming no technical infeasibility constraints, the least-cost LID treatment control measures are infiltration and biofiltration systems, regardless of the volume managed or project type. Where space is available within a project site (the case studies assumed 3% or less of the total site area) to install an infiltration basin or biofiltration system, the cost of installing these two types of LID treatment control measures is under $4 per gallon ($29.92 per cubic foot) and $2 per square foot of Total Impervious Area. In 2022 dollars, the values equate to $5.16 per gallon ($38.56 per cubic feet) and $2.58 per square foot of total impervious area. The analysis shows that infiltration systems are less expensive to install than biofiltration systems. This finding is generally consistent with published literature and reports on LID BMP costs in the US. 51 Ibid. p. 68793
52 State Water Resources Control Board, 2005. NPDES Storm Water Cost Survey. p. iv. 53 Mark Grey et al. 2013, The Cost of LID, www.stormh2O.com, March/April 2013 (accessed February 2022.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 282 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Santa Ana Water Board staff found similar information in a 2011 study from the Minnesota Pollution Control Agency54. Table D.3, below, presents the cost data on 69 BMP projects.

While both the USEPA and Minnesota reports cover a broad range of geographic and climatic conditions, they illustrate a wide variability in costs of different LID treatment control measures. The costs shown have been adjusted to 2023 dollars. 54 BARR, 2011. Best management practices construction costs, maintenance costs, and land requirements. Prepared for Minnesota Pollution Control Agency, June 2011.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 283 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Table D.3: Typical Cost of Stormwater LID Treatment Control Measures Stormwater BMP Dollars/Cubic Foot (cf) of Runoff
Large Wet Detention Basin $3.63 (treating more than 100,000 cf) Small Detention Basin $270.17 (treating less than 10,000 cf) Constructed Wetland $1.86
Infiltration Trench $20.50
Infiltration Basin $39.13
Bioretention Basin $27.96
Biofiltration Basin $108.07
Underground Infiltration $14.90
Pervious Pavement $29.81
In accordance with the Santa Ana Region’s previous MS4 Permits, Permittees reported their annual expenditures for compliance with stormwater requirements in their Annual Progress Reports. Table D.4 shows the Permittees’ expenditures (updated to December 2022 dollars) for the last 5 years as reported in the Annual Progress Reports. The expenditures are not comparable between counties due to the variability in population and geographic size of the jurisdictions, program elements, and compliance and accounting methods. Table D.4 shows the reported costs incurred by the Permittees during fiscal years 2014-15 through 2018-1955 .

The Riverside County expenditures for fiscal year 2014-2015 did not include expenditures for the cities of Norco and Riverside.
55 Annual Progress Reports from Counties of Orange, Riverside, and San Bernardino for 2014-15 through 2018-19.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 284 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Table D.4: Permittees’ Reported Expenditures Based on County Jurisdictions Expenditures by County in December 2022 dollars
Fiscal Year Riverside County Orange County San Bernardino County
2014-15 $20,294.91 K $197,859.30 K $58,404.25 K
2015-16 $38,346.34 K $202,124.22 K $24,831.36 K
2016-17 $33,501.56 K $204,543.73 K $204,607.01 K
2017-18 $43,360.24 K $171,653.09 K $224,185.16 K
2018-19 $34,762.77 K $169,888.21 K $233,277.60 K
A study conducted by USC/UCLA assessed the costs and benefits of implementing various approaches for achieving compliance with the MS4 Permits in Los Angeles Region56 . The
study found that source control systems would cost $3.22 billion but provide $6.44 billion in benefits. The study also found that treatment systems would cost $6.56 billion to $8.51 billion, while benefits could reach $20.71 billion. These values have been adjusted to 2022 dollars.

TMDL Compliance Costs
In 2001, USEPA estimated the annual costs of implementing TMDLs for 20,000 waterbodies across the country (EPA 841-D-01-003, August 1, 2001)57. The following table shows the estimated annual costs of implementation in 2022 dollars. 56 LARWQCB, 2004. Alternative Approaches to Stormwater Control 57 USEPA, 2001. The national costs of the total maximum daily load program (draft report). Office of Water (4503F), Washington DC 20460, EPA 841-D-01-003, August 1, 2001.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 285 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Table D.5: Adjusted USEPA Compliance Cost Estimates /Year Program Type Costs (2022 dollars) in Billions
Least Flexible58 $ 3.22- $ 7.28
Moderately Cost Effective59 $ 1.69 - $ 5.76
Most Cost Effective60 $ 0.24 - $ 0.40
In November 2010, USEPA estimated the annual cost of implementing the nutrient numeric TMDL in the State of Florida’s lakes and flowing waters to be between $60.5 Million to $108 Million dollars, which equates to annual cost of between $82.87 Million and $147.93 Million in 2022 dollars.

In 2005, the Office of Water Programs (OWP) at Sacramento State, the University of Southern California, the University of California Los Angeles (UCLA), the California State Water Resources Control Board (State Water Board), and the Regional Water Quality Control Boards (Regional Water Boards) surveyed six municipalities to estimate costs for compliance with permit requirements61. Currier et al. (2005) reported the survey results and found that communities spent between $25.15–$64.27 (2022 dollars) per household.

In a 2014 study, the Public Policy Institute of California estimated stormwater funding needs in the range of $1.17–$1.75 billion (2022 dollars) across the state62. The value was derived based on extrapolating detailed data for a few case study communities. Hanak et al. (2014) estimated costs to be between $638.12–$1,020.99 million (2022 dollars) annually across communities.
58 This scenario explores what costs to pollutant sources would result if the nation chose to restore the currently impaired waters under a TMDL program in which every source affecting an impaired water would be required to implement further control measures, rather than a more calibrated approach. 59 This scenario differs from the first scenario in that it assumes the use of a more careful TMDL process, including non-uniform and flexible allocation among sources to achieve cost effective reductions. 60 This scenario recognizes the possibility of reducing TMDL costs to point source dischargers through either additional “cost-effective wasteload allocations” or through trading, or both. 61 Currier, B.K., et al. 2005. NPDES Stormwater cost survey: final report. Office of Water Programs, California State University, Sacramento, Prepared for the California State Water Resources Control Board, January 2005.
62 Hanak, Ellen, Brian Gray, Jay Lund, David Mitchell, Caitrin Chappelle, Andrew Fahlund, Katrina Jessoe, et al. 2014. Paying for Water in California. Public Policy Institute of California

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 286 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
USEPA (May 2020) estimated the TMDL costs of compliance In California63. Spending by geographic Regions revealed noticeable trends in spending and data availability. The analysis aggregated data for MS4s in a region according to Regional Water Quality Control Board boundaries. The following table shows the regional expenditures:

Table D.6: Adjusted USEPA Compliance Cost Estimates per Region Regions Expenditures in Millions (2022 dollars)
Region 1 – North Coast $1.05
Region 2 – San Francisco Bay $8.27
Region 3 – Central Coast $5.77
Region 4 – Los Angeles $376.05
Region 5 – Central Valley $175.49
Region 6 – Lahontan Not Reported
Region 7 – Colorado River Basin $0.19
Region 8 – Santa Ana $162.96
Region 9 – San Diego $225.64
Total all Regions $965.18
The Los Angeles Water Board compiled the cost of complying with TMDL waste load allocations assigned to MS4 discharges in a staff memo titled “2020 Regional MS4 TMDL Compliance Costs,” dated July 17, 2020 (TMDL Staff Report Cost Memo). Using costs estimated during the establishment of TMDLs, the TMDL Staff Report Cost Memo estimated the total capital cost of implementing the 45 TMDLs included in the Order to be $5.75 Billion with total annual operation and maintenance (O&M) costs of $482.29 Million. The total 20- year costs add up to $15.62 Billion in 2022 dollars.
63 Environmental Finance Center at Sacramento State, 2020. Estimating benefits and costs of stormwater management. Part II: Evaluating municipal spending in California. USEPA Region 9 EFC, OWP at Sacramento State, Sacramento, May 2020.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 287 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
In response to a request by the Santa Ana Water Board, the Permittees for the Counties of Orange, Riverside, and San Bernardino submitted the total costs of compliance with TMDLs.

In Orange County, Permittees reported annual costs for fiscal years 2015-16 through 2019- 2064. After adjusting to 2022 dollars, the annual reported cost of compliance with the Sediment TMDL ranged from $166,719.72 to $621,447.73 with an annual average cost of $314,675.85. The Permittees reported the annual cost of compliance with the Nutrients, Fecal Coliform, and Toxics TMDLs ranged from $790,000.21 to $1,465,461.86 with an average annual cost of $1,131,670.37. The cost of compliance with the Coyote Creek metals TMDL ranged from $102,650.38 to $120,952.62 with an average annual cost of $110,374.88.

Table D.7 below summarizes the annual costs of compliance with the TMDLs. The costs have been adjusted to 2022 dollars:

Table D.7: Adjusted Orange County Compliance Costs per TMDL In Riverside County, the costs of compliance with MSAR bacterial TMDL were provided for fiscal years 2016-17 through 2020-2165
. After adjusting to 2022 dollars, the annual cost of
compliance ranged from $525,958.10 to $1,266,295.59 with an annual average cost of $727,679.64.

The annual cost of compliance with the Lake Elsinore/Canyon Lake Nutrients TMDL ranged from $787,632.47 to $3,278,897.51 with an average annual cost of $1,510,874.61. The table below summarizes the annual costs of compliance with the TMDLs. The costs have been adjusted to 2022 dollars:
64 Reported in an email by Orange County on March 25, 2021, and Annual Reports for fiscal years 2015-16 through 2019-20.
65 Annual Reports for fiscal years 2016-17 through 2020-21 TMDL Costs in 2022 Dollars
TMDLs 2015-16 2016-17 2017-18 2018-19 2019-20
Sediment $621,447.73 $246,804.09 $288,856.21 $166,719.72 $249,549.20 Nutrients,
Fecal
Coliform,
Toxics
$790,000.21 $944,261.11 $1,250,530.22 $1,208,096.13 $1,465,461.86 Coyote
Creek
Metals
$108,309.72 $109,795.02 $102,650.38 $110,166.63 $120,952.62

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 288 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Table D.8: Adjusted Riverside County Compliance Costs per TMDL TMDL Costs in 2022 Dollars
TMDLs 2016-17 2017-18 2018-19 2019-20 2020-21
MSAR
Bacterial
TMDL
$582,222.41 $555,244.21 $525,958.10 $708,680.19 $1,266,295.59 LE/CL
Nutrients
TMDL
$1,085,581.13 $787,632.47 $3,278,897.51 $999,636.08 $1,402,627.02 In San Bernardino County, Permittees reported the costs for fiscal years 2016-17 through 2020-2166
. After adjusting to 2022 dollars, the annual cost of compliance with the MSAR bacterial TMDL ranged from $1,441,863.85 to $2,545,488.35 with an annual average cost of $1,985,164.66. The annual cost of compliance with the Big Bear Lake TMDL ranged from $186,409.47 to $261,545.52 with an average annual cost of $213,235.80. The table below summarizes the annual costs of compliance with the TMDLs. 66 Annual Reports for County of Riverside for fiscal years 2016-17 through 2020-21.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 289 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Table D.9: Adjusted San Bernardino County Compliance Costs per TMDL TMDL Costs in 2022 Dollars
TMDLs 2016-17 2017-18 2018-19 2019-20 2020-21
MSAR
Bacterial
TMDL
$1,472,985.02 $1,441,863.85 $1,955,189.40 $2,545,488.35 $2,510,296.69 Big Bear
Lake
TMDL
$261,545.52 $199,787.54 $186,463.54 $186,409.47 $231,971.78 This economic consideration provides a summary of costs associated with the reasonably foreseeable means of compliance with stormwater requirements. This economic consideration combines an array of cost estimates and examples and considers various means of compliance. The costs considered demonstrate the range of costs the Permittee may face in selecting compliance strategies.

The Santa Ana Water Board has provided the Permittees significant flexibility to choose how to implement this Order. This allows the Permittees the opportunity to evaluate and improve their stormwater program while reducing the cost of compliance.

The Santa Ana Water Board finds that the requirements of this Order are reasonably necessary to protect beneficial uses identified in the Basin Plan and the economic information related to costs of compliance supports protecting those beneficial uses.

E. The Need for Developing Housing Within the Region
The population of the Inland Empire is anticipated to grow by 20% over the next 25 years67.

An increase in population creates a higher demand for water, exacerbates usage of natural resources, and increases generation of waste and pollution. To protect human health and the environment, create economic opportunities, and provide attractive and affordable neighborhoods, U.S. EPA encourages smart growth and Low Impact Development (LID)68 (According to U.S. EPA, using smart growth and LID strategies, communities and developers can reduce runoff quantity, protect water quality, and conserve water by developing compactly, preserving ecologically critical open space, and using green infrastructure strategies69
.

The Order contains requirements that support LID practices to protect water quality. LID practices generally increase the local water supply by adding higher quality stormwater runoff to receiving waters and reducing dependence on imported water. High quality water 67https://www.sbsun.com/2023/02/20/inland-empire-to-grow-twice-as-fast-as-rest-of-southern-california-innext-25-years/. Accessed Oct. 17, 2023 68 https://www.epa.gov/smartgrowth/about-smart-growth. Accessed Oct. 17, 2023 69 https://www.epa.gov/smartgrowth/smart-growth-and-water. Accessed Oct. 17, 2023

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 290 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
addresses the water needs associated with increasing housing demand. LID attempts to replicate the natural hydrology of the site, increasing infiltration and reducing pollutant loads in runoff over traditional development, and thereby reduces negative impacts of development on water quality. The LID requirements of the Order emphasize the necessity to balance growth with sustainable water resource management.

The Order also supports an integrated water resources approach that integrates wastewater, non-stormwater, stormwater, recycled water, and potable water planning. This Order includes requirements that support the capture and beneficial use of MS4 discharges on a regional scale. This Order also allows integrated approaches to demonstrate compliance with receiving water limitations and waste load allocations. It encourages collaboration between various dischargers in a watershed to develop compliance solutions.

These dischargers include water suppliers, wastewater treatment plant operators, municipalities, and others with water supply and water quality interests. Collaboration allows the dischargers to integrate water quality challenges with water supply and other community interests and develop solutions that serve multiple purposes. An integrated approach can preserve and augment local groundwater resources thereby reducing imported water needs and increasing local water resiliency. Local water resiliency increases the region’s capacity to support increases in population and the accompanying need for housing.

F. The Need to Develop and Use Recycled Water
Water Code section 13050(n) defines recycled water as “water which, as a result of treatment of waste, is suitable for a direct beneficial use or a controlled use that would not otherwise occur and is therefore considered a valuable resource.” Harvested stormwater does not meet the definition of recycled water since it is not treated.

California’s water supply is anticipated to diminish by up to 10% by 2040 as a result of a hotter, drier climate70
. In anticipation of a reduced water supply, California’s 2022 Water Supply Strategy (the Strategy) calls for increasing recycled water use and stormwater capture to 1.8 million and 0.5 million acre-feet per year, respectively, by 2040.

Increasing recycled water and harvested stormwater are the two main sources of new water supply in the Strategy. Harvested stormwater may, in some cases, reduce demand for recycled water. This may be the case during winter months when the supply of both harvested water and recycled water exceed demand and storage of either is not cost effective. Nevertheless, both recycled water and harvested stormwater provide water supply benefits in alignment with public policy objectives.

The Order supports water supply resilience through LID requirements in section VIII.G.

Section VIII.G includes a hierarchy that requires permittees to consider LID treatment controls, including harvest and use or infiltration measures, prior to other measures which would not provide water supply benefits. The Order further encourages harvest and use by restricting the basis for its rejection. Section VIII.J requires water demand calculations to support rejection of harvest and use on the basis of insufficient water demand under most conditions.
70 California’s Water Supply Strategy – Adapting to a Hotter, Dryer Future. August 2022

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 291 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
As described in section III.A of this Fact Sheet, indirect potable reuse and direct non-potable reuse are major aspects of the Santa Ana Region’s water supply portfolio. In alignment with the Strategy, the Order continues to support recycled water use in the Santa Ana Region by excluding provisions in the previous permits that discouraged regional facilities. In addition, this Order encourages, wherever feasible, retention of stormwater from the 85th percentile, 24-hour storm event, consistent with State Water Board Order WQ 2015-0075. The use of large, regional facilities would potentially serve multiple purposes, including recharge for stormwater, recharge of recycled water, and flood control.

In addition, participation in WMPs provides opportunities for collaboration between entities in constructing regional facilities. As noted above, these facilities may support recycled water in addition to other uses. The Order also incorporates the stormwater retention approach in WMPs to achieve compliance with WQBELs and RWLs. The approach would likely require large, regional infiltration facilities that could support recycled water as well.

Sections XIV.FF and XIV.GG of this Fact Sheet contain further discussion on the stormwater retention approach.

XXII. STATE MANDATES71
Article XIII B, section 6(a) of the California Constitution provides that whenever “any state agency mandates a new program or higher level of service on any local government, the state shall provide a subvention of funds to reimburse that local government for the costs of the program or increased level of service.” No provision of the Order constitutes a reimbursable state mandate under Article XIII B, section (6)(a) of the California Constitution.

A. Permittees Have Authority to Fund Permit Compliance Costs Through Service Charges, Fees, or Assessments.

As a threshold matter, even if any of the Order’s provisions could be considered state mandates, they are not eligible for reimbursement because the Permittees can levy service charges, fees, or assessments sufficient to pay for compliance with the Order. (Gov. Code, § 17556, subd. (d).) Article XIII D, section 6, of the California Constitution, known as Proposition 218, is not an impediment to Permittees’ fee authority.

First, Proposition 218 does not apply to fees or service charges unrelated to real property, such as fees for development permits, other fees imposed on real property development, and fees for inspections incident to permitting. (Cal. Const. Art. XIII D, § 1, subd. (b), § 2, subd. (b), (e), § 3; Department of Finance v. Commission on State Mandates (2022) 85 Cal.App.5th 535, 587 (San Diego MS4 Permit); Department of Finance v. Commission on State Mandates (2021) 59 Cal.App.5th 546, 561-62.) Permittees have authority to recover through regulatory fees their costs of implementing Sections VIII and XIII of the Order, including such “overhead” costs as developing guidance documents, developing construction ordinances, assessing program effectiveness; and related staff training, and recordkeeping and reporting costs found elsewhere in the Order. (See, San Diego MS4 Permit, 85 Cal.App.5th at pp. 551, 581-582, 588-595.)
71 This section includes a brief discussion of mandates law based on statutory and case law as of the date the Order was issued. References to a specific permit provision are not intended to be exhaustive. The omission of any particular provision from this discussion does not suggest that the Santa Ana Water Board believes that provision to constitute a reimbursable state mandate.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 292 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
Second, the voter approval requirements of Proposition 218 do not apply to “fees or charges for sewer, water, and refuse collection services.” (Cal. Const. Art. XIII D, § 6, subd. (c).72
“Water” for purposes of articles XIII C and XIII D, means “water from any source.” (Gov. Code, § 53750, subd. (n).) “Sewer” includes “systems, all real estate, fixtures, and personal property owned, controlled, operated, or managed in connection with or to facilitate sewage collection, treatment, or disposition for sanitary or drainage purposes, including lateral and connecting sewers, interceptors, trunk and outfall lines, sanitary sewage treatment or disposal plants or works, drains, conduits, outlets for surface or storm waters, and any and all other works, property, or structures necessary or convenient for the collection or disposal of sewage, industrial waste, or surface or storm waters.” (Gov. Code, § 53750, subd. (k) (emphasis added); see also, § 53751 (Legislative declarations.) Such fees are subject only to Proposition 218’s majority protest procedures. (Cal. Const. Art. XIII D, §6, subd. (c); Gov. Code, § 53750 et seq.) The majority protest procedure does not eviscerate a local agency’s authority to levy fees for purposes of determining whether compliance costs are reimbursable. (San Diego MS4 Permit, supra, 85 Cal.App.5th at p. 581, citing Paradise Irrigation Dist. v. Commission on State Mandates (2019) 33 Cal.App.5th 174, 192-195.)73
Permittees thus have adequate authority under their police powers to levy service charges, fees or assessments to cover all costs of complying with the Order. (See, Cal.

Const., art. XI, § 7; Freeman v. Contra Costa County Water Dist. (1971) 18 Cal.App.3d 404, 408 (preventing water pollution is a valid exercise of police power).) Permittees likewise have fee authority for “services and facilities furnished … in connection with its … storm drainage …system.” (Health & Safety Code, § 5471, subd. (a).) And they have fee authority for “[a]spects of solid waste handling which are of local concern, including, but not limited to, frequency of collection, means of collection and transportation, level of services, charges and fees, and nature, location, and extent of providing solid waste handling services.” (Pub. Res. Code, § 40059, subd. (a)(1).) B. New or Modified Permit Requirements Do Not Mandate New Programs or Higher Levels of Service.
“Programs” for purposes of Article XIII B, section 6, are: (1) programs that carry out the governmental function of providing services to the public, or (2) laws which, to implement a state policy, impose unique requirements on local governments and do not apply generally to all residents and entities in the state. (San Diego MS4 Permit, supra, at p. 555, citing San Diego Unified School Dist. v. Commission on State Mandates (2004) 33 Cal.4th 859, 874.) The term “higher level of service” refers to “state mandated increases in the services provided by local agencies in existing programs.” (Ibid., internal quotations deleted.) A higher level of service requires “an increase in the actual level or quality of government services provided,” not merely a change that increases the cost of providing services. (San Diego Unified School Dist. at p. 877; County of Los Angeles v. Commission 72 Such authority is also undiminished by Proposition 26, which specifically excludes assessments and property-related fees imposed in accordance with Proposition 218 from the definition of taxes. (Cal.

Const., art. XIII C, § 1, subd. (e)(7).).
73 Permittees had fee authority adequate to fund all requirements related to refuse collection, including associated monitoring and reporting requirements, independent of the amendments to Government Code section 53750. (San Diego MS4 Permit, supra, at pp. 551, 581-582.) This authority would extend to all new requirements implanting the statewide Trash Provisions.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 293 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
on State Mandates (2003) 110 Cal.App.4th 1176, 1191, quoting Workers’ Compensation Mandates Decision, supra, 43 Cal.3d. at p. 55.)
One of the most significant new features of the Order -- the option to comply with various requirements by participating in a watershed management plan (WMP) -- is voluntary, and provides a more flexible, cost-effective way to comply with permit requirements over a longer period of time. The WMP option is therefore not a mandated program. Other requirements of the Order do not constitute a new program or a higher level of service as compared to the requirements contained in the previous permits.

1. Requirements that are also found in other stormwater permits are not unique to local government.

Some of the Order’s requirements are the same as those found in State Water Board Orders WQ 2022-0057-DWQ (NPDES General Permit for Stormwater Discharges Associated with Construction and Land Disturbance Activities) (“CGP”), WQ 2015-0122- DWQ (NPDES General Permit for Storm Water Discharges Associated with Industrial Activities) (“IGP”), and 2022-0033-DWQ (NPDES Statewide Stormwater Permit and Waste Discharge Requirements for State of California Department of Transportation (“Caltrans Permit”). These permits cover, respectively, discharges from public and private construction and industrial sites and CalTrans’ MS4s. These requirements are not unique to local government and are therefore not a “program.”
For example, the Trash Provisions apply to all stormwater dischargers subject to NPDES permitting requirements. (Trash Provisions, §§ IV.A.2 and A.3.c [inland]; Ocean Plan, §§ III.I.6 and L.2.C.) Both the CGP and Caltrans Permit prohibit the discharge of trash and require compliance with statewide Trash Provisions. (CGP, provision IV.B.4; Caltrans Permit, provision 3.3 and Attachment E. The IGP has not been updated since the Trash Provisions were adopted.). In another example, section XIV.B.9 requires that Permittees use effective controls that prevent materials or waste associated with municipal facilities or activities from being dispersed by wind or stormwater runoff. This requirement is based on similar requirements in the CGP. (CGP, Attachments D and E, §§ II.A.2.d. and g., II.A.4.a.)

2. TMDL-based requirements
The TMDL-based requirements in the Order do not require a new program or a higher level of service. MS4 permits issued since 1999 have prohibited discharges that cause or contribute to exceedances of water quality standards in the receiving water, as required by State Water Board Order WQ 99-05. (See, Order No. R8-2002-0010 (Orange County); Order No. R8-2002-0011 (Riverside County); Order No. R8-2002-0012 (San Bernardino County).) TMDL provisions, including federally-required WQBELs, simply provide a process for meeting this requirement, generally based on a compliance schedule that provides Permittees additional time to comply with existing receiving water limitations.

In addition, the federal requirement to comply with TMDL-based WQBELs is not unique to local government. This requirement applies to any stormwater or non-stormwater NPDES permittee assigned a wasteload allocation. (40 CFR §§ 122.44(d)(1)(vii)(B); 130.3(h).)

3. Non-stormwater discharge prohibition

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 294 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
The CWA has long required that all dischargers, including private industrial dischargers and local governments, effectively prohibit “all types” of non-stormwater discharges identified as sources of pollutants to waters of the United States. (33 U.S.C. § 1342(p)(3)(B)(ii); 40 C.F.R. § 122.26(d)(2)(iv)(B)(1).) In addition, MS4 dischargers must demonstrate adequate legal authority, through ordinance, permit, or other means, to prohibit illicit discharges from others to the MS4. (40 C.F.R. § 122.26(d)(2)(i)(B).) As a result, the Permittees have been subject to these requirements since 1990. (Order Nos. 90-01 (Orange County), 90-104 (Riverside County), and 90-136 (San Bernardino County).)
The requirements associated with effectively prohibiting non-stormwater discharges do not change or increase the level or quality of service already required by law; they simply require the Permittees to comply with existing federal law to prohibit non-stormwater discharges to waters of the United States.

Finally, non-municipal dischargers of stormwater are also subject to the non-stormwater prohibition. (CGP, provisions IV.A (authorized non-stormwater discharges), IV.B.3. (nonstormwater prohibition), IV.B.4 (trash prohibition); IGP, provisions III.B (non-stormwater prohibitions), IV.A (authorized non-stormwater discharges); Caltrans Permit, provisions

3.9 (non-stormwater prohibition) and 3.3, and Attachment E (trash prohibition).) These permits cover, respectively, discharges from public and private construction and industrial sites and CalTrans’ MS4s. Thus, the non-stormwater prohibition is not unique to local government and is not a “program.”

4. Discretionary projects
Building standards that are not unique to local governments do not meet the definition of a “program.” In addition, requirements for stormwater controls on municipal development or redevelopment projects are not mandates because Permittees are under no legal or practical compulsion to construct or operate such facilities, but rather do so at their own discretion. (See, Coast Community College Dist. v. Commission on State Mandates (2022) 13 Cal.5th 800 [defining “legal compulsion” and “practical compulsion”].) Any costs Permittees incur to comply with LID, hydromodification, or retrofitting requirements applicable to such facilities do not constitute state mandates.

C. The Permit Requirements Are Non-Reimbursable Federal Mandates.

Even if some of the Order’s requirements could be considered a new program or higher level of service, those requirements are required to meet the standards set forth in the federal Clean Water Act and implementing regulations and are therefore non-reimbursable federal mandates.74
If a requirement is mandated by a federal law or regulation and the federal requirements result in increased costs, no reimbursement is required unless a state statute or executive order mandates costs that exceed the federal mandate. (Gov. Code, § 17556, subd. (c).) The Order implements federally mandated requirements under the CWA and implementing regulations, which are not subject to reimbursement. This includes federal requirements to: (i) effectively prohibit non-stormwater discharges through the MS4 to 74 Other sections of this Fact Sheet provide additional citations to federal requirements mandating specific provisions.

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 295 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
receiving waters; (ii) reduce the discharge of pollutants in stormwater to the maximum extent practicable; (iii) include such other provisions as the Santa Ana Water Board determines appropriate for the control of such pollutants; (iv) attain applicable TMDL waste load allocations; and (v) conduct monitoring and reporting.

Non-stormwater discharge prohibition: Federal law requires that an MS4 permit effectively prohibit non-stormwater discharges through the MS4 to receiving waters. (33 U.S.C. § 1342(p)(3)(B)(ii).) Regulatory exceptions for certain categories of low-threat discharges do not apply to discharges that are identified as a significant source of pollutants to waters of the United States. (40 C.F.R. § 122.26(d)(2)(IV)(B).) The Order includes various requirements to achieve the effective prohibition of non-stormwater discharges, including Sections IV (Discharge Prohibitions), IX (Illicit Discharge Detection and Elimination Program), and various education, outreach and training requirements. These requirements are compelled by federal law and are separate from the requirement to reduce the discharge of pollutants to the maximum extent practicable.

TMDL requirements: The CWA requires TMDLs be established for waterbodies that do not meet federal water quality standards. (33 U.S.C. § 1313(d).) The CWA also requires that MS4 permits include “such other provisions as the Administrator or the State determines appropriate for the control of [] pollutants.” (33 U.S.C. § 1342(p)(3)(B)(iii).) USEPA interprets this provision to mandate “controls to reduce the discharge of pollutants to the maximum extent practicable, and where necessary water quality-based controls.” (Phase I Stormwater Regulations, Final Rule, 55 Fed. Reg. 47990, 47994 (Nov. 16, 1990) [emphasis added]; see also Building Industry Ass’n of San Diego County v. State Water Resources Control Bd. (2004) 124 Cal.App.4th 866, 882-887; Phase II Stormwater Regulations, Final Rule, 64 Fed. Reg. 68722, 68737.)
Once USEPA or a state establishes a TMDL, federal law requires that NPDES permits must contain water quality-based effluent limitations (WQBELs) consistent with the assumptions and requirements of any applicable waste load allocation (WLA). (40 C.F.R. § 122.44(d)(1)(vii)(B).) Indeed, TMDLs are developed for the purpose of specifying requirements for the achievement of water quality standards in impaired waters. (33 U.S.C. § 1313(d); 40 C.F.R. § 130.7.) Associated compliance schedules must require NPDES permittees to attain WLAs as soon as possible. (40 C.F.R. § 122.47.) The Order’s requirements for attainment of TMDL WLAs are therefore compelled by federal law.

Monitoring and reporting requirements: Federal law requires that NPDES permits incorporate monitoring and reporting provisions. (33 U.S.C. §§ 1318(a), 1342(a)(2); 40 C.F.R. §§ 122.26(d)(2)(i)(F); 122.41(h), (j)-(l); 122.42(c); 122.44(i); 122.47(a)(4); 122.48.) Monitoring and reporting must be adequate to determine compliance and noncompliance with permit conditions and to report that information to permitting authorities. (Ibid.) None of the current permits explicitly require monitoring to determine compliance with receiving water limitations or with wasteload allocations that were expressed as WQBELs. In many cases, monitoring activities were controlled by other resolutions or orders adopted by the Santa Ana Water Board. In some cases, monitoring activities were changed without corresponding updates to the permits’ monitoring programs. The Order includes updated monitoring and reporting requirements to address these deficiencies. The Order’s monitoring and reporting requirements are thus imposed pursuant to federal law.

Maximum Extent Practicable (MEP) standard: The CWA mandates that the Order “require controls to reduce the discharge of pollutants to the maximum extent practicable.” (33

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 296 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
U.S.C. § 1342(p)(3)(B)(iii).) Department of Finance v. Commission on State Mandates (2016) 1 Cal.5th 749, as modified on denial of rehearing (Nov. 16, 2016) (Los Angeles MS4 Permit) analyzed whether the CWA’s MEP standard required four provisions concerning trash receptacles and inspections in the 2001 Los Angeles County MS4 permit. In concluding that the provisions were not required by federal law, the Supreme Court stated that, “[h]ad the Regional Board found when imposing the disputed permit conditions, that those conditions were the only means by which the maximum extent practicable standard could be implemented, deference to the board’s expertise in reaching that finding would be appropriate.” (Los Angeles MS4 Permit, supra, 1 Cal.5th at p. 768.) The Supreme Court further stated that “[s]uch findings are “case specific, based among other things on factual circumstances.” (Id., fn. 15.) To be entitled to deference, regional water boards must make an express finding that the particular set of permit conditions finally embodied in a given permit is required to meet that federal standard and must support that finding with evidence.

The Santa Ana Water Board finds that the Order specifies requirements necessary for the Permittees to reduce the discharge of pollutants in MS4 discharges to the MEP. The Order establishes requirements for stormwater management “minimum control measures,”75 including programs for public information and participation, industrial and commercial facilities, construction activities, planning and land development, public agency activities, and illicit discharge detection and elimination, among others required by 40 CFR section 122.26(d)(2)(iv). The requirements of these programs represent structural and nonstructural water quality control measures that are effective, technically feasible, and generally accepted as appropriate.

Past approaches to the iterative process of achieving MEP have not resulted in the stormwater quality improvements necessary to meet the MEP standard and meet water quality standards. The Order therefore requires program effectiveness assessments (PEAs). New restrictions on the use of USEPA’s Green Streets program are necessary because this guidance contains few enforceable standards for selecting structural treatment controls for priority projects that involved improvements to existing transportation rights of way. These rights of way make up 10% to 25% of an urban area and are a significant source of pollutants. Audits and inspections by Santa Ana Water Board staff have shown that use of the guidance has resulted in excluding structural treatment controls with no meaningful analysis, in conflict with the federal requirement to reduce the discharge of pollutants to the MEP.

At the same time, existing requirements that are no longer necessary have been eliminated or reduced. Examples include reduced frequency of refresher training, reducing reporting frequency for non-compliant industrial or construction sites, reduced inspection frequency for high priority sites, elimination of inspection requirements for shortduration construction projects, a new provision authorizing the Executive Officer to waive requirements for discharges that may create hydrologic conditions of concern (Section 75 The term “minimum control measures” is borrowed from USEPA’s Storm Water Phase II Final Rule.

It is not found in 40 CFR section 122.26(d)(2). The control measures the term refers to in the Phase II Final Rule are essentially the same as those in 40 CFR section 122.26(d)(2). The term is used here as a convenient way to collectively describe the control measures in 40 CFR section 122.26(d)(2).

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 297 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
VIII.L.1.e) and a more streamlined process for obtaining waivers of treatment controls for priority projects subject to WQMPs (section VIII.E).

Section XII of the Order establishes an elective program providing an alternative compliance path through the preparation of a Watershed Management Plan (WMP).

WMPs allow the Permittees to identify water quality issues and propose the specific control measures to achieve the receiving water limitations and numeric WQBELs in accordance with time schedules that meet federal requirements. This alternative provides Permittees with flexibility to select the most cost-effective water quality control measures that will reduce pollutants in stormwater to the maximum extent practicable, comply with TMDL wasteload allocations, and meet other receiving water limitations.

Finally, USEPA’s inclusion of equivalent or substantially similar provisions in its MS4 permits support a finding that the provisions are necessary to achieve MEP. The Santa Ana Water Board has examined the following USEPA issued permits, among others, and concluded that they contain equivalent and/or substantially similar provisions:

Massachusetts MS4 General Permit, Washington D.C. MS4 Permit, Middle Rio Grande (Albuquerque, NM) MS4 Watershed Permit, Boise/Garden City MS4 Permit, and Guam MS4 Permit.

The Santa Ana Water Board finds that the programmatic requirements of the Order are necessary to meet the MEP standard. The mix of pollution controls and best management practices are necessary to attain the level of pollutant reduction expected by the demanding federal MEP standard, but also balances different interests such as effectiveness, regulatory compliance, public acceptance, cost, and technical feasibility. To the extent there may be multiple means of achieving pollutant reductions and that there could be trade-offs between program areas with potentially higher costs and greater pollutant reductions, the Order affords Permittees discretion to select the specific means of reducing the discharge of pollutants to the MEP based on the methodical application of performance metrics. This finding is the expert conclusion of the Santa Ana Water Board based on its technical expertise and experience administering the MS4 program.

XXIII. PUBLIC PARTICPATION AND NOTIFICATION
The Santa Ana Water Board has considered the issuance of WDRs that will serve as an NPDES permit for MS4 discharges within the Santa Ana Region. The Santa Ana Water Board staff has encouraged public participation in the permit development process. Over a period of many years, the Santa Ana Water Board has held multiple listening sessions, workshops, and Board meeting agenda items focusing on issues pertinent to stakeholders and Permittees in all three counties. Additionally, Santa Ana Water Board staff have met with Permittees and interested stakeholders upon request. The following information is provided pursuant to 40 CFR section 124.8(b)(6) and (7).

A. Overview of Regional MS4 Permit Outreach Efforts
Santa Ana Water Board staff began discussions regarding a regional MS4 permit concept with the San Bernardino and Riverside Counties on January 30, 2014. There were further meetings with the counties on March 5, 2015, June 23, 2015, and August 16, 2016.

Santa Ana Water Board staff held a series of meetings on August 21, 2018, August 28, 2018, September 18, 2018, September 19, 2018, and October 9, 2018 with

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 298 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
representatives of Riverside County, Orange County, San Bernardino County, and NGOs to discuss combining all existing MS4 permits into a single, regionwide permit. Another set of individual meetings were held on November 27, 2018, November 28, 2018, and December 5, 2018 with Riverside County, Orange County, and San Bernardino County MS4 permittees, respectively.

On June 16, 2021, August 1, 2022, and May 3, 2023, Santa Ana Water Board staff also met with USEPA to discuss the regional MS4 permit.

On January 25, 2022, Santa Ana Water Board staff released a staff working proposal for a regional, Phase I MS4 permit (referred to as the “Staff Working Proposal”) to solicit input from all stakeholders such as Permittees, non-governmental agencies, and other interested parties. Santa Ana Water Board staff have incorporated several revisions based on the prior inputs and informal discussions.

At the request of the Permittees, a series of facilitated remote meetings were held to hear the comments by the Permittees which included Permittees from the Counties of Riverside, Orange, and San Bernardino, referred to as the Tri-County Group (TCG). On January 12, 2022, a kickoff meeting was held between Santa Ana Water Board staff and the TCG. Further meetings were held on January 26, 2022, March 22, 2022, April 5, 2022, April 26, 2022, June 14, 2022, August 2, 2022, January 17, 2023, February 8, 2023, June 16, 2023, and July 12, 2023. Separate TMDL focused meetings were held on March 6, 2023 for Riverside County and San Bernardino County, and on March 13, 2023 for Orange County.

Separate meetings took place between Santa Ana Water Board staff and the Orange County Coastkeeper on March 1, 2023, April 13, 2023, and May 22, 2023.

Santa Ana Water Board staff also held public workshops to solicit input from all interested parties. The first workshop was held on February 4, 2022, to inform the Santa Ana Region’s Board members of the Staff Working Proposal and hear comments from the public. Other workshops and listening sessions were held on August 2, 2022, May 10, 2023, May 16, 2023, May 17, 2023, and May 18, 2023.

Following issuance of a draft Order on March 5, 2024 and during the 60-day written public comment period, the Santa Ana Water Board held a public workshop on XXXX X, 2024 to solicit additional input from all interested parties.

B. Outreach and AB 2108
Effective January 1, 2023, Assembly Bill (AB) 2108 added sections 189.7 and 13149.2 to the California Water Code. Water Code section 189.7 requires the Water Boards to conduct equitable, culturally relevant outreach when considering proposed discharges of waste that may have disproportionate impacts on water quality in disadvantaged communities or tribal communities. Water Code section 13149.2(c) requires that when the Water Boards issue or re-issue regional or statewide WDRs, they make a concise, programmatic finding on potential environmental justice, tribal impact, and racial equity considerations related to the issuance, particularly on any anticipated water quality impacts to those communities and measures available to address them. For reissuances, the finding may be limited to considerations related to any changes to the requirements of

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 299 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
the prior WDRs. The finding is based on readily available information identified by staff or raised during the public review process.

The discharge of stormwater and non-stormwater runoff from Municipal Separate Storm Sewer Systems (MS4s) in the Santa Ana Region regulated by this Order may occur in the area of one or more disadvantaged or tribal communities. The scope of the discharges encompasses the entirety of the Santa Ana Region and therefore implicates numerous disadvantaged and tribal communities. After consulting the Native American Heritage Commission, Santa Ana Water Board staff identified 22 different tribal communities within the Santa Ana Region. Further, a search of CalEnviroScreen 4.0 identified potentially 200 different disadvantaged communities across portions of Orange, Riverside and San Bernardino Counties with the Santa Ana Region.

1. Targeted AB 2108 Outreach
Consistent with Water Code section 189.7, the Santa Ana Water Board has conducted outreach to potentially affected disadvantaged and/or tribal communities concerning this Order. The Santa Ana Water Board’s efforts to do so following the effective date of AB 2108 in 2023 are summarized below.

In early 2023, Water Board staff used CalEnviroScreen 4.0 to select locations for a series of public workshops intended to solicit comments from disadvantaged communities. These workshops were held on May 10, 2023 in the City of San Bernardino, May 17, 2023 in the City of Moreno Valley, and May 18, 2023 in the City of Huntington Beach. In addition, a virtual, online public workshop was held on May 16, 2023.

On May 11, 2023, Santa Ana Water Board staff sent 22 letters to tribal contacts within the Santa Ana Region provided by the Native American Heritage Commission. The letter invited recipients to participate in the development of the Order through a variety of means, including by attending workshops and providing feedback on the permit.

Santa Ana Water Board staff received no responses to these letters requesting to engage on the permit.

On September 23, 2023, Santa Ana Water Board staff participated in the 2023 Riverside Community Climate Action Day event and had a booth to facilitate public outreach and interaction. At the event, staff distributed flyers that encouraged the public to provide feedback on the Order and attend future workshops.

Additionally, Santa Ana Water Board staff distributed and posted flyers at key locations within disadvantaged communities. These locations include libraries, laundromats, coffee shops, churches, mosques, and synagogues. The flyers defined key technical terms related to MS4s, described the Permit, and encouraged the public to provide feedback and attend future workshops. As of October 2023, around 20 flyers were posted in Orange County and 70 in Riverside and San Bernardino Counties combined.

2. Environmental Justice Findings
Pursuant to Water Code section 13149.2, the Santa Ana Water Board has taken into account environmental justice, tribal impact, and racial equity considerations in issuing

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 300 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
this Order. As noted above, discharges regulated by this Order may occur in the area of one or more disadvantaged communities or tribal communities.

Discharges of stormwater and non-stormwater runoff through MS4s within the Santa Ana Region convey pollutants to surface waters. Polluted stormwater and nonstormwater discharges from MS4s are a leading cause of water quality impairment in the Santa Ana Region. These discharges are often contaminated with pesticides, fertilizers, fecal indicator bacteria and associated pathogens, trash, oil and other automotive byproducts, and many other toxic substances generated by activities in the urban environment. Water that flows over streets, parking lots, construction sites, and industrial, commercial, residential, and municipal areas convey these pollutants through the MS4 directly into receiving waterbodies of the Santa Ana Region.

This Order addresses potential adverse impacts from MS4 discharges through numerous different means, including but not limited to by:
· Prohibiting all non-stormwater discharges, with a few enumerated exceptions, through the MS4 to all receiving waters;
· Requiring that Permittees comply with the “maximum extent practicable” technology-based standard set forth in CWA section 402(p)(3)(B)(iii) and implement the minimum control measures required of a stormwater management program by 40 CFR section 122.26(d)(2)(iv);
· Requiring compliance with receiving water limitations and applicable WQBELs based on TMDL WLAs established for waters in the Santa Ana Region, as required by CWA section 402(p)(3)(B)(iii) and 40 CFR section 122.44(d)(1)(vii)(B); · Encouraging, wherever feasible, retention of stormwater from the 85th percentile, 24-hour storm event, consistent with State Water Board Order WQ 2015-0075; · Allowing voluntary participation in WMPs as an alternative for Permittees that gives them the flexibility to implement the requirements of this Order on a watershed scale through customized strategies, control measures, and BMPs, while still providing reasonable assurance that the Permittees’ MS4 discharges achieve WQBELs by applicable compliance deadlines and do not cause or contribute to exceedances of receiving water limitations;
· Requiring an extensive monitoring and reporting program designed to identify changes in water quality at representative outfalls and in receiving waters; · Requiring that Permittees engage in the “iterative process” by continual improvement and modification of strategies, control measures, and BMPs as necessary based on analysis of monitoring data collected pursuant to the MRP to ensure that applicable WQBELs and receiving water limitations and other milestones set forth in the WMP will be achieved.

The Order is a reissuance of prior MS4 permits issued in three different counties – Orange (Order No. R8-2009-0030 as amended by No. R8-2010-0062), Riverside (Order No. R8-2010-0033), and San Bernardino (Order No. R8-2010-0036). The Order generally includes either similar or more stringent provisions than in the prior permits, and therefore changes to the requirements are not expected to result in any new water quality impacts on disadvantaged or tribal communities.

The addition of WMPs as an alternative means of compliance with WQBELs and receiving water limitations is a new addition to the Order. Whereas the past permits

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 301 of 320 Fact Sheet
Santa Ana Regional MS4 Permit
provided BMP-based WQBELs for those TMDLs whose compliance deadlines had not passed, the Order defaults to the inclusion of numeric WQBELs based on the TMDL WLAs. This is a more stringent approach than in past permits. However, the Permittees may, alternatively and voluntarily, comply with the numeric WQBELs by implementing approved WMPs comprised of a suite of BMP-based control measures.

WMPs must be accompanied by demonstrations, via the reasonable assurance analysis (RAA), that the BMPs will meet the numeric WQBELs and receiving water limitations.

Although the WMPs essentially allow compliance schedules for achievement of WQBELs, the final compliance deadline must be as short as possible and must not exceed the final deadline for attainment of the TMDL WLA for that pollutant-waterbody combination found in the Basin Plan. The Order mitigates any potential impacts to disadvantaged and/or tribal communities that may arise from WMPs by requiring that WMPs include public comment and participation prior to approval.

C. Written Comment Period and Public Hearing
The Santa Ana Water Board notified the Permittees and interested agencies and persons of its intent to prescribe WDRs for Phase I MS4 discharges within the Santa Ana Region and has provided an opportunity to submit written comments and recommendations. A Notice of Public Hearing was disseminated to interested persons and posted on the Santa Ana Water Board’s website. The public had access to the agenda and any changes in dates and locations through the Santa Ana Water Board’s website at:
http://www.waterboards.ca.gov/santaana.

Interested persons were invited to submit written comments concerning the draft WDRs during a 60-day comment period. Comments were due either in person or by mail to the Executive Officer at the Santa Ana Water Board at the address on the cover page of this Order, by fax to (951) 320-6362, or by email to
[email protected]. The deadline to submit written comments was by 5:00 pm on DATE, 2024.

The Santa Ana Water Board held a public hearing on the tentative Order during its regular Board meeting on the following date and time and at the following location:

Date: [DATE, 2024]
Time: 9:00 a.m. each day
Location: [ADD]
Parties and interested persons were invited to attend. At the public hearing, the Santa Ana Water Board heard and considered testimony pertinent to the discharge and WDRs.

23.C

Santa Ana Regional MS4 Permit
Appendix E
Acronyms

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 303 of 320 Attachment E
Santa Ana Regional MS4 Permit
Attachment E

ACRONYMS
APN – Assessor's parcel number
ASBS – Area of Special Biological Significance
BMP – Best Management Practice
CCR – California Code of Regulations (State Water Board regulations are in Title 23) CERCLA – Comprehensive Environmental Response, Compensation, and Liability Act CEQA – California Environmental Quality Act (section 21000 et seq. of the California Public Resources Code).

CFR – Code of Federal Regulations
CFU – Colony Forming Units
CMP – Consolidated Program for Water Quality Monitoring, Riverside County Flood Control and Water Conservation District, October 2008.

CBRP – Comprehensive Bacteria Reduction Plan
CNRP – Comprehensive Nutrient Reduction Plan
CGP – Construction General Permit
CTR – California Toxics Rule
CWA – Federal Clean Water Act
CWC – California Water Code
CZARA – Coastal Zone Act Reauthorization Amendments
DAMP – Drainage Area Management Plan
DDT – Dichlorodiphenyltrichloroethane
DAR – Duly Authorized Representative
ESAs – Environmentally Sensitive Areas
EO – Executive Officer

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 304 of 320 Attachment E
Santa Ana Regional MS4 Permit
GIS – Geographical Information System.

HCOC – Hydrologic Condition of Concern
IC/ID – Illicit Connections/Illegal Discharges
IDDE – Illicit Discharge Detection and Elimination
IGP – Industrial General Permit
ISWEBE – Inland Surface Waters, Enclosed Bays, and Estuaries of California LA – Load Allocation
LID – Low Impact Development
LRP – Legally Responsible Person
MEP – Maximum Extent Practicable
MPN – Most Probable Number
MOU – Memorandum of Understanding
MRP – Monitoring and Reporting Program
MSAR – Middle Santa Ana River
MS4 – Municipal Separate Storm Sewer System
NPDES – National Pollutant Discharge Elimination System NGOs – Non-governmental Organizations
NOI – Notice of Intent
NTR – National Toxics Rule
POTW – Publicly Owned Treatment Works
QAPP – Quality Assurance Project Plan
RCFC&WCD – Riverside County Flood Control and Water Conservation District REC – Recreational Beneficial Use.

ROWD – Report of Waste Discharge

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 305 of 320 Attachment E
Santa Ana Regional MS4 Permit
SAR – Santa Ana Region
SARA – Superfund Amendments and Reauthorization Act
SBCFCD – San Bernardino County Flood Control District
SCCWRP – Southern California Coastal Water Research Project SIC – Standard Industrial Classification
SIP – State Implementation Policy
SMP – Scrap Metal Permit
SSO – Sanitary Sewer Overflow
SWAMP – Surface Water Ambient Monitoring Program
SWPPP – Stormwater Pollution Prevention Plan
TMDL – Total Maximum Daily Load
USEPA – United States Environmental Protection Agency
WDID – Waste Discharge Identification
WDRs – Waste Discharge Requirements
WLAs – Waste Load Allocations
WMP – Watershed Management Plan
WQBELs – Water Quality-Based Effluent Limitations
WQMP – Water Quality Management Plan

23.C

Santa Ana Regional MS4 Permit
Attachment F
Standard Provisions

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 307 of 320 Attachment F
Santa Ana Regional MS4 Permit

ATTACHMENT F

STANDARD PROVISIONS
I. STANDARD PROVISIONS – PERMIT COMPLIANCE
A. Duty to Comply

1. Permittees must comply with all the terms, requirements, and conditions of this Order. Any noncompliance constitutes a violation of the Clean Water Act (CWA) and the California Water Code and is grounds for enforcement action; permit termination, revocation and reissuance, or modification; denial of a permit renewal application; or a combination thereof. (40 CFR § 122.41(a); Wat. Code, §§ 13261, 13263, 13265, 13268, 13000, 13001, 13304, 13350, 13385)

2. Permittees shall comply with effluent standards or prohibitions established under section 307(a) of the CWA for toxic pollutants within the time provided in the regulations that establish these standards or prohibitions, even if this Order has not yet been modified to incorporate the requirement. (40 CFR § 122.41(a)(1))

3. Permittees shall comply with the provisions herein outlined in Attachment F of this Order. If there is any conflict, duplication, or overlap between provisions specified in this Order, the more stringent provision shall apply.

B. Need to Halt or Reduce Activity Not a Defense
It shall not be a defense for a Permittee, in an enforcement action, that it would have been necessary to halt or reduce the permitted activity to maintain compliance with the conditions of this Order. (40 CFR § 122.41(c)) C. Duty to Mitigate
Permittees shall take all reasonable steps to minimize or prevent any discharge in violation of this Order that has a reasonable likelihood of adversely affecting human health or the environment. (40 CFR § 122.41(d))
D. Proper Operation and Maintenance
Permittees shall, at all times, properly operate and maintain all facilities and systems of treatment and control (and related appurtenances) which are installed or used by the Permittee to achieve compliance with the conditions of this Order. Proper operation and maintenance also includes adequate

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 308 of 320 Attachment F
Santa Ana Regional MS4 Permit
laboratory controls and appropriate quality assurance procedures. This provision requires the operation of backup or auxiliary facilities or similar systems that are installed by a Permittee only when necessary to achieve compliance with the conditions of this Order. (40 CFR § 122.41(e)) E. Property Rights

1. This Order does not convey any property rights of any kind or any exclusive privileges. (40 CFR § 122.41(g))

2. The issuance of this Order does not authorize any injury to persons or property or invasion of other private rights, or any infringement of state or local law or regulations. (40 CFR § 122.5(c))
F. Inspection and Entry
Permittees shall allow the Santa Ana Water Board, State Water Board, USEPA, and/or their authorized representatives (including an authorized contractor acting as their representative), upon the presentation of credentials and other documents, as may be required by law, to (33 USC § 1318(a)(4)(B); 40 CFR § 122.41(i); Wat. Code, §§ 13267, 13383):

1. Enter upon the Permittee's premises where a regulated facility or activity is located or conducted, or where records are kept under the conditions of this Order (33 USC § 1318(a)(4)(B)(i); 40 CFR § 122.41(i)(1); Wat. Code, §§ 13267, 13383);

2. Have access to and copy, at reasonable times, any records that must be kept under the conditions of this Order (33 USC § 1318(a)(4)(B)(ii); 40 CFR § 122.41(i)(2); Wat. Code, §§ 13267, 13383);

3. Inspect and photograph, at reasonable times, any facilities, equipment (including monitoring and control equipment), practices, or operations regulated or required under this Order (33 U.S.C. § 1318(a)(4)(B)(ii); 40 CFR § 122.41(i)(3); Wat. Code, §§ 13267, 13383); and

4. Sample or monitor, at reasonable times, for the purposes of assuring Order compliance or as otherwise authorized by the CWA or the Water Code, any substances, or parameters at any location. (33 USC § 1318(a)(4)(B); 40 CFR § 122.41(i)(4); Wat. Code, §§ 13267, 13383)
G. Bypass

1. Definitions

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 309 of 320 Attachment F
Santa Ana Regional MS4 Permit
a. “Bypass” means the intentional diversion of waste streams from any portion of a treatment facility. (40 CFR § 122.41(m)(1)(i)) b. “Severe property damage” means substantial physical damage to property, damage to the treatment facilities, which causes them to become inoperable, or substantial and permanent loss of natural resources that can reasonably be expected to occur in the absence of a bypass. Severe property damage does not mean economic loss caused by delays in production. (40 CFR § 122.41(m)(1)(ii))

2. Bypass not exceeding limitations. Permittees may allow any bypass to occur which does not cause exceedances of effluent limitations, but only if it is for essential maintenance to assure efficient operation. These bypasses are not subject to the provisions listed in Standard Provisions – Permit Compliance Parts I.G.3, I.G.4, and I.G.5 of this Attachment F. (40 CFR § 122.41(m)(2))

3. Prohibition of bypass. Bypass is prohibited, and the Santa Ana Water Board may take enforcement action against a Permittee for bypass, unless (40 CFR § 122.41(m)(4)(i)):
a. Bypass was unavoidable to prevent loss of life, personal injury, or severe property damage (40 CFR § 122.41(m)(4)(i)(A));
b. There were no feasible alternatives to the bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, or maintenance during normal periods of equipment downtime. This condition is not satisfied if adequate back-up equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass that occurred during normal periods of equipment downtime or preventive maintenance (40 CFR § 122.41(m)(4)(i)(B)); and
c. The Permittee submitted notice to the Santa Ana Water Board as required under Standard Provisions – Permit Compliance Part I.G.5 of this Attachment F. (40 CFR § 122.41(m)(4)(i)(C))

4. The Santa Ana Water Board may approve an anticipated bypass, after considering its adverse effects, if the Santa Ana Water Board determines that it will meet the three conditions listed in Standard Provisions – Permit Compliance Part I.G.3 above. (40 CFR § 122.41(m)(4)(ii))

5. Notice

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 310 of 320 Attachment F
Santa Ana Regional MS4 Permit
a. Anticipated bypass. If the Permittee knows in advance of the need for a bypass, it shall submit prior notice, if possible, at least 10 days before the date of the bypass. The notice shall be sent to the Santa Ana Water Board. As of December 21, 2020, all notices must be submitted electronically to the initial recipient defined in Standard Provisions – Reporting Part V.J of this Attachment F. Notices shall comply with 40 CFR part 3, 40 CFR section 122.22, and 40 CFR part 127. (40 CFR § 122.41(m)(3)(i))
b. Unanticipated bypass. Permittees shall submit notice of an unanticipated bypass as required in Standard Provisions - Reporting Part V.E of this Attachment F (24-hour notice). The notice shall be sent to the Santa Ana Water Board. As of December 21, 2020, all notices must be submitted electronically to the initial recipient defined in Standard Provisions – Reporting Part V.J of this Attachment F. Notices shall comply with 40 CFR part 3, 40 CFR section 122.22, and 40 CFR part 127. (40 CFR § 122.41(m)(3)(ii))
H. Upset
Upset means an exceptional incident in which there is unintentional and temporary noncompliance with technology-based permit effluent limitations because of factors beyond the reasonable control of the Permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation. (40 CFR § 122.41(n)(1))

1. Effect of an upset. An upset constitutes an affirmative defense to an action brought for noncompliance with such technology-based permit effluent limitations if the requirements of Standard Provisions – Permit Compliance Part I.H.2 below are met. No determination made during administrative review of claims that noncompliance was caused by upset, and before an action for noncompliance, is final administrative action subject to judicial review. (40 CFR § 122.41(n)(2))

2. Conditions necessary for a demonstration of upset. A Permittee who wishes to establish the affirmative defense of upset shall demonstrate, through properly signed, contemporaneous operating logs or other relevant evidence that (40 CFR § 122.41(n)(3)):
a. An upset occurred and that the Permittee can identify the cause(s) of the upset (40 CFR § 122.41(n)(3)(i));

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 311 of 320 Attachment F
Santa Ana Regional MS4 Permit
b. The permitted facility was, at the time, being properly operated (40 CFR § 122.41(n)(3)(ii));
c. The Permittee submitted notice of the upset as required in Standard Provisions – Reporting V.E.2.b below (24-hour notice) (40 CFR § 122.41(n)(3)(iii)); and
d. The Permittee complied with any remedial measures required under Standard Provisions – Permit Compliance I.C above. (40 CFR § 122.41(n)(3)(iv))

3. Burden of proof. In any enforcement proceeding, the Permittee seeking to establish the occurrence of an upset has the burden of proof. (40 CFR § 122.41(n)(4))
II. STANDARD PROVISIONS – PERMIT ACTION
A. General
This Order may be modified, revoked, reissued, or terminated for cause. The filing of a request by the Permittee for modification, revocation and reissuance, or termination, or a notification of planned changes or anticipated noncompliance does not stay any Order condition. (40 CFR § 122.41(f)) B. Duty to Reapply
If a Permittee wishes to continue an activity regulated by this Order after the expiration date of this Order, the Permittee must apply for and obtain a new permit. (40 CFR § 122.41(b))
C. Transfers
This Order is not transferable to any person except after notice to the Santa Ana Water Board. The Santa Ana Water Board may require modification or revocation and reissuance of the Order to change the name of the Permittee and incorporate such other requirements as may be necessary under the CWA and the Water Code. (40 CFR §§ 122.41(l)(3), 122.61)
III. STANDARD PROVISIONS – MONITORING
A. Samples and measurements taken for the purpose of monitoring shall be representative of the monitored activity. (40 CFR § 122.41(j)(1)) B. Monitoring must be conducted according to test procedures approved under 40 CFR part 136 for the analyses of pollutants unless another method is required

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 312 of 320 Attachment F
Santa Ana Regional MS4 Permit
under 40 CFR chapter 1, subchapter N. Monitoring must be conducted according to sufficiently sensitive test methods approved under 40 CFR part 136 for the analysis of pollutants or pollutant parameters or as required under 40 CFR chapter 1, subchapter N. For the purposes of this paragraph, a method is sufficiently sensitive when:

1. The method minimum level (ML) is at or below the level of the most stringent effluent limitation established in the permit for the measured pollutant or pollutant parameter, and either the method ML is at or below the level of the most stringent applicable water quality criterion for the measured pollutant or pollutant parameter or the method ML is above the applicable water quality criterion but the amount of the pollutant or pollutant parameter in the facility’s discharge is high enough that the method detects and quantifies the level of the pollutant or pollutant parameter in the discharge; or

2. The method has the lowest ML of the analytical methods approved under 40 CFR part 136 or required under 40 CFR chapter 1, subchapter N for the measured pollutant or pollutant parameter.

In the case of pollutants or pollutant parameters for which there are no approved methods under 40 CFR part 136 or otherwise required under 40 CFR chapter 1, subchapter N, monitoring must be conducted according to procedure specified in this Order and/or the MRP for such pollutants or pollutant parameters. (40 CFR §§ 122.21(e)(3), 122.41(j)(4), 122.44(i)(1)(iv)) IV. STANDARD PROVISIONS – RECORDS
A. Permittees shall retain records of all monitoring information, including all calibration and maintenance records and all original strip chart recordings for continuous monitoring instrumentation, copies of all reports required by this Order, and records of all data used to complete the application for this Order, for a period of at least three (3) years from the date of the sample, measurement, report or application. This period may be extended by request of the Santa Ana Water Board Executive Officer or USEPA at any time. (40 CFR § 122.41(j)(2); Wat. Code § 13383(a)).

B. Records of monitoring information shall include:

1. The date, exact place, and time of sampling or measurements (40 CFR § 122.41(j)(3)(i));

2. The individual(s) who performed the sampling or measurements (40 CFR § 122.41(j)(3)(ii));

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 313 of 320 Attachment F
Santa Ana Regional MS4 Permit

3. The date(s) analyses were performed (40 CFR § 122.41(j)(3)(iii));

4. The individual(s) who performed the analyses (40 CFR § 122.41(j)(3)(iv));

5. The analytical techniques or methods used (40 CFR § 122.41(j)(3)(v)); and

6. The results of such analyses. (40 CFR § 122.41(j)(3)(vi)) C. Claims of confidentiality for the following information will be denied (40 CFR § 122.7(b)):

1. The name and address of any permit applicant or Permittee (40 CFR § 122.7(b)(1)); and

2. Permit applications and attachments, permits and effluent data. (40 CFR § 122.7(b)(2))
V. STANDARD PROVISIONS – REPORTING
A. Duty to Provide Information
Permittees shall submit to the Santa Ana Water Board, State Water Board, or USEPA within a reasonable time, any information which the Santa Ana Water Board, State Water Board, or USEPA may request to determine whether cause exists for modifying, revoking and reissuing, or terminating this Order or to determine compliance with this Order. Upon request, the Permittees shall also submit to the Santa Ana Water Board, State Water Board, or USEPA copies of records required to be kept by this Order. (40 CFR § 122.41(h); Wat. Code, §13383)
B. Signatory and Certification Requirements

1. All applications, reports, or information submitted to the Santa Ana Water Board, State Water Board, and/or USEPA shall be signed and certified in accordance with Standard Provisions – Reporting Parts V.B.2, V.B.3, V.B.4, V.B.5, and V.B.6 below. (40 CFR § 122.41(k))

2. All permit applications shall be signed by either a principal executive officer or ranking elected official. For purposes of this provision, a principal executive officer of a federal agency includes: (i) the chief executive officer of the agency, or (ii) a senior executive officer having responsibility for the overall operations of a principal geographic unit of the agency (e.g., Regional Administrators of USEPA). (40 CFR § 122.22(a)(3))

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 314 of 320 Attachment F
Santa Ana Regional MS4 Permit

3. All reports required by this Order and other information requested by the Santa Ana Water Board, State Water Board, or USEPA shall be signed by a person described in Standard Provisions – Reporting Part V.B.2 above, or by a duly authorized representative of that person. A person is a duly authorized representative only if:
a. The authorization is made in writing by a person described in Standard Provisions – Reporting V.B.2 above (40 CFR § 122.22(b)(1)); b. The authorization specifies either an individual or a position having responsibility for the overall operation of the regulated facility or activity such as the position of plant manager, operator of a well or a well field, superintendent, position of equivalent responsibility, or an individual or position having overall responsibility for environmental matters for the company. A duly authorized representative may thus be either a named individual or any individual occupying a named position (40 CFR § 122.22(b)(2)); and
c. The written authorization is submitted to the Santa Ana Water Board and State Water Board. (40 CFR § 122.22(b)(3))

4. If an authorization under Standard Provisions – Reporting Part V.B.3 above is no longer accurate because a different individual or position has responsibility for the overall operation of the facility, a new authorization satisfying the requirements of Standard Provisions – Reporting Part V.B.3 above must be submitted to the Santa Ana Water Board and State Water Board prior to or together with any reports, information, or applications, to be signed by an authorized representative. (40 CFR § 122.22(c))

5. Any person signing a document under Standard Provisions – Reporting Parts V.B.2 or V.B.3 above shall make the following certification:
“I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.” (40 CFR § 122.22(d))

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 315 of 320 Attachment F
Santa Ana Regional MS4 Permit

6. Any person providing the electronic signature for documents described in Standard Provisions – Parts V.B.1, V.B.2, or V.B.3 above that is submitted electronically shall meet all relevant requirements of this Standard Provisions – Reporting Part V.B and shall ensure that all relevant requirements of 40 CFR part 3 (Cross-Media Electronic Reporting) and 40 CFR part 127 (NPDES Electronic Reporting Requirements) are met for that submission. (40 CFR § 122.22(e))
C. Monitoring Reports

1. Monitoring results shall be reported at the intervals specified in the Monitoring and Reporting Program (Attachment C) in this Order. (40 CFR § 122.41(l)(4))

2. Monitoring results must be reported in an Annual Report submitted to Santa Ana Water Board. All reports must be submitted electronically according to the Standard Provisions – Reporting Part V.J of this Attachment F and comply with 40 CFR part 3, 40 CFR section 122.22, and 40 CFR part 127. (40 CFR § 122.41(l)(4)(i))

3. If the Permittee monitors any pollutant more frequently than required by this Order using test procedures approved under 40 CFR part 136, or another method required for an industry-specific waste stream under 40 CFR subchapter N, the results of such monitoring shall be included in the calculation and reporting of the data submitted in the monitoring report specified by the Santa Ana Water Board or State Water Board. (40 CFR § 122.41(l)(4)(ii))

4. Calculations for all limitations, which require averaging of measurements, shall utilize an arithmetic mean unless otherwise specified in this Order. (40 CFR § 122.41(l)(4)(iii))
D. Compliance Schedules
Reports of compliance or noncompliance with, or any progress reports on, interim and final requirements contained in any compliance schedule of this Order, shall be submitted according to 40 CFR § 122.41(l)(5).

E. Twenty-Four Hour Reporting

1. Permittees shall report any noncompliance that may endanger health or the environment. Information shall be provided orally within 24 hours from the time the Permittee becomes aware of the circumstances. A written report shall also be provided within five (5) days of the time the Discharger becomes aware of the circumstances. The written report shall contain a

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 316 of 320 Attachment F
Santa Ana Regional MS4 Permit
description of the noncompliance and its cause; the period of noncompliance, including exact dates and times, and if the noncompliance has not been corrected, the anticipated time it is expected to continue; and steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance.

For noncompliance events related to combined sewer overflows, sanitary sewer overflows, or bypass events, these reports must include the data described above (with the exception of time of discovery) as well as the type of event (combined sewer overflows, sanitary sewer overflows, or bypass events), type of sewer overflow structure (e.g., manhole, combine sewer overflow outfall), discharge volumes untreated by the treatment works treating domestic sewage, types of human health and environmental impacts of the sewer overflow event, and whether the noncompliance was related to wet weather.

As of December 21, 2025 or a USEPA-approved alternative date (see 40 CFR § 127.24(e) or (f)), all reports must be submitted electronically outlined in Standard Provisions – Reporting Part V.J of this Attachment F. The reports shall comply with 40 CFR part 3, 40 CFR section 122.22, and 40 CFR part 127. (40 CFR § 122.41(l)(6)(i))

2. The following shall be included as information that must be reported within 24 hours under this paragraph (40 CFR § 122.41(l)(6)(ii)):
a. Any unanticipated bypass that exceeds any effluent limitation in this Order. (40 CFR § 122.41(l)(6)(ii)(A))
b. Any upset that exceeds any effluent limitation in this Order. (40 CFR § 122.41(l)(6)(ii)(B))
c. Any violation of a maximum daily discharge limitation for any of the pollutants listed by the Santa Ana Water Board in this Order. (40 CFR § (l)(6)(ii)(C) and 122.44(g))

3. The Santa Ana Water Board may waive the above-required report under this provision on a case-by-case basis if an oral report has been received within 24 hours. (40 CFR § 122.41(l)(6)(iii))
F. Planned Changes
Permittees shall give notice to the Santa Ana Water Board as soon as possible of any planned physical alterations or additions to the permitted facility. Notice is required under this provision only when (40 CFR § 122.41(l)(1)):

23.C

Order R8-2024-0001 (NPDES No. CAS618000) Page 317 of 320 Attachment F
Santa Ana Regional MS4 Permit

1. The alteration or addition to a permitted facility may meet one of the criteria for determining whether a facility is a new source in 40 CFR section 122.29(b) (40 CFR § 122.41(l)(1)(i)); or

2. The alteration or addition could significantly change the nature or increase the quantity of pollutants discharged. This notification applies to pollutants that are not subject to the effluent limitations in this Order. (40 CFR § 122.41(l)(1)(ii))
G. Anticipated Noncompliance
Permittees shall give advance notice of any planned changes in the permitted facility or activity that may result in noncompliance with this Order’s requirements. (40 CFR § 122.41(l)(2))
H. Other Noncompliance
Permittees shall report all instances of noncompliance not reported under Standard Provisions – Reporting Parts V.C, V.D, and V.E above at the time monitoring reports are submitted. The reports shall contain the information listed in Standard Provision – Reporting V.E above. For noncompliance events related to combined sewer overflows, sanitary sewer overflows, or bypass events, these reports shall contain the information described in Standard Provision – Reporting Part V.E above and the applicable required data in Appendix A to 40 CFR part 127. The Santa Ana Water Board may also require the Permittee to electronically submit reports not related to combined sewer overflows, sanitary sewer overflows, or bypass events under this section. (40 CFR § 122.41(l)(7))
I. Other Information
When the Permittee becomes aware that it failed to submit any relevant facts in a permit application or submitted incorrect information in a permit application or in any report, the Permittee shall promptly submit such facts or information. (40 CFR § 122.41(l)(8))
J. Initial Recipient for Electronic Reporting Data
The owner, operator, or the duly authorized representative is required to electronically submit NPDES information specified in Appendix A to 40 CFR part 127 to the initial recipient defined in 40 CFR section 127.2(b). USEPA will identify and publish the list of initial recipients on its website and in the Federal Register, by state and by NPDES data group (see 40 CFR § 127.2(c)). USEPA will update and maintain this listing. (40 CFR § 122.41(l)(9))