La Palma City Council
June 2, 2026

1 TO: City of La Palma
7822 Walker St.

La Palma, CA 90623
Jake Chavira
714-690-3312
[email protected]

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DATE: 3/18/26 QUOTE #:P2603041 REVISION 0

SUBJECT: Mn Removal Pilot Study
REFERENCE: City of La Palma

WE ARE PLEASED TO OFFER OUR QUOTATION ON THE FOLLOWING

ITEM QTY DESCRIPTION UNIT PRICE EXTENDED
1 LOT PUREFLOW FILTRATION DIV. - MOBILE PILOT LABORATORY STUDY

Field pilot study for the removal of manganese from groundwater, including: one (1) mobile pilot filter laboratory; one (1) qualified Pureflow technician for up to 5-days; mobilization / demobilization; pilot study protocol; and related equipment to examine optimal operation and maintenance scenarios for the removal of manganese using Pureflow PM200 permanent catalytic adsorptive media down stream of oxidation feed.

A pilot study report detailing the treatment goals, performed treatment scenarios, optimization of selected scenarios, onsite water quality testing, laboratory testing, conclusions and recommendations.

Notes:
1) Laboratory testing fees to verify field results will be by the city 2) Inlet water to and drain from the trailer by others
3) Two (2) 120V, 20-amp circuits at the job site are required 4) Secure & safe location to stage the mobile pilot laboratory are required 5) Review Pureflow Bulletin for our suggested protocol for Mn/Fe removal ……………….. $11,500.00
NOTE: PRICE(S) DOES (DO) NOT INCLUDE ANY TAX UNLESS SPECIFICALLY NOTED PAYMENT TERMS:

APPROX. DATE OF SHIPMENT: TBA
EST. SHIPPING WEIGHT: TBD
F.O.B.: Shipping Point, Pre-Pay & Add
PUREFLOW FILTRATION DIV.

By: Title: VP Date: 3/18/2026
Please sign and return
Accepted by: Title: Date:

Prices specified herein are exclusive of all taxes unless specifically noted This proposal is subject to all terms and conditions printed on face and reverse side

QUOTATION
6739 Washington Ave.

Whittier CA 90601
[email protected]
+1 562 945 3425
+1 800 926 3426
www.waterbypureflow.com
Print Name, Title, & Date
Print Name, Title, & Date
Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

2 PUREFLOW FILTRATION DIV. QUOTATION STANDARD TERMS AND CONDITIONS OF SALE

1. AGREEMENT. The terms and conditions set forth below and on the front side hereof constitute the entire Agreement between the customer named on the front side hereof ("Buyer") and Pureflow Filtration Div., and Pureflow Ozone Div., divisions of California Environmental Controls, Inc., a California corporation ("Seller").

2. TERMS OF SALE. (a) TAXES: Unless specifically provided on the front side hereof, prices specified herein on the Goods are exclusive of all local, state, and federal taxes including without limitation taxes on manufacturing, sales, receipts, gross income, occupation, use and all similar taxes, or other taxes of any nature. Wherever applicable, such taxes will be invoiced as a separate charge which Buyer agrees to pay the Seller. (b) TERMS OF PAYMENT: Net cash due upon receipt of invoice, unless noted on front side of this quotation, to approved credit accounts. The Buyer agrees to pay Seller an additional charge of one and one-half percent (1 and 1/2%) per month (or such lesser amount equal to the maximum rate permitted by law) on any invoices not paid according to these terms. (c) SECURITY INTEREST: Until payment in full of the purchase price therein specified, Seller reserves a security interest in the goods securing payment of such purchase price. (d) DELIVERY: Prices quoted are f.o.b. point of origin of shipments unless shipping is specifically included in price offered on front page. Prices include domestic packing for rail or commercial shipments only. Shipment and delivery dates are estimates based upon schedules of Seller's suppliers and are computed from the time of settlement of all details and receipt of full approval of drawings where drawing approval is required. (e) Field Supervision: Unless specifically provided on the front side hereof, no installation assistance or field supervision by Seller is included in the terms and conditions of this Agreement.

3. ENTIRE AGREEMENT. This agreement supersedes all previous representations, statements, promises, agreements or understandings, written or otherwise. This Agreement is intended by the parties as a final expression of their understanding and no casual or prior dealings shall be relevant to explain any of the terms or conditions hereof. The Seller shall not be bound by any agent’s or employee’s representations, promises, statements or inducements not set forth in the Agreement. If any inconsistency exists between any typed or handwritten materials on the front hereof and these Standard Terms and Conditions, the former shall be controlling.

4. ACCEPTANCE. This quotation is an offer upon the terms and conditions herein specified. Acceptance by the Buyer may be effected by signing a copy of this quotation where specified and returning same to the Seller, or by the Buyer issuing a purchase order and delivering same to the Seller, which shall constitute Buyer's acceptance of this quotation and all of the terms and conditions herein specified. Acceptance of this offer is limited to its terms. Acceptances or confirmation which state additional or different terms from this offer shall be operative as acceptances; provided, however, that all such additional or differing terms shall be deemed material alterations within the meaning of Section 2207 (2) (b) of the California Commercial Code and notice of objection to them pursuant to Section 2207 (2) (c) of the California Commercial Code is hereby given.

5. CANCELLATION. Orders may be cancelled by the Buyer only with Seller's written consent and upon payment of reasonable and proper cancellation charges, including factory costs and expenses.

6. INSPECTION. Buyer agrees to inspect the goods, supplies, merchandise, and material covered hereby ("Goods") immediately upon their receipt by Buyer, secure a written acknowledgement from the delivering carrier as to any loss or damage and within three (3) business days of their receipt to give written notice to the Seller of any claim that the Goods do not conform with the terms of the Agreement. Failure to make such a claim within the stated period shall constitute an irrevocable acceptance of the Goods and an admission that they fully comply with all of the terms and conditions of the Agreement. Buyer expressly waives any right it may have to revoke acceptance after such three (3) day period.

7. DELAYS. Seller shall not be liable for any delays or failures in making shipments or deliveries caused by any contingency beyond Seller's control, or the control of Seller's suppliers or manufacturers, including without limitation failures or delays brought about by, caused by or in any manner arising from (i) labor conditions including strikes and shortages of labor, (ii) shortages of fuel, power, material or supplies, (iii) transportation delays, (iv) acts of God, fires, floods or weather problems, (v) damage to, or destruction in whole or in part of Goods, vehicles or manufacturing plants, (vi) accidents, or (vii) riots, government interference, embargos, regulations, war, insurrection or terrorist acts. The non-occurrence of the above contingencies with respect to Seller, its suppliers and manufacturers is a basic assumption of this agreement.

8. DELAY IN INSTRUCTIONS. Buyer agrees to furnish complete shipping instructions in such a manner as to reach the Seller at its main office ten (10) days before the date for any shipment specified herein.

Buyer's failure to so furnish complete shipping instructions shall, without notice, automatically extend the shipping date from day to day until the Buyer furnishes complete shipping instructions, or until the Seller exercises its right to terminate the Agreement.

9. RISK OF LOSS. Unless Buyer and Seller specifically agree in writing to modify the terms of Paragraph 2. (d), above, all risk or loss shall pass to the Buyer when Goods are delivered by Seller to the carrier. In the event that Buyer and Seller agree in writing that the Goods are sold f.o.b. destination, Seller’s responsibility for loss or damage terminates upon tender of delivery to Buyer by the carrier and the written acknowledgement and claims procedure provided for in Paragraph 4, above, shall be a precondition to any claim by Buyer for loss of damage in transit.

10. RETURNS. In no case are any Goods to be returned to Seller without first obtaining the written permission of Seller, which permission Seller may refuse to give at Seller's sole discretion. Only standard unused Goods as currently manufactured or inventoried by Seller which have been invoiced to Buyer within the previous ninety (90) days will be considered by Seller for return. Special items manufactured to order may not be returned under any circumstances. Goods which Seller accepts for return and credit will, in any event, be subject to a minimum handling and service charge of 25% plus all transportation charges. All returned Goods, if Seller accepts the return thereof, must in any case be securely packaged and shipped, freight prepaid, and the risk of loss shall remain with Buyer until the Seller actually receives the Goods.

11. DEFAULTS. In the event Buyer fails to comply with any of the terms of the Agreement or becomes bankrupt or insolvent or Buyer's financial condition becomes impaired or unsatisfactory to Seller, Seller may do any or all of the following: (a)Terminate the Agreement upon written notice thereof to Buyer without prejudice to Seller's rights to receive any amount then due under the Agreement; (b) Withhold all further deliveries under the Agreement; (c) require that Buyer pay for all future shipments in advance or provide other satisfactory security or guarantees to Seller that all existing and future invoices will be paid on or before their due dates; (d) Make partial shipments only to Buyer, which Buyer agrees to accept; (e) Recall any Goods then in transit and retake the same and repossess all Goods which may be stored with Seller in which case Buyer consents that all Goods so recalled, retaken or repossessed shall become the absolute property of Seller, provided that Buyer is given full credit therefor; (f) Upon written notice to Buyer revise the stated credit terms, if any, contained in this Agreement; (g) Without limitation, exercise any rights or remedies available to Seller under the Uniform Commercial Code as in force and effect on the date of the Agreement; or (h) Without limitation, exercise any other rights or remedies available to Seller under any applicable federal, state or local law.

12. ATTORNEY'S FEES. In the event of a default by Buyer of any of the terms or conditions of the Agreement, Buyer agrees to pay all costs of collection and enforcement incurred by Seller including, without limitation, Seller's reasonable attorney's fees and court costs.

13. RETENTION LIMITATION. Retention, if any is accepted by Pureflow Filtration Div., shall be limited to a maximum of ten percent (10%) of the contract price. All monies retained shall be paid, in full, upon successful “start-up” of the equipment supplied, or ninety (90) days after shipment of said goods, whichever date first occurs. The payment of monies retained under the terms of this paragraph is not conditioned upon any factors, issues, events or contingencies which are not specifically delineated in this quotation. The right of Pureflow Filtration Division to payment is NOT subject to any payment provisions enforced upon Buyer by the terms of any other contract with either Pureflow or a third party.

14. CONSEQUENTIAL / LIQUIDATED DAMAGES. The Buyer agrees that notwithstanding the form in which any legal or equitable action, proceeding or position may be brought or asserted by Buyer against Seller including without limitation claims based upon actual or alleged delays or breaches of warranty, that Seller's liability, if any, arising out of or in any way related to this Agreement, shall be limited to actual money damages in an amount not to exceed the total amount actually paid for the Goods by Buyer. Buyer further agrees that seller shall not, in any event, be liable for indirect, special, consequential or liquidated damages or penalties, whether based upon contract, warranty, tort, or negligence.

15. PROPRIETARY MATERIAL. All drawings, patterns, specifications, and information included in this proposal, and all information otherwise supplied by Pureflow Filtration Div. relating to the design, erection, operation, and maintenance of the goods, including filter media and all treatment processes, is the proprietary and / or confidential material or information of Pureflow Filtration Div. Purchaser shall not disclose such material or information to others or allow others to use such material or information without express written permission from an officer of Pureflow Filtration Div.

16. GOVERNING LAW / CONSENT TO JURISDICTION. (a) The terms and conditions set forth herein shall be construed under and in accordance with the laws of the State of California. The parties hereto consent to the jurisdiction and venue of any court of general jurisdiction in the Southeast District of Los Angeles County and the United States District Court for the Central District of California, with respect to any proceedings arising out of or in connection with the Agreement or any purchase hereunder, and further agree that mailing to either party by certified or registered mail shall constitute lawful and valid service of process. (b) No Waiver: No waiver by Seller of any default by Buyer shall be deemed a waiver of any subsequent default by Buyer. (c) Severability: Should any of the terms or conditions of the Agreement be declared invalid or unenforceable, it shall not affect the validity or enforceability of any of the remaining terms and conditions.

17. VALIDITY. The price quoted is firm for thirty (30) days, unless otherwise identified on the front of this quotation.

18. ERRORS. Pureflow Filtration Div. and Pureflow Ozone Div. of California Environmental Controls, Inc. reserves the right to correct or identify any scrivener’s errors including, but not limited to typographical, clerical or dictation errors, in the quotation without any liability to Pureflow Filtration Div. or Pureflow Ozone Div., of California Environmental Controls, Inc.

19. TECHNICAL ADVICE. Upon Buyer's request, Seller may furnish technical advice with reference to the use of the material sold hereunder, to such extent as Seller has such information conveniently available; however, it is expressly agreed that there is no obligation to furnish any such advice, and that if any advice or assistance is furnished, which will be without charge, it shall be given and accepted at Buyer's risk, and Seller shall not be responsible or liable for the advice or assistance given or results thereof.

20. WARRANTIES: Except as provided below, Seller warrants that equipment or parts thereof delivered hereunder meet Sellers' standard specification for the equipment or parts, or such other specifications as have been expressly made as part of this Agreement. Equipment and parts sold, but not manufactured, by Seller are warranted to the extent of the manufacturer's original warranty. THERE ARE NO OTHER WARRANTIES, EXPRESSED OR IMPLIED. SELLER MAKES NO WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. THE BUYER WILL MAKE NO WARRANTY OR MODIFY ANY EXISTING WARRANTY TO ANY CUSTOMER BEYOND ANY WARRANTY STATED BY SELLER'S SPECIFICATIONS. NO LIABILITY WILL RESULT TO EITHER PARTY FROM DELAY IN PERFORMANCE OR NON-PERFORMANCE CAUSED BY CIRCUMSTANCES BEYOND THE CONTROL OF THE PARTY AFFECTED. THE MEASURE OF DAMAGES RECOVERABLE BY BUYER SHALL NOT EXCEED THE PURCHASE PRICE PAID BY BUYER TO SELLER. THIS IS BUYER'S SOLE REMEDY AGAINST SELLER. SELLER SHALL NOT BE LIABLE FOR ANY INDIRECT OR PROSPECTIVE, CONSEQUENTIAL OR SPECIAL DAMAGES NOTWITHSTANDING THE FOREGOING. NO EQUIPMENT OR PARTS SHALL BE RETURNED WITHOUT INSTRUCTIONS FROM SELLER'S HOME OFFICE.

PF601.5
Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

6739 Washington Ave. Whittier CA 90601
www.waterbypureflow.com
[email protected]
+1 562 945 3425
+1 800 926 3426
Bulletin No. A2.090309.6
1 2
3 Suggested Pilot Filter Study Protocol for The Removal of Arsenic, Iron, & Manganese Using Coagulation / Filtration Process
Description of The Pilot Study
A. Pilot Study Goals / objections

• To verify the effectiveness of the process in removing / reducing contaminants, including: arsenic (As), iron (Fe), and manganese (Mn) in the raw well water to the following United States Environmental Protection Agency (USEPA) Maximum Contaminant Levels (MCL) (See Note 1).

Arsenic ……………………………. < 10 μg / l
Iron .................................... < 0.30 mg / L Manganese ........................ < 0.05 mg / L
• Select the most effective filter media (see note 2).
• Determine chemical usage requirements including oxidant; e.g., sodium hypochlorite (NaOCI), co-precipitant; e.g., ferric salts, such as ferric chloride (FeCl3) / ferrics sulfate (Fe2[SO4]3), and any other process specific chemicals, such as acid and or caustic to adjust pH. • Determine pre and post filter chemical dosage rates including oxidant e.g., sodium hypochlorite (NaOCl), co-precipitant, e.g., ferric salts, such as ferric chloride (FeCl3) / ferric sulfate (Fe2[SO4]3), and if any other process specific chemicals, such as acid, and / or caustic are required to adjust the pH. • Determine the most effective and economical filtration rate (gpm/ft2 of media) that will achieve the treatment goals and provide an effective bashwash to filtration ratio. • Define the frequency and duration for the filter backwash cycles. • Provide an accurate estimate of long-term operating costs.

Notes: 1. State and or utility MCL may be lower than the EPA MCL.

2. Raw water quality data and or field testing may indicate a requirement to test multiple media types

3. Varying contaminant levels in the raw water may require an automated pilot filter to test 24/ hrs / day for extended periods.

Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

Notes:

1. If residual solids settling time is unacceptable, determine what flocculant and dosage rate is required to cause the sludge to settle within the required time.

2. Water must be taken from a valve located in teh water main immediately downstream from the well pump. Do not pump well water from a storage tank to the pilot filter(s).

C. Field Sampling
In addition to field testing of water quality, raw and filtered water "grab samples" will be sent to qualified independent laboratories for verification of field tests. Samples will be taken at significant intervals and should include the following: filtration without ferric salt feed, filtration with ferric salt feed, filtration without pH adjustment, filtration with pH adjustment, and filtration performance at the optimized filter flow and chemical feed rates.

Notes:

1. The responsibility for payment of laboratory testing should be determine before pilot testing begins, e.g., client / consulting engineer / contractor.

2. Sampling complexity and frequency to be determined before starting.

3. Refer to Pureflow filtration Div. Bulletin NO. T2.9422.7 Arsenic, Iron, and Manganese General mineral Analysis for sampling protocol.

4. Chlorine break point must be established and chlorine residual must be on the plus side of break point before filtred water samples are taken.

D. Pilot Filter and Laboratory Test Equipment (Suggested Minimum Two (2) ________" I.D. pilot filter with control valves (manual / automatic), effluent and backwash water flow meters, pressure gauges, and raw / treated water sampling valves.

Note: A minimum of two (2) 3" I.D. pilot filter columns is recommended. Other commonly accepted filter sizes are 6", 12", 24", 36", and 48" depending on job site requirements / pilot study protocol.

Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

6739 Washington Ave. Whittier CA 90601
www.waterbypureflow.com
[email protected]
+1 562 945 3425
+1 800 926 3426
Bulletin No. A2.090309.6
Note: Optimum filter backwash frequency and backwash water sludge settline will be tested each day of the pilot study.

Four (4) Chemical feed pumps with digital controls to feed: sodium hypochlorite, ferric salt (e.g., ferric chloride), acid (sulfuric, H2SO4) and caustic (sodium hydroxide, NaOH) One (1) Colorimeter with chemical reagents (for free and total chlorine, iron, and manganese) One (1) Low range arsenic test kit
One (1) pH meter
One (1) Hydrogen sulfide (H2S) test kit (AWWA standard) One (1) Thermometer (water temperature monitoring)
One (1) Turbidimeter (NTU)
E. Daily Test Operations
Day 1
Equipment setup and calibration. Determine optimum chemical dosage rate to reach chlorine break point. Test for the reduction of arsenic, iron, and manganese levels, without the addition of ferric salt or acid.

Days 2 & 3
a) Determine optimum ferric salt dosage rate and continue testing for other optimum chemical dosage rates (and contaminant removal) and determine how arsenic concentration varies with ferric salt dosage.
b) Determine optimum pH for the removal of contaminants. c) Determine optimum filter flux. (Flow rate in gpm / ft 2 of media) d) Determine caustic dosage (e.g. sodium hydroxide), if required, to provide water that is non- corrosive, downstream of the filter.

Days 3 & 4
Determine contaminant removal at various filtration rates, at optimum chemical dosage rates. Confirm chlorine dosage rate required to provide the required disinfectant / free chlorine residual past the filter.

Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

Day 5 Continue testing, if required.

Notes:

1. Minimum recommended testing period is three (3) days.

2. Notify city personnel each day when meaningful sampling can be performed by city staff and Pureflow field personnel.

3. Laboratory testing must follow AWWA standards including sample bottle type / preparation.

Please refer to Bulletin No. T2.944 Pureflow General Mineral Analysis and Design Data Bulletins (arsenic, iron, and manganese), for our recommended field and laboratory water quality test procedures.

4. At least two (2) samples of filtered water must be taken at each sampling interval. The Client will take one (1) of the samples. The other one (1) samples are to be sent to two (2) separate, qualified, laboratories by the filter manufacturer and / or consulting engineer.

5. If the results of field testing for arsenic are not verified by the laboratory test results, additional on-site testing may be required.

6. We suggest contacting the local water analytical laboratory, in advance of the pilot testing, to have them provide a minimum twenty-four hour "turnaround" of the test results.

7. Disposal of well water must be considered before pilot testing.

8. Well should be pumped at design flow rate during pilot testing to assure that the raw water quality being tested is the same that the full-scale filter will treat.

F. Pilot Filter Study Report
The pilot filter study report must be comprehensive, include data pertinent to the particular well and / or wells that are to be treated, and must include the following data as a minimum:
• A brief description of the field conditions and existing water well / treatment equipment • An executive summary
• List of field personnel on site during testing
• Description of the pretreatment equipment, filtration system and accessories used to run the pilot test • Photographs of the site / test equipment
•Copies of field-testing data sheets for each day on the well site • Break point chlorination curve
• Water quality test analytical methods
• Field operation procedures
• Discussion of pilot test results
• Tables indicating test results & contaminant removal using various media, oxidant dosage rates, & pH levels • pH (pre-filter and post-filter)
• Filter vessel pressure losses at various time intervals • Chemical feed rates vs. contaminant removal
Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

6739 Washington Ave. Whittier CA 90601
www.waterbypureflow.com
[email protected]
+1 562 945 3425
+1 800 926 3426
Bulletin No. A2.090309.6
• Filter column configuration including :
* Support media *Active media *Column diameter / height *Backwash loading rate & duration *Filter run time *Total media depth *Filter run time before contaminant breakthrough *Filter area (sq. ft. media) • Raw water vs. filtered water quality
• P & ID of pilot filter test process
• Chart showing pressure drop as a function of run time • Backwash water mass recoveries (CA requires Toxicity Characteristic Leaching Procedure W.E.T. Test) • Conclusions

THE FOLLOWING DATA CAN ALSO BE PROVIDED WITH THE PILOT STUDY WHEN REQUESTED BY THE CLIENT / CONSULTING ENGINEER:
• Recommended treatment process, including P & ID and the dimensions of the area required to install the treatment process.
• Operation and maintenance costs of recommended treatment process, including daily chemical consumption, and estimated daily chemical cost.
• Budget proposal for treatment process.

COMMENTS
a) The above information is offered as a guide to prepare a comprehensive protocol for a pilot test filter study to remove arsenic, iron, and manganese from drinking water supplies and industrial applications using a coagulation / filtration (permanent media) filtration system. Other contaminants such as hydrogen sulfide, ammonia (NH3), total organic carbon (TOC), etc. can affect the removal of the primary contaminants, and / or the effective filter run time and must be considered during the planning and operation stages of the pilot filter test so that these contaminants are removed along with the primary contaminants.

Note: If arsenic is the primary contaminant to be removed from the drinking water supply and the use of Disposable Media is under consideration, other contaminants (such as iron, manganese, sulfides, organics, chromium [Cr], silica [Si], phosphates [e.g., sodium phosphate, NaH2PO4], etc.) will also affect the removal of arsenic by occupying the surface of the media intended to remove arsenic. This will reduce the effective life of the disposable Media, increase the disposal frequency of the media and, the cost of operation.
b) Potential seasonal variance of contaminants must be considered when evaluating pilot filter test results.

Wells that are subject to substantial increase / decrease in contaminants should be tested when the contaminant levels are highest. Short term testing can result in questionable test results if contaminant variation is not considered.

Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

c) The cost of pilot testing should be considered when writing a pilot filter study protocol. Comprehensive pilot testing often requires more field personnel, increased sampling and laboratory analysis costs, and also increased pilot test report complexity and costs.
d) Pureflow recommends that clients discuss the proposed pilot filter study protocol with a consulting engineer and their local Department of Health Services (DHS) officer before the protocol is finalized and field testing begins.
e) If a generator is required to provide power for the pilot trailer, refer to teh Pureflow Pilot Trailer Data Sheet for power requirements.
f) The pilot trailer and ancillary equipment must be protected by a security fence or gated facility. g) Refer to Pureflow pilot Trailer data Sheet for operating parameters. h) Contaminants such as trihalomethanes (THM), or color in the raw water may require an alternate oxidant such as ozone. Chlorine would be fed to provide a disinfecting residual downstream of the filter system. i) Client, contractor, or consulting engineer must provide adequate property insurance to cover the replacment cost of the pilot trailer and testing equiment.

TREATABILITY STUDY
As an alternate to a comprehensive pilot filter study, water purveyors and consulting engineers can also consider a "Treatability Study". This test is performed at the well site and is generally run with a small diameter pilot filter column (e.g., 3" I.D.), and operated to gather basic data to determine the ability of the process / filter media to remove arsenic, iron, and manganese.

The pilot test data and report are simple, are usually operated for one (1) to three (3) days and are also much less expensive than a comprehensive pilot test study. "Treatability Studies" are sometimes run prior to a comprehensive pilot test to determine / confirm basic raw water quality and treatment data in order to write a pilot test protocol that is designed for the specific parameters of the raw water to be filtered.

Bench Testing
Small-batch water samples can be tested in a laboratory using multi-position, variable speed har testing equipment to simulate chemical mixing, flocculation, and settling conditions in a full scale WTP, and/or small diameter filter columns (typically 1“ to 2“ diameter). Testing protocol should be established using AWWA standards as a guide. Water should be tested within 24 hours from the time the water samples were taken.

Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

[email protected]
(800) 926-3426
6739 Washington Ave. / P.O. Box 469
Whittier, CA 90608-0469
(562) 945-3425
[email protected]
www.waterbypureflow.com
Contact
Docusign Envelope ID: 7F4325DD-6438-870A-83DF-8614D3955648

Agenda Item No. 10 June 2, 2026 | 1
City of La Palma
Agenda Item No. 10
MEETING DATE: June 2, 2026
TO: City Council
FROM: City Manager
SUBMITTED BY: Jake Chavira, Acting Community Development & Public Works Director
AGENDA TITLE: Authorize Payment to Kordich Construction Inc. for La Palma Avenue/Rose Street Watermain Break Repair
RECOMMENDED ACTION:

Authorize the City Manager to approve payment in the amount of $70,670.44 to Kordich Construction Inc. for the La Palma Avenue/Rose Street watermain break repair.

BACKGROUND:

On April 30, 2026, at approximately 3:30 p.m., a watermain break occurred near the intersection of La Palma Avenue and Rose Street. The incident affected water service and pressure for approximately 10 residential households located on Park West Circle east of Bravo Lane.

Kordich Construction Inc. was mobilized to perform the emergency excavation and watermain repair work necessary to restore the damaged watermain. The contractor worked alongside the City's Water Division and Public Works staff throughout the repair process. Repair efforts continued throughout the day and into the evening as crews excavated the damaged section of pipe and installed a replacement section to restore the watermain. Specialized materials and replacement components were required to complete the repair work safely and efficiently.

During the repair operations, approximately 10 households experienced reduced water pressure for basic use until the repair reached the final replacement stage, at which time water service was temporarily shut off to allow welding and installation of the new pipe section. Public Works coordinated with a nearby agency to provide a porta-potty as a temporary measure for affected residents, and Water Division staff personally visited each impacted home to provide updates and assistance during the outage.

While the repair work was being completed, Water Division staff also responded to brown water calls and conducted flushing operations throughout the affected area to address water quality concerns resulting from the watermain break and repair activities. Kordich Construction Inc. also assisted with site safety measures, excavation operations, and coordination necessary to maintain emergency access and minimize disruption to the surrounding neighborhood. The emergency repair work required a temporary right-lane closure on La Palma Avenue, which remained in place following the repair until roadway restoration activities could be completed safely.

Agenda Item No. 10 June 2, 2026 | 2
The emergency water main repair was completed on May 1, 2026, at approximately 6:40 p.m., at which time normal water service was fully restored to the affected residences.

FISCAL IMPACT:

The total not-to-exceed amount for these services is $70,670.44. Funding for the emergency water services is available in the FY 2026-27 Budget in the Water Fund (050-460-6000-00000).

ENVIRONMENTAL IMPACT:

Authorize Payment to Kordich Construction Inc. for La Palma Avenue/Rose Street Watermain Break Repair is not a project for purposes of the California Environmental Quality Act (CEQA) pursuant to Cal. Pub. Res. Code § 21065 and pursuant to CEQA Guidelines 15306 and 15061(b)(3) as basic data and information collection, and as it can be seen with certainty that this activity will not have a significant effect on the environment.

ATTACHMENTS:

1. Kordich Construction Inc. Invoice for La Palma Avenue/Rose Street Water Mainbreak

Agenda Item No. 11 June 2, 2026 | 1
City of La Palma
Agenda Item No. 11
MEETING DATE: June 2, 2026
TO: City Council
FROM: City Manager
SUBMITTED BY: Jake Chavira, Acting Community Development & Public Works Director
AGENDA TITLE: 2026 Annual Water Quality Report
RECOMMENDED ACTION:

Receive and file the 2026 Annual Water Quality Report and direct staff to distribute the report to the City of La Palma residents and businesses.

SUMMARY:

Since 1990, California public water utilities have been providing an Annual Water Quality Report to their customers. This year’s report is expected to be delivered to residents by July 1st and covers drinking water quality testing and reporting for calendar year 2025. The City of La Palma Public Works Water Division vigilantly safeguards its water supply and, as in years past, the water delivered to homes met the water quality standards required by Federal and State regulatory agencies. The United States Environmental Protection Agency (EPA) and the State Water Resources Control Board (SWRCB) are the agencies responsible for establishing and enforcing drinking water quality standards. This report has no significant changes from the previous Water Quality Report. In addition, though rarely used, this report includes water quality data from the Metropolitan Water District (MWD).

BACKGROUND:

The California Domestic Water Quality and Monitoring Regulations (Title 22 of the California Code of Regulations) requires that each community’s water system distribute to each customer an Annual Water Quality Report on the water purveyed. Additionally, the U.S. EPA's Consumer Confidence Rule requires public water suppliers that serve the same customers throughout the year to provide Consumer Confidence Reports (CCR) to their customers. These reports are also known as annual water quality reports or drinking water quality reports.

Attached is the Annual Water Quality Report that updates the City Council on the current water quality and future issues facing the City of La Palma (City). The City’s current potable water quality is safe to drink.

ANALYSIS:

Since the 1960’s, there have been reports of mild water coloration. This is a result of metals in the

Agenda Item No. 11 June 2, 2026 | 2
groundwater, such as iron and manganese. These metals occur naturally in soils, rocks, and minerals.

In the aquifer, when groundwater comes into contact with these solid materials, the materials begin to dissolve and release constituents that cause color issues in the water. Red and brown colors are due to iron; black is due to manganese, while yellow is due to dissolved organic matter such as tannins. Currently, iron and manganese are categorized as a Secondary Drinking Water Standard, which are not health-threatening, non-enforceable guidelines to help regulate contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. As such, the EPA and the SWRCB have not issued public health goals nor required maximum contaminant level goals for these constituents because secondary standards are set on the basis of aesthetic concerns. In the event an agency surpasses the recommended maximum contaminant level (MCL) for secondary drinking water standards, the agency notifies its governing board. At this time, there are no MCL concerns for iron or manganese to report. For example, the manganese MCL is set at 50 parts per billion (ppb), and the local groundwater levels are at 42 ppb.

Arsenic is a semi-metal element that has been detected in the City’s groundwater since the 1960’s.

It is odorless and tasteless. It can enter drinking water supplies from natural deposits in the earth, through agricultural activities, or industrial practices. According to the Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency, ingestion of arsenic can pose a risk of cancer (such as lung and urinary bladder cancer) of up to one excess case of cancer per million people per 70-year lifetime. At higher levels of exposure, arsenic can also result in a number of non-cancerous issues, such as vascular or skin effects.

Arsenic is a Primary Drinking Water Standard. As a result, primary standards are legally enforceable standards that apply to public water systems and require water agencies to protect public health by limiting the levels of contaminants in the drinking water. Therefore, the State of California revised the arsenic MCL from 50 to 10 ppb on November 28, 2008. Amongst the City’s two well sites, the City Yard Well is currently at 6.8 ppb. Concentrations of arsenic have been mainly detected at the City Yard well site and have been as high as 9.3 ppb. Therefore, future treatment is imminent.

Per- and polyfluoroalkyl
Per- and polyfluoroalkyl (PFAS) substances are a group of thousands of manmade chemicals that are used to make carpets, clothing, fabrics for furniture, food packaging, cookware, and other materials to make them non-stick and/or resistant to water, oil, and stains. They are also used in a number of industrial processes and firefighting activities. According to the EPA, current peer-reviewed scientific studies have shown that exposure to certain levels of PFAS may lead to reproductive effects such as decreased fertility or increased high blood pressure in pregnant women. As such, the Safe Drinking Water Act (SDWA) requires that the EPA issue a list of unregulated contaminants to be monitored by public water systems every 5 years. The City is currently complying with the fifth Unregulated Contaminant Monitoring Rule (UCMR 5), published on December 27, 2021. UCMR 5 requires sample collection for 30 chemical contaminants between 2023 and 2025 using analytical methods developed by EPA and consensus organizations. This action provides EPA and other interested parties with scientifically valid data on the national occurrence of these contaminants in drinking water. Consistent with EPA’s PFAS Strategic Roadmap, UCMR 5 will provide new data critically needed to improve EPA’s understanding of how often 29 PFAS (and lithium) are found in the nation’s drinking water systems and at what levels. This data will ensure science-based decisionmaking and help prioritize the protection of disadvantaged communities. This data will ensure sciencebased decision-making and help prioritize various health protections.

The City of La Palma last sampled for PFAS in 2025. All sample results were Non-Detect (ND). The City is currently scheduled to sample both wells for PFAS this year.

For the Orange County Groundwater Basin, PFAS primarily enters via the Santa Ana River, where

Agenda Item No. 11 June 2, 2026 | 3
flows infiltrate into the basin. This occurs through discharges of treated wastewater and stormwater runoff from upstream communities in San Bernardino and Riverside counties. Chemical manufacturers are the original source of PFAS chemicals. Despite playing no role in releasing PFAS into the environment, cities and water agencies must find ways to remove them from their local water supply. This can be accomplished by blending clean water into the system to reduce contaminants or by constructing treatment facilities. Fortunately, as a groundwater partner agency of the Orange County Water District (OCWD), OCWD will cover the full cost of local treatment facilities and 50% of maintenance costs in the event PFAS is detected.

FISCAL IMPACT:

The cost to prepare, design, and print the 2026 Water Quality Report is approximately $6,200, with an additional postage cost of approximately $1,300. The FY 2025-26 Budget (050-430-6540-00000; 050-440-6520-00000) contains sufficient funding to cover all associated costs.

ATTACHMENTS:

1. 2026 Water Quality Report

This report reflects water quality testing conducted during 2025. 2026
Este informe contiene información muy importante sobre su agua potable. Tradúzcalo o hable con alguien que lo entienda.

This report contains important information about your drinking water. Translate it, or speak with someone who understands it.

Presented By
City of La Palma
Community Development
& Public Works Department

Source Water Assessment
Imported (MWDSC) Water Assessment
Every five years, MWDSC is required
by DDW to examine possible sources
of drinking water contamination in
its State Water Project and Colorado
River source waters. The most recent
surveys for MWDSC’s source waters
are the Colorado River Watershed
Sanitary Survey—2022 Update and
the State Water Project Watershed Sanitary Survey—2021
Update. Water from the Colorado River is considered to be most vulnerable to contamination from recreation, urban/stormwater runoff, increasing urbanization in the watershed, and wastewater.

Water supplies from Northern California’s State Water Project are most vulnerable to contamination from urban/stormwater runoff, wildlife, agriculture, recreation, and wastewater.

U.S. EPA also requires MWDSC to complete a source water assessment (SWA) that uses information collected in the watershed sanitary surveys. MWDSC completed its SWA in
December 2002. The SWA is used to evaluate the vulnerability of water sources to contamination and helps determine
whether more protective measures are needed. A copy of the most recent summary of the Watershed Sanitary Surveys or the SWA can be obtained by calling MWDSC at (800) CALLMWD (800-225-5693).

Groundwater Assessment
An assessment of the drinking water sources for the City was completed in December 2002. The groundwater sources are considered most vulnerable to the following activities not associated with detected contaminants: body shops,
chemical/petroleum processing/storage, electrical/electronic manufacturing, gas stations, historic gas stations, known contaminant plumes, machine shops, metal plating/finishing/ fabricating, photo processing/printing, repair shops, sewer collection systems, and wastewater treatment and disposal facilities. A copy of the complete assessment is available at State Water Resources Control Board, Division of Drinking Water, 2 MacArthur Place, Suite 150, Santa Ana, CA 92707. Further information and a summary of the assessments are available by contacting the City of La Palma at (714) 690-3310.

Sources of Supply
The City’s water supply is groundwater managed by the OCWD and treated surface water from Northern California and the Colorado River managed by the MWDSC.

OCWD’s groundwater comes from a natural underground
aquifer that is replenished with water from the Santa Ana River, local rainfall, and imported water. The groundwater basin is 350 square miles and lies beneath north and central Orange County from Irvine to the Los Angeles County border and from Yorba Linda to the Pacific Ocean. More than 20 cities and retail water districts draw from the basin to provide water to homes and businesses.

Your Water Quality Report
Since 1990, California public water utilities have been providing an annual Water Quality Report, also known as the Consumer Confidence Report, to their customers. This year’s report covers drinking water quality testing and reporting for 2025. Your City of La Palma Community Development & Public Works Department vigilantly safeguards its water supply, and as in years past, the water delivered to your home meets the quality standards required by federal and state regulatory agencies. The U.S. Environmental Protection Agency (U.S. EPA) and the State Water Resources Control Board (SWRCB), Division of Drinking Water (DDW) are the agencies responsible for establishing and enforcing drinking water quality standards.

In some cases, the City goes beyond what is required by testing for unregulated chemicals that may have known health risks but do not have drinking water standards. For example, the Orange County Water District (OCWD), which manages the groundwater basin, tests for unregulated chemicals in our water supply. Unregulated chemical monitoring helps U.S. EPA and DDW determine where certain chemicals occur and whether new standards need to be established for those chemicals to protect public health.

Through drinking water quality testing programs carried out by OCWD for groundwater, the Metropolitan Water District of Southern California (MWDSC) for treated surface water, and the City for the water distribution system, your drinking water is constantly monitored from source to tap for regulated and unregulated contaminants. The state allows the City to monitor for some contaminants less than once per year because the concentrations of these contaminants do not change frequently. Some of our data, though representative, is more than a year old.

Important Health Information
Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health-care providers. U.S. EPA/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline (1-800-426-4791).

We Invite You to Learn More About
Your Water’s Quality
For information about this report, or your water quality in general, please contact the Community Development & Public Works Department at (714) 690-
3310. For more information about the health effects of the listed contaminants in the following tables, call the U.S.

EPA hotline at (800) 426-4791. The city council meets on the first Tuesday of every month at 6:30 p.m. in the City Council Chambers, located at 7822 Walker Street. Please feel free to participate in these meetings.

Quality Water is Our Priority
Turn the tap and the water flows, as if by magic. Or so it seems. The reality is considerably different. Delivering high-quality drinking water to our customers is a scientific and engineering feat that requires considerable effort and talent to ensure
the water is always there, always safe to
drink. Because tap water is highly regulated by state and federal laws, water treatment and distribution operators must be licensed.

Our licensed water professionals have an understanding of a wide range of subjects, including mathematics, biology, chemistry, physics, and engineering. Some of the tasks they complete on a regular basis include:
• Operating and maintaining equipment to purify and
clarify water;
• Monitoring and inspecting machinery, meters, gauges,
and operating conditions;
• Conducting tests and inspections on water and
evaluating the results;
• Documenting and reporting test results and system
operations to regulatory agencies; and
• Serving our community through customer support,
education, and outreach.

So the next time you turn on your faucet, think of the skilled professionals who stand behind every drop.

About Lead in Tap Water
Lead can cause serious health problems, especially for pregnant women and young children. Lead
in drinking water is primarily from
materials and components associated
with service lines and home plumbing. The City of La Palma is responsible for providing high quality drinking water and removing lead pipes, but cannot control the variety of materials used in plumbing components in your home. You share the responsibility for protecting yourself and your family from the lead in your home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and taking steps to reduce your family’s risk. Before drinking tap water, flush your pipes for several minutes by running your tap, taking a shower, doing laundry or a load of dishes. You can also use a filter certified by an American National Standards Institute accredited certifier to reduce lead in drinking water. If you are concerned about lead in your water and wish to have your water tested, contact the City of La Palma Community Development & Public Works Department at http://www.
epa.gov/safewater/lead.

Orange County’s Water Future
For years, Orange County has enjoyed an abundant
and seemingly endless supply of high-quality water.

As water demand continues
to increase statewide, we
must be even more conscientious about our water supply and maximize the efficient
use of this precious natural resource. OCWD and the Municipal Water District of Orange County (MWDOC) work cooperatively to evaluate
new and innovative water management and supply development programs, including water reuse and recycling, wetlands expansion, recharge facility construction, ocean and brackish water desalination, surface storage, and water use efficiency programs. These efforts are helping to enhance long-term countywide water reliability and water quality.

A healthy water future for Orange County rests on finding and developing new water supplies, as well as protecting and improving the quality of the water that we have today. Your local and regional water agencies are committed to making the necessary investments in new water management projects today to ensure an abundant and high-quality water supply for our future.

Arsenic
While your drinking water meets the federal and state standard for arsenic, it does contain low levels of arsenic. The arsenic standard balances the current understanding of arsenic’s possible health effects against the costs of removing arsenic from drinking water. The U.S. EPA continues to research the health effects of low levels of arsenic, which is a mineral known to cause cancer in humans at high concentrations and linked to other health effects such as skin damage and circulatory problems.

Lead Service Line Inventory
La Palma has completed the lead service line initial inventory (LSLI) required by U.S. EPA’s Lead and Copper Rule Revisions. The deadline for the LSLI was October 16, 2024.

Through completing a historical records review and field investigations, the City has determined that all service lines within the distribution system are lead-free. This includes all customer-owned service lines. For more information, please contact the Community Development & Public Works
Department at (714) 690-3310.

LEAD AND COPPER ACTION LEVELS AT RESIDENTIAL TAPS
2025 CITY OF LA PALMA DISTRIBUTION SYSTEM WATER QUALITY

MCL (MRDL/
MRDLG)

AVERAGE
AMOUNT

RANGE OF

DETECTIONS
MCL

VIOLATION TYPICAL SOURCE OF CONTAMINANT
Disinfection Byproducts
Total Trihalomethanes (ppb) 80 16 4 - 18 No Byproducts of chlorine disinfection Haloacetic Acids (ppb) 60 6 1.2 - 9.1 No Byproducts of chlorine disinfection Chlorine Residual (ppm) (4 / 4) 0.51 ND - 0.90 No Disinfectant added for treatment Aesthetic Quality
Color (color units) 15* 1 ND - 1 No Erosion of natural deposits Odor (threshold odor number) 3* 1 ND - 1 No Erosion of natural deposits Turbidity (ntu) 5* 0.74 ND - 4.48 No Erosion of natural deposits Eight locations in the distribution system are tested quarterly for total trihalomethanes and haloacetic acids; five locations are tested weekly for color, odor and turbidity. MRDL = Maximum Residual Disinfectant Level; MRDLG = Maximum Residual Disinfectant Level Goal; *Contaminant is regulated by a secondary standard to maintain aesthetic qualities (taste, odor, color).

ACTION

LEVEL (AL)
PUBLIC
HEALTH
GOAL
90TH

PERCENTILE
VALUE

RANGE OF

DETECTIONS

SITES EXCEEDING AL
/ NUMBER OF SITES
AL
VIOLATION? TYPICAL SOURCE OF CONTAMINANT
Lead (ppb) 15 0.2 ND ND - 9.5 0 / 30 No Corrosion of household plumbing Copper (ppm) 1.3 0.3 0.17 ND - 0.41 0 / 30 No Corrosion of household plumbing 2025 City of La Palma Drinking Water Quality
For more information about the health effects of the listed contaminants in the following tables, call the U.S. EPA hotline at (800) 426-4791.

Thirty residences were tested for lead and copper at-the-tap during 2024. Lead was detected in 3 homes; none exceeded the regulatory Action Level (AL). Copper was detected in 20 homes; none exceeded the AL. A regulatory AL is the concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.

ppb = parts-per-billion; ppm = parts-per-million; pCi/L = picoCuries per liter; NTU = nephelometric turbidity units; µmho/cm = micromhos per centimeter; ND = not detected; NR = not required; MCL = Maximum Contaminant Level; (MCLG) = federal MCL Goal; PHG = California Public Health Goal; n/a = not applicable; * Contaminant is regulated by a secondary standard.
2025 CITY OF LA PALMA DRINKING WATER QUALITY LOCAL LOCAL GROUNDWATER AND METROPOLITAN WATER

DISTRICT (MWD) IMPORTED WATER

CHEMICAL MCL
PHG
(MCLG)

AVERAGE LOCAL

GROUNDWATER

AVERAGE MWD

SURFACE WATER

GROUNDWATER

RANGE OF

DETECTIONS
MCL
VIOLATION?

TYPICAL SOURCE OF

CONTAMINATION
Radiologicals - Tested in 2023, 2024, and 2025
Gross Alpha Particle
Activity (pCi/L)
15 (0) ND ND ND - 5 No Erosion of Natural Deposits
Gross Beta Particle
Activity (pCi/L)
50 (0) NR ND ND - 6 No Decay of Natural and Man-made
Deposits
Uranium (pCi/L) 20 0.43 ND 1 ND - 3 No Erosion of Natural Deposits Inorganic Chemicals - Tested in 2023 and 2025
Aluminum (ppm) 1 0.6 ND 0.058 ND - 0.082 No Treatment Process Residue, Natural Deposits
Arsenic (ppb) 10 0.004 6.8 ND ND - 9.3 No Erosion of Natural Deposits Barium (ppm) 1 2 ND 0.13 ND - 0.13 No Oil Drilling Waste and Metal Refinery Discharge; Erosion
Bromate (ppm) 10 0.1 NR 2.4 ND - 8.4 No Byproduct of Drinking Water Ozonation Fluoride (ppm) -
naturally-ocurring
2 1 0.44 NR 0.43 - 0.44 No Erosion of Natural Deposits
Fluoride (ppm)
treatment-related
2 1 NR 0.7 0.6 - 0.8 No Water Additive for Dental Health Secondary Standards* - Tested in 2023 and 2025
Aluminum (ppm) 200* 600 ND 58 ND - 82 No Treatment Process Residue, Natural Deposits
Chloride (ppm) 500* n/a 17 92 14 - 99 No Runoff or Leaching from Natural Deposits Color (color units) 15* n/a ND 1 ND - 1 No Naturally-occurring Organic Materials Manganese (ppb) 50* n/a 42 ND ND - 46 No Erosion of Natural Deposits Odor (threshold odor
number)
3* n/a ND ND ND - 1 No Naturally-occurring Organic Materials Specific
Conductance (µmho/
cm)
1,600* n/a 470 873 438 - 987 No Substances that Form Ions in Water Sulfate (ppm) 500* n/a 49.6 182 42.6 - 218 No Runoff or Leaching from Natural Deposits Total Dissolved
Solids (ppm)
1,000* n/a 294 545 270 - 625 No Runoff or Leaching from Natural Deposits Turbidity (ntu) 5* n/a 0.2 ND ND - 0.25 No Runoff or Leaching from Natural Deposits Unregulated Chemicals - Tested in 2023 and 2025
Alkalinity, total as
CaCO3 (ppm)
Not Regulated n/a 181 108 93 - 187 n/a Runoff or Leaching from Natural Deposits Calcium (ppm) Not Regulated n/a 42 56 41 - 68 n/a Runoff or Leaching from Natural Deposits Hardness, total
(ppm)
Not Regulated n/a 147 236 138 - 280 n/a Runoff or Leaching from Natural Deposits Hardness, total
(grains per gallon)
Not Regulated n/a 8.6 14 8.1 - 16 n/a Runoff or Leaching from Natural Deposits Magnesium (ppm) Not Regulated n/a 9.2 22 8 - 25 n/a Runoff or Leaching from Natural Deposits pH (pH unit) Not Regulated n/a 8 8.3 8 - 8.3 n/a Hydrogen Ion Concentration Potassium (ppm) Not Regulated n/a 2.1 4.3 2 - 4.8 n/a Runoff or Leaching from Natural Deposits Sodium (ppm) Not Regulated n/a 51 88 46 - 97 n/a Runoff or Leaching from Natural Deposits Total Organic
Carbon (ppm)
TT n/a ND 2.4 ND - 2.6 n/a Various Natural and Man-made Sources

METROPOLITAN WATER DISTRICT DIEMER

FILTRATION PLANT

TREATMENT

TECHNIQUE

TURBIDITY

MEASUREMENTS
TT
VIOLATION?

TYPICAL SOURCE IN DRINKING
WATER
Turbidity - combined filter effluent
1) Highest single turbidity measurement (NTU) 0.3 0.05 No Soil Runoff 2) Percentage of samples less than or equal to 0.3 NTU 95% 100% No Soil Runoff Turbidity is a measure of the cloudiness of the water, an indication of particulate matter, some of which might include harmful microorganisms. Low turbidity in Serrano Water District’s treated water is a good indicator of effective filtration. Filtration is called a “treatment technique”. A treatment technique is a required process intended to reduce the level of contaminants in drinking water that are difficult and sometimes impossible to measure directly. NTU = nephelometric turbidity units

UNREGULATED CHEMICALS REQUIRING MONITORING

CHEMICAL

NOTIFICATION

LEVEL PHG

AVERAGE

GROUNDWATER

AVERAGE

SURFACE WATER

RANGE OF

DETECTIONS MOST RECENT SAMPLING DATE
Lithium (ppb) Not Regulated n/a ND 22.4 ND - 36.7 2023

Drinking Water Contaminants
The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and
wells. As water travels over the surface of
the land or through the ground, it dissolves
naturally occurring minerals and, in some
cases, radioactive material and can pick up
substances resulting from the presence of
animals or from human activity.

Contaminants that may be present in source water include:
• Microbial contaminants, such as viruses and bacteria, that may come from sewage treatment plants, septic
systems, agricultural livestock operations, and wildlife. • Inorganic contaminants, such as salts and metals,
that can be naturally occurring or result from urban
stormwater runoff, industrial or domestic wastewater
discharges, oil and gas production, mining, or farming. • Pesticides and herbicides that may come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses.
• Organic chemical contaminants, including synthetic
and volatile organic chemicals, that are by-products of industrial processes and petroleum production and can
also come from gas stations, urban stormwater runoff,
agricultural application, and septic systems.
• Radioactive contaminants that can be naturally
occurring or the result of oil and gas production and
mining activities.

To ensure that tap water is safe to drink, the U.S. EPA and the SWRCB prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. U.S.

Food and Drug Administration regulations and California law also establish limits for contaminants in bottled water that provide the same protection for public health.

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some
contaminants. The presence of contaminants does not
necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the U.S. EPA’s Safe Drinking Water Hotline (1-800-426-4791).

Drinking Water Definitions
What are water quality standards?
Drinking water standards established by U.S. EPA and
DDW set limits for substances that may affect consumer
health or aesthetic qualities of drinking water.

The tables in this report show the following types of water quality standards:
• Maximum contaminant level (MCL): The highest
level of a contaminant that is allowed in drinking
water. Primary MCLs are set as close to the PHGs
(or MCLGs) as is economically and technologically
feasible.
• Maximum residual disinfectant level (MRDL):

The highest level of a disinfectant allowed in
drinking water. There is convincing evidence that
addition of a disinfectant is necessary for control of
microbial contaminants.
• Secondary MCLs are set to protect the odor, taste,
and appearance of drinking water.
• Primary drinking water standard (PDWS): MCLs
for contaminants that affect health, along with their
monitoring and reporting requirements and water
treatment requirements.
• Regulatory action level (AL): The concentration of
a contaminant that, if exceeded, triggers treatment or
other requirements that a water system must follow.

What is a water quality goal?
In addition to mandatory water quality standards, U.S.

EPA and DDW have set voluntary water quality goals
for some contaminants. Water quality goals are often
set at such low levels that they are not achievable in
practice and are not directly measurable. Nevertheless, these goals provide useful guideposts and direction for water management practices.

The tables in this report include three types of water
quality goals:
• Maximum contaminant level goal (MCLG): The
level of a contaminant in drinking water below
which there is no known or expected risk to health.

MCLGs are set by U.S. EPA.
• Maximum residual disinfectant level goal
(MRDLG): The level of a drinking water
disinfectant below which there is no known or
expected risk to health. MRDLGs do not reflect
the benefits of the use of disinfectants to control
microbial contaminants.
• Public health goal (PHG): The level of a
contaminant in drinking water below which there is
no known or expected risk to health. PHGs are set
by the California EPA.

How are contaminants measured?
Water is sampled and tested throughout the year.

Contaminants are measured in:
• Parts per million (ppm) or milligrams per liter
(mg/L)
• Parts per billion (ppb) or micrograms per liter (µg/L) • Parts per trillion (ppt) or nanograms per liter (ng/L) Cross Connections
I
n cooperation with the DDW, the City of La Palma’s major goal is to ensure the distribution of a safe potable water supply to all domestic water users. To achieve this goal, a CrossConnection Control Management Plan (CCCMP) is being developed with an effective date of July 1, 2025, pursuant to the requirements set forth in the Cross-Connection Control Policy Handbook (CCCPH), which replaced California
Administrative Code title 17, sections 7583 through 7605 and applies to all California public water systems, as defined in California’s Health and Safety Code (CHSC, section
116275(h)).

Disinfectants and Disinfection
By-Products in Drinking Water
Disinfection of drinking water was one of the greatest public health advancements of the 20th century, significantly reducing the spread of waterborne diseases caused by bacteria and viruses. Today chlorine and chloramines are commonly used disinfectants to ensure safe drinking water.

How Disinfection Works
• Chlorine is added at the water source (groundwater wells or treatment plants) to kill harmful microorganisms.
• Residual chlorine remains in the distribution system to prevent bacterial growth in the pipes that carry water to homes and businesses.
• Chloramines, a combination of chlorine and ammonia, are also used as a disinfectant and help reduce certain by-products.

Disinfection By-Products and Regulations
While effective, chlorine and chloramines can react with naturally occurring materials in water, forming disinfection by-products (DBPs), which may pose health risks. The most common DBPs are trihalomethanes (THMs) and haloacetic acids (HAAs).

To protect public health, the U.S. EPA regulates DBPs under the Safe Drinking Water Act:
• In 1979 the U.S. EPA set the maximum allowable total THM level at 100 parts per billion (ppb).
• In 2002 the Stage 1 Disinfectants/Disinfection Byproducts Rule lowered the limit to 80 ppb and added HAAs to the list of regulated chemicals.
• In 2006 the Stage 2 Disinfectants/Disinfection Byproducts Rule introduced further monitoring and control measures.
• Full compliance began in 2012.

Your drinking water meets or exceeds all state and federal standards, with rigorous monitoring in place. We regularly test for DBPs and adjust treatment methods to maintain a safe balance between disinfection and by-product control.

Important Considerations
• Fish and aquatic pets: Chloramines can be toxic to fish and should be removed from water used in aquariums.
• Kidney dialysis patients: Chloramines must be filtered from water used in dialysis treatment—consult your health-care provider.

For more information on water quality and regulations, visit:
• U.S. EPA water regulations: epa.gov/sdwa
• SWRCB: waterboards.ca.gov
Your drinking water is treated, tested, and monitored to ensure it remains safe and reliable for you and your community.

PFAS Advisory
Per- and polyfluoroalkyl substances (PFAS) are a group of human-made chemicals that have been used in various consumer products
since the 1940s due to their resistance to heat,
water, oils, and stains. These chemicals are prevalent in the environment and have been detected in water supplies nationwide. Studies suggest that
exposure to certain PFAS may pose health risks.

The U.S. EPA and the DDW have established
health-based advisories for PFAS. If PFAS levels exceed these guidelines, water agencies must notify their governing bodies and take necessary actions, such as removing affected sources from service or implementing treatment solutions.

To address PFAS contamination, water providers have
conducted testing and taken proactive steps to ensure safe drinking water.

Regulatory actions: The U.S. EPA announced final National Primary Drinking Water Regulations for six PFAS in April 2024. Public water systems are required to monitor these substances, with full compliance expected by 2029.

For more details on PFAS regulations and water safety, visit:
* California State Water Resources Control Board - Division of Drinking Water: waterboards.ca.gov/pfas
* Orange County Water District: ocwd.com/what-we-do/
water-quality/pfas
* U.S. EPA: epa.gov/pfas
City of La Palma Community Development
& Public Works Department
7822 Walker Street, La Palma, CA 90623
lapalmaca.gov/205/Water-Division
Drinking Water Fluoridation
Fluoride has been added to U.S. drinking water supplies since 1945 to help prevent tooth decay. As of today, the majority of public water suppliers in the country, including the MWDSC, fluoridate their water. MWDSC began adding
fluoride in December 2007, complying with all provisions of California’s fluoridation system requirements. Fluoride levels in drinking water are regulated in California and limited to a maximum of 2 parts per million (ppm). Some local groundwater supplies naturally contain fluoride, but they are not supplemented with additional fluoride.

Additional Information
For more details on water fluoridation, please visit:
• U.S. Centers for Disease Control and Prevention
(CDC): cdc.gov/fluoridation or (800) 232-4636
• State Water Resources Control Board, Division of
Drinking Water: waterboards.ca.gov/drinking_water/
certlic/drinkingwater/Fluoridation.html
• American Dental Association: ada.org
• American Water Works Association: awwa.org
For specific inquiries about MWDSC’s fluoridation program, please contact Edgar G. Dymally at (213) 217-5709 or [email protected].

Agenda Item No. 12 June 2, 2026 | 1
City of La Palma
Agenda Item No. 12
MEETING DATE: June 2, 2026
TO: City Council
FROM: City Manager
SUBMITTED BY: Jake Chavira, Acting Community Development & Public Works Director
AGENDA TITLE: Adoption of the 2025 Urban Water Management Plan and Water Shortage Contingency Plan
RECOMMENDED ACTION:

It is recommended that the City Council take the following actions:

1. Open Public Hearing

2. Receive Staff Report

3. Council Comments and Questions

4. Receive Public Input

5. Close Public Hearing

6. Adopt the 2025 Urban Water Management Plan and the Water Shortage Contingency Plan.

BACKGROUND:

As required under California Water Code Section 10621, the City of La Palma is required to update its Urban Water Management Plan (UWMP) and Water Shortage Contingency Plan (WSCP) every five years. The last UWMP for La Palma was prepared and submitted in 2021. The Department of Water Resources (DWR) requires that all 2025 UWMP’s be submitted by July 1, 2026.

SUMMARY:
2025 Urban Water Management Plan
UWMPs are comprehensive documents that present an evaluation of a water supplier’s reliability over a long-term (20-25 year) horizon. In response to the changing climatic conditions and regulatory updates since the 2015 UWMP, the City has been proactively managing its water supply and demand.

The water loss audit program, water conservation measures, and efforts to increase self-reliance to reduce dependence on imported water from the Sacramento-San Joaquin Delta (the Delta) are among the water management efforts the City participates in to maintain the reliability of its water supply. The

Agenda Item No. 12 June 2, 2026 | 2
2025 UWMP provides an assessment of the present and future water supply sources and demands within the City’s service area. It also updates the City’s 2020 UWMP regarding water resource needs, water use efficiency programs, water reliability assessment, and strategies to mitigate water shortage conditions.
2025 Water Shortage Contingency Plan
WSCPs are strategic planning documents designed to prepare for, respond to, and reduce the impacts of water shortages or supply interruptions. The City’s WSCP complies with California Water Code Section 10632, requiring every urban water supplier to prepare and adopt a WSCP as part of its UWMP.

The City’s WSCP will be used as a proactive operating manual to prevent catastrophic service disruptions. This plan provides a structured guide for the City to address water shortages, incorporating prescriptive information and standardized action levels, as well as implementation actions in the event of a catastrophic supply interruption. If and when shortage conditions arise, the City Council, staff, and the public can easily identify and efficiently implement predetermined steps to manage a water shortage. The WSCP enables real-time assessment of water supply availability and structured steps designed to respond to actual conditions, allowing for efficient management of any shortage.

The WSCP also outlines the City’s procedures for conducting an Annual Water Supply and Demand Assessment (Annual Assessment), as required by California Water Code Section 10632.1. This Annual Assessment is to be submitted to the California DWR on or before July 1 of each year, or within 14 days of receiving final allocations from the State Water Project (SWP), whichever is later.

The City’s 2025 WSCP is included as an appendix to its 2025 UWMP, which will be submitted to DWR by July 1, 2026.

FISCAL IMPACT:

Funding has been appropriated in the FY 2025-26 CIP Budget (055-900-9150-00000) for the planning, design, and preparation of the Urban Water Management Plan and Water Shortage Contingency Plan.

ATTACHMENTS:

1. La Palma 2025 Urban Water Management Plan

2. La Palma 2025 Water Shortage Contingency Plan

2025 Urban Water
Management Plan
FINAL DRAFT / May 2026
in collaboration with and

2025 Urban Water Management Plan
May 2026 / FINAL DRAFT
Prepared By: Prepared For:

Carollo Engineers, Inc. City of La Palma
707 Wilshire Boulevard, Suite 3920 7281 Walker Street
Los Angeles, California 90017 La Palma, California 90623 Phone: 213.489.1587 Phone: 714.690.3310
https://www.carollo.com https://www.cityoflapalma.org
In collaboration with:

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pw://Carollo/CA/MWDOC/204447-000000/03 Reports and Studies/02 Deliverables/Grp1_La Palma UWMP/_Cover_TOC_Abbrevs_AppxCovers.docx Contents

EXECUTIVE SUMMARY
ES.1 Introduction and UWMP Overview ES-1
ES.2 UWMP Preparation ES-1
ES.3 System Description ES-1
ES.4 Water Use Characterization ES-1
ES.4.1 Water Use in the Last Five Years ES-1
ES.4.2 Projected Water Use ES-2
ES.5 Conservation Target Compliance ES-2
ES.6 Water Supply Characterization ES-2
ES.7 Water Service Reliability and Drought Risk Assessment ES-2 ES.8 Water Shortage Contingency Planning ES-3
ES.9 Demand Management Measures ES-3
ES.10 Plan Adoption, Submittal, and Implementation ES-3 CHAPTER 1 INTRODUCTION AND UWMP OVERVIEW

1.1 Overview of UWMP Requirements 1-1

1.2 UWMP Organization 1-2
CHAPTER 2 UWMP PREPARATION

2.1 Individual Planning and Compliance 2-2

2.2 Coordination and Outreach 2-3

2.2.1 Integration with Other Planning Efforts 2-3

2.2.2 Wholesale and Retail Coordination 2-5

2.2.3 Public Participation 2-5
CHAPTER 3 SYSTEM DESCRIPTION

3.1 Agency Overview 3-1

3.1.1 Formation and Purpose 3-1

3.1.2 City Council 3-2

3.1.3 Relationship to MWDOC 3-2

3.2 Water Service Area and Facilities 3-4

3.2.1 Water Service Area 3-4

3.2.2 Water Facilities 3-5

3.3 Climate 3-5

3.4 Population, Demographics, and Socioeconomics 3-6

3.4.1 Service Area Population 3-6

3.4.2 Demographics and Socioeconomics 3-6

3.4.3 Demographic Projection Methodology 3-6

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3.5 Land Uses 3-7

3.5.1 Current Land Uses 3-7

3.5.2 Projected Land Uses 3-7
CHAPTER 4 WATER USE CHARACTERIZATION

4.1 Water Use in the Last Five Years 4-4

4.2 Projected Water Use 4-5

4.2.1 Water Use Projections for 2026-2030 4-5

4.2.2 Water Use Projections for 2030-2050 4-5

4.3 Water Demand Projection Methodology 4-7

4.3.1 Econometric Approach, Data Acquisition, and Model Development 4-8

4.3.2 Forecasted Demands 4-10

4.4 Water Loss 4-11
CHAPTER 5 CONSERVATION TARGET COMPLIANCE

5.1 Reporting Requirements 5-1
CHAPTER 6 WATER SUPPLY CHARACTERIZATION

6.1 Water Supply Overview 6-1

6.2 Imported Water 6-5

6.2.1 Metropolitan Water District of Southern California 6-5

6.2.2 Colorado River Aqueduct 6-8

6.2.3 State Water Project 6-11

6.2.4 Storage, Transfers, and Conveyance Programs 6-14

6.2.5 Potential Future Water Projects 6-16

6.2.6 Supply Reliability Within MET 6-17

6.3 Local Groundwater 6-22

6.3.1 Orange County Groundwater Basin 6-22

6.3.2 Planned Future Groundwater Sources 6-30

6.4 Surface Water 6-31

6.4.1 Existing Surface Water Sources 6-31

6.4.2 Planned Future Surface Water Sources 6-31

6.5 Stormwater 6-31

6.5.1 Existing Stormwater Sources 6-31

6.5.2 Planned Future Stormwater Sources 6-31

6.6 Wastewater and Recycled Water 6-31

6.6.1 Agency Coordination 6-31

6.6.2 Wastewater 6-33

6.6.3 Current Recycled Water Uses 6-34

6.6.4 Projected Recycled Water Uses 6-34

6.6.5 Potential Recycled Water Uses 6-34

6.6.6 Optimization Plan 6-34

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6.7 Desalination Opportunities 6-35

6.7.1 Ocean Water Desalination 6-35

6.7.2 Groundwater Desalination 6-35

6.8 Water Exchanges and Transfers 6-36

6.8.1 Existing Exchanges and Transfers 6-36

6.8.2 Planned and Potential Exchanges and Transfers 6-36

6.9 Future Water Projects 6-37

6.10 Energy Intensity 6-37
CHAPTER 7 WATER SERVICE RELIABILITY AND DROUGHT RISK

ASSESSMENT

7.1 Water Service Reliability Overview 7-1

7.2 Factors Affecting Water Supply Reliability 7-2

7.2.1 Climate Change and the Environment 7-2

7.2.2 Regulatory and Legal 7-3

7.2.3 Water Quality 7-4

7.2.4 Locally Applicable Criteria 7-7

7.3 Water Service Reliability Assessment 7-8

7.3.1 Normal Year Reliability 7-8

7.3.2 Single Dry Year Reliability 7-8

7.3.3 Multiple Dry Years Reliability 7-9

7.4 Management Tools and Options 7-10

7.4.1 Methodology 7-12

7.4.2 Water Source Reliability 7-14
CHAPTER 8 WATER SHORTAGE CONTINGENCY PLANNING

8.1 Background 8-1

8.2 Overview of the Water Shortage Contingency Plan 8-1

8.3 Summary of Water Shortage Response Strategy and Required DWR Tables 8-2 CHAPTER 9 DEMAND MANAGEMENT MEASURES

9.1 City of La Palma Demand Management Measures 9-2

9.1.1 Operations Practices 9-3

9.1.2 Public Education and Outreach 9-6

9.1.3 Residential Indoor Rebate Programs 9-7

9.1.4 CII Programs 9-8

9.1.5 Landscape Programs 9-9

9.2 City of La Palma DMM Implementation (2020-2025) 9-10

9.3 MWDOC Demand Management Implementation Assistance Programs 9-10

9.3.1 State Water Conservation Compliance Assistance 9-11

9.3.2 Regional Rebate Programs and Local Program Assistance 9-12

9.3.3 Research and Evaluation 9-12

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9.4 Urban Water Use Objective and CII Performance Measure Compliance 9-13

9.4.1 UWUO Components 9-13

9.4.2 CII Performance Measures 9-14
CHAPTER 10 PLAN ADOPTION, SUBMITTAL, AND IMPLEMENTATION

10.1 Overview 10-1

10.2 Agency Coordination 10-2

10.3 Public Participation 10-3

10.4 UWMP Submittal 10-3

10.5 Amending the Adopted UWMP or WSCP 10-3
CHAPTER 11 REFERENCES
Appendices

APPENDIX A UWMP WATER CODE CHECKLIST

APPENDIX B DEPARTMENT OF WATER RESOURCES (DWR) STANDARDIZED TABLES

APPENDIX C REDUCED DELTA RELIANCE

APPENDIX D AWWA WATER LOSS AUDITS
APPENDIX E 2022 BASIN 8-1 ALTERNATIVE UPDATE

APPENDIX F WATER SHORTAGE CONTINGENCY PLAN

APPENDIX G WATER USE EFFICIENCY IMPLEMENTATION REPORT
APPENDIX H 2025 ORANGE COUNTY WATER DEMAND MODEL TECHNICAL MEMORANDUM

APPENDIX I NOTIFICATION OF PUBLIC AND SERVICE AREA PROVIDERS

APPENDIX J ADOPTED UWMP RESOLUTIONS
Tables
Table 2.1 Submittal Table 2-1 Retail: Public Water Systems 2-2 Table 2.2 Submittal Table 2-2: Plan Identification 2-2
Table 2.3 Submittal Table 2-3: Supplier Identification 2-3 Table 2.4 Submittal Table 2-4 Retail: Water Supplier Information Exchange 2-5 Table 3.1 Submittal 3-1 Retail: Population - Current and Projected 3-6 Table 3.2 City’s Service Area Dwelling Units by Type 3-6 Table 4.1 Submittal Table 4-1 Retail: Total Uses for Potable and Non-Potable Water – Actual 4-4
Table 4.2 City of La Palma’s Service Area Total Potable for 2026-2030 4-5 Table 4.3 Submittal Table 4-2 Retail: Total Uses of Potable, and Non-Potable Water - Projected 4-6
Table 4.4 Submittal Table 4-3 Retail: Inclusion in Water Use Projections 4-6 Table 4.5 Optional Submittal Table 4-4 Retail: Passive Water Savings Projections 4-7 Table 4.6 Summary of Demand Sectors 4-8
Table 4.7 Summary of Historical Data Collected for Model Development 4-9

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Table 4.8 Future Model Parameters 4-11
Table 4.9 Submittal Table 4-5 Retail: Water Loss Audit Reporting 4-12 Table 4.10 Submittal Table 4-6 Retail: Progress Towards 2028 Water Loss Standard 4-13 Table 5.1 Submittal Table 5-1 Retail: SB X7-7 2020 Target Progress 5-2 Table 6.1 Submittal Table 6-8 Retail: Water Supplies - 2025 Actual 6-2 Table 6.2 Submittal Table 6-9 Retail: Water Supplies - Projected 6-4 Table 6.3 MET SWP Program Capabilities 6-12
Table 6.4 MET's Projected Supply Capability and Demands through 2050 for a Normal Year 6-18
Table 6.5 MET's Projected Supply Capability and Demands through 2050 for a Single Dry Year 6-19
Table 6.6 MET's Projected Supply Capability and Demands through 2050 for a Drought (5 Consecutive Water Years) 6-20
Table 6.7 MET's Water Use, Supply, and Drought Risk Assessment for 2026-2030 6-21 Table 6.8 Submittal Table 6-1 Retail: Groundwater Pumped in the Past 5 Years Within the City's Service Area 6-22
Table 6.9 Management Actions Based on Changes in Groundwater Storage 6-27 Table 6.10 Submittal Table 6-2 Retail: Wastewater Collected within the City's Service Area in 2025 6-34
Table 7.1 Optional Submittal Table 7-1 Retail: Basis of Water Year Data (Reliability Assessment) 7-2
Table 7.2 Submittal Table 7-2 Retail: Normal Year Supply and Use Comparison 7-8 Table 7.3 Submittal Table 7-3 Retail: Single Dry Year Supply and Demand Comparison 7-9 Table 7.4 Submittal Table 7-4 Retail: Multiple Dry Years Supply and Demand Comparison 7-10
Table 7.5 Submittal Table 7-5 Retail: Five-Year Drought Risk Assessment 7-13 Table 8.1 Submittal Table 8-1: Cross-Reference for Standard vs Supplier Shortage Levels 8-3
Table 8.2 Submittal Table 8-2 Retail: Supply Augmentation and Other Actions 8-4 Table 8.3 Submittal Table 8-3 Retail: Demand Reduction Actions 8-5 Table 9.1 DMM Implementation Responsibility and Regional Programs in Orange County 9-2
Table 9.2 City of La Palma Water Use Efficiency Program Participation 9-10 Table 9.3 MWDOC Programs to Help OC Retail Agencies Meet their Urban Water Use Objectives 9-13
Table 9.4 City of La Palma CII BMP and Water Efficiency Programs and Incentives 9-15 Table 10.1 External Coordination and Outreach 10-1
Table 10.2 Submittal Table 10-1 Retail: Notification to Cities and Counties 10-2 Figures
Figure 3.1 Regional Location of the City of La Palma and Other MWDOC Member Agencies 3-3
Figure 3.2 City of La Palma Water Service Area 3-4
Figure 4.1 Historical Water Use and Population in Orange County 4-2

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Figure 4.2 Projected Water Use Across All Orange County Water Agencies 4-3 Figure 4.3 Econometric Demand Forecast Development Process 4-10 Figure 6.1 City's Projected Water Supply 6-3
Figure 6.2 Major Aqueducts that Supply Imported Water to Southern California (MET, 2025) 6-6
Figure 6.3 MET Feeders and Transmission Mains that Serve Orange County 6-7 Figure 6.4 Map of the OC Basin (OCWD, 2022 (Basin 8-1 Alternative 2022 Update)) 6-24 Figure 6.5 Basin 8-1 Management Areas (OCWD, 2023) 6-25 Figure 6.6 MWDOC Imported Water Sales for Groundwater Replenishment 6-30 Figure 8.1 Purpose and Relationships of the UWMP, WSCP, and Water Shortage Response Ordinance 8-1

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Abbreviations
AB Assembly Bill
ACS American Community Survey
ADU accessory dwelling units
AF acre-feet
AFY acre-feet per year
AMI Advanced Metering Infrastructure
AVEK Antelope Valley-East Kern
AWWA American Water Works Association
BEA Basin Equity Assessment
BiOps Biological Opinions
BMP best management practices
BPP Basin Production Percentage
BSA Boy Scouts of America
C Celsius
CAMP4W Climate Adaptation Master Plan for Water
Carollo Carollo Engineers
CDR Center for Demographic Research at California State University, Fullerton CEE Consortium for Energy Efficiency
CII Commercial, Industrial, and Institutional
City City of La Palma
Conservation Framework “Making California a Conservation Way of Life” Framework CPTP Coastal Pumping Transfer Program
CRA Colorado River Aqueduct
CRSS Colorado River Simulation System
CUP conjunctive use program
CUWCC California Urban Water Conservation Council
CWC California Water Code
CVP Central Valley Project
CY Calendar Year
DCP Drought Contingency Plan / Delta Conveyance Project DDW Division of Drinking Water
Delta Sacramento-San Joaquin Delta
DIM dedicated irrigation metersDOF State Department of Finance DRA Drought Risk Assessment
DMM Demand Management Measures
DVL Diamond Valley Lake

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DWR California Department of Water Resources
EIR Environmental Impact Report
EO Executive Order
EPA US Environmental Protection Agency
ESA Endangered Species Act
FIRO Forecast Informed Reservoir Operations
FY Fiscal Year
FMD flow monitoring device
GAC granular activated carbon
GIS geographic information system
gpcd gallons per capita per day
gpf gallons per flush
gpm gallons per minute
GAP Green Acres Project
GHG greenhouse gas
GIS geographic information system
GRP Groundwater Resilience Plan / Groundwater Reliability Plan GSA Groundwater Sustainability Agency
GSP Groundwater Sustainability Plan
GSWC Golden State Water Company
GWRS Groundwater Replenishment System
HCF hundred cubic feet
HDI hot-dry index
HECW high efficiency clothes washer
HET high efficiency toilet
HRL Healthy Rivers and Landscapes
ICS Intentionally Created Surplus
IRP Integrated Water Resources Plan
IRWD Irvine Ranch Water District
ITP Incidental Take Permit
IWCM Interim Water Control Manual
kWh kilowatt hour
LAM landscape area measurements
LDAP Landscape Design Rebate Program
LODES Longitudinal Employer-Household Dynamics
LRP Local Resources Program
LVL Leo J. Vander Lans Advanced Water Treatment Facility M&I municipal and industrial
MAF million acre-feet

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MCL maximum contaminant level
MET Metropolitan Water District of Southern California
MF microfiltration
MG million gallons
mgd million gallons per day
mg/L milligrams per liter
MUM mixed-use CII meters
MWDOC Municipal Water District of Orange County
MWDOC, 2025 2025 Orange County Water Demand Projection Model TM ND non-detect
NDMA N-nitrosodimethylamine
ng/L nanograms per liter
NPDES National Pollutant Discharge Elimination System
OC Basin Orange County Groundwater Basin
OC San Orange County Sanitation District
OCWD Orange County Water District
PFAS per- and polyfluoroalkyl substances
PPCP pharmaceuticals and personal care products
ppt parts per trillion
PRISM Parameter Elevation Regressions on Independent Slopes Model PRS pressure regulating stations
QSA Quantification Settlement Agreement
QWEL Qualified Water Efficient Landscaper
R&I retail and municipal
RA Replenishment Assessment
RHNA Regional Housing Needs Assessment
RO reverse osmosis
SARCCUP Santa Ana River Conservation and Conjunctive Use Program SB Senate Bill
SCAB South Coast Air Basin
SCADA supervisory control and data acquisition
SCAG Southern California Association of Governments
SDCWA San Diego County Water Authority
SDW Single Family Dwelling
SGMA Sustainable Groundwater Management Act
SNWA Sierra Nevada Water Authority
sq mi square mile
SR 22 Garden Grove Freeway
SR 57 Orange County Freeway

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State State of California
STEM science, technology, engineering, and mathematics
Supplier urban water supplier
SWP State Water Project
SWRCB State Water Resources Control Board
TAZ traffic analysis zones
TAP Conservation Framework Technical Assistance Program TDS total dissolved solids
TM technical memorandum
USACE US Army Corps of Engineers
USBR United States Bureau of Reclamation
USGS United States Geological Survey
UV ultraviolet
UWMP Urban Water Management Plan
UWMP Act or Act UWMP Act of 1983
UWUO Urban Water Use Objective
Valley San Bernardino Valley Municipal Water District
Water Code California Water Code
WCM Water Control Manual
WEEA Water Energy Education Alliance
WRD Water Replenishment District
WR P1 Delta Stewardship Council’s Delta Plan Policy WR P1 WSAP Water Supply Allocation Plan / Water Savings Action Plan WSIP Water Savings Incentive Program
WSCP Water Shortage Contingency Plan
WUE Water Use Efficiency

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EXECUTIVE SUMMARY
ES.1 Introduction and UWMP Overview
The City of La Palma (City) prepared this 2025 Urban Water Management Plan (UWMP) to submit to the California Department of Water Resources (DWR) to satisfy the UWMP Act of 1983 (UWMP Act or Act) and subsequent California Water Code (Water Code) requirements. UWMPs are comprehensive documents that present an evaluation of a water supplier’s reliability over a long-term (20-25 year) horizon. This 2025 UWMP provides an assessment of the present and future water supply sources and demands within the City’s service area. It presents an update to the 2020 UWMP on the City’s water resource needs, water use efficiency programs, water reliability assessment, and strategies to mitigate water shortage conditions. It also presents the City’s updated 2025 Water Shortage Contingency Plan (WSCP), designed to prepare for and respond to water shortages. This 2025 UWMP contains all elements required by the UWMP Act.

ES.2 UWMP Preparation
The City coordinated the preparation of this 2025 UWMP with other key entities, the Municipal Water District of Orange County (MWDOC), the regional wholesaler of imported water for Orange County, and the Orange County Water District (OCWD), Orange County Groundwater Basin (OC Basin) manager and provider of recycled water in north Orange County. The City also coordinated with other entities that provided valuable, regionally consistent data for the analyses prepared in this UWMP, including population projections from the Center for Demographic Research (CDR) at California State University, Fullerton, and the Orange County Water Demand Projection Model Technical Memorandum (TM).

ES.3 System Description
The City was incorporated in October 1955 and lies in north Orange County at the border of Los Angeles County and is bounded by the City of Cerritos on the north and west, the City of Buena Park on the east, and the City of Cypress on the south. The City serves water within its city limits and to a portion of the City of Cerritos. The City operates two groundwater wells, two reservoirs with a total capacity of 4.5 million gallons (MGs), and manages a 39.7-mile water mains system with approximately 4,372 service connections.

ES.4 Water Use Characterization
ES.4.1 Water Use in the Last Five Years
Total water use within the City’s service area has fluctuated over the past five years (fiscal year [FY] 2021-25), with an annual average of approximately 1,741 acre-feet (AF). FY 2020-21 through FY 2021-22 saw the highest water use over the last five years due to region-wide drought conditions. FY 2022-23 proved to be one of the wettest years on record in the State and the City saw a general decrease in water demand following this wet year, as precipitation offsets landscape irrigation demands. These year-to-year

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fluctuations in precipitation will continue to influence the City’s annual demands. In general, the City saw a decrease in demand of 16 percent over the 5-year reporting period.

ES.4.2 Projected Water Use
The water use projection for this UWMP is based on the 2025 Orange County Water Demand Projection Model Technical Memorandum (TM). This demand projection represents the City’s total water demand and considers factors such as weather, water price, regional economic conditions, and housing density through a regression, or econometric, model.

Over the next 25 years, the City’s total water demands are projected to increase by about 3 percent from 1,670 AF in 2025 to approximately 1,721 AF by 2050. The Orange County Groundwater Basin is expected to continue meeting a notable share of total water demand between 2025 and 2050 (with a Basin Pumping Percentage [BPP] of 85 percent forecasted through 2050).

ES.5 Conservation Target Compliance
The City participated in the Orange County 20x2020 Regional Alliance along with all other Orange County water agencies. The alliance was created by MWDOC in collaboration with all its retail member agencies as well as the Cities of Anaheim, Fullerton, and Santa Ana, to assist Orange County retail agencies in complying with the requirements of the Water Conservation Act of 2009, also known as SBx7-7 (Senate Bill 7 as part of the Seventh Extraordinary Session). Signed into law on February 3, 2010, it required the State of California to reduce urban water use by 20 percent by 2020.

Retail water suppliers are required to comply with SBx7-7 individually or as a region in collaboration with other retail water suppliers, to be eligible for water-related state grants and loans. Orange County, as a region, achieved its 2020 target water use of 159 gallons per capita per day (GPCD) prior to 2020, indicative of the collective efforts in reducing water use in the region. All Orange County water retailers, achieved individual compliance prior to 2020. By 2020, the City achieved a per capita per day water use of 75 GPCD (compared to its 129 GPCD target) and continues to implement water use efficiency measures.

ES.6 Water Supply Characterization
The City’s main source of water supply is groundwater from the OC Basin. Imported water makes up the rest of the City’s water supply portfolio. In FY 2024-25, the City relied on approximately 97 percent groundwater and 3 percent imported water. This supply portfolio is projected to remain stable for the next 25 years with the BPP of 85 percent forecasted through 2050.

ES.7 Water Service Reliability and Drought Risk Assessment Every urban water supplier is required to assess the reliability of their water service to its customers under a normal year, a single dry year, and multiple dry years. The water service reliability assessment compares projected supply to projected demand for three long-term hydrological conditions. The City’s water sources are local groundwater from the OC Basin and imported water purchased from MWDOC/MET.

The OC Basin manager, OCWD, has developed programs and projects to improve groundwater recharge and augment groundwater through recycled water, conjunctive use, and water transfers. OCWD assesses groundwater conditions and sets its BPP, which determines how much water will be pumped from the

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basin year, and the Basin Equity Assessment (BEA), which is a surcharge for exceeding the BPP. The BPP is set at 85 percent and is forecasted to remain so through 2050.

MET, the Southern California regional wholesaler of imported water, has also invested in numerous programs and projects to augment its direct deliveries of imported water, such as water transfers, groundwater banking, and use of its reservoir storage. MET’s 2025 UWMP demonstrates that MET will be able to meet its projected water demands for its entire service area for the next 25 years under normal, dry, and five consecutive dry year conditions.

Overall, the City’s service area is projected to meet full-service demands from 2026 through 2050 under normal years, single dry year, and five consecutive dry year conditions.

ES.8 Water Shortage Contingency Planning
The Water Shortage Contingency Plan (WSCP) is a standalone document adopted by the City serving as the guidance document used to prepare for and respond to water shortages and service disruptions of the City’s water supplies through proactive mitigation measures. A water shortage, when water supply available is insufficient to meet the normally expected customer water use at a given point in time, may occur due to a number of reasons, such as water supply quality changes, climate change, drought, and catastrophic events (e.g., earthquake). The City’s WSCP provides a water supply availability assessment and structured steps designed to respond to actual conditions. This level of detailed planning and preparation will help maintain reliable supplies and reduce the impacts of supply interruptions.

The WSCP contains the processes and procedures that will be deployed when shortage conditions arise so that the City’s governing body and its staff can easily identify and efficiently implement pre-determined steps to mitigate a water shortage to the level appropriate to the degree of water shortfall anticipated.

ES.9 Demand Management Measures
The City has demonstrated its commitment to water use efficiency through multi-faceted and holistic water use efficiency programs. The City’s water use efficiency implementation can be described broadly under five categories: Operations Practices (e.g., conservation pricing, water waste prevention, water loss control, and metering with commodity rates), Education and Outreach (e.g., public outreach programs, K12 school programs, Water Awareness Poster Contest, Qualified Water Efficiency Landscaper Training Program), Residential Indoor Program (e.g. various rebates), Commercial, Industrial, and Institutional Program (e.g., rebates, Water Savings Incentive Program, On-site Retrofit Program), and Landscape Programs (e.g., turf replacement, spray-to-drip irrigation rebate, residential landscape design assistance).

ES.10 Plan Adoption, Submittal, and Implementation
The Water Code requires both the UWMP and the WSCP to be adopted by the Supplier’s governing body.

Before the adoption of the UWMP, the City notified the public and the cities and counties within its service area that MWDOC was in the process of preparing an UWMP and WSCP per the Water Code. The City circulated the final draft of the UWMP and WSCP to facilitate public review and held a public hearing to receive input from the public on the UWMP and WSCP. Upon completion of the public hearing, the City moved to adopt both the UWMP and WSCP. Post adoption, the City submitted the UWMP to DWR and other key agencies and made the document available for public review within 30 days after filing with DWR.

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The UWMP serves as a legal and technical water management foundation for the City and can be referenced as needed, until its next required update cycle in 2030. With approval from DWR, the City shall implement this plan into its public resources, providing City staff, the public, and elected officials with an understanding of past, current, and future water conditions and management. Furthermore, the WSCP serves as a strategic planning document designed to prepare for and respond to water shortages and service disruptions of the City’s water supplies.

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CHAPTER 1 INTRODUCTION AND UWMP OVERVIEW
The City of La Palma (City) prepared this 2025 Urban Water Management Plan (UWMP) to submit to the California Department of Water Resources (DWR) to satisfy the UWMP Act of 1983 (UWMP Act or Act) and subsequent California Water Code (Water Code) requirements.

The City is a retail water supplier that provides water to its residents and other customers using the imported potable water supply obtained from its regional wholesaler, Municipal Water District of Orange County (MWDOC) and local groundwater from the Orange County Groundwater Basin (OC Basin), which is managed by the Orange County Water District (OCWD). The City, as one of MWDOC’s 27 member agencies, prepared this 2025 UWMP in collaboration with MWDOC, Metropolitan Water District of Southern California (MET), OCWD, and other key agencies.

UWMPs are comprehensive documents that present an evaluation of a water supplier’s reliability over a long-term (20 to 25 year) horizon. In response to the changing climatic conditions since the 2020 UWMP, MWDOC has been assisting its member agencies and surrounding communities to manage both their water supplies and demands. The water loss audit program, water conservation measures, public outreach and education on conservation and efforts for increased self-reliance to reduce dependency on imported water from the Sacramento-San Joaquin Delta (the “Delta”) are some of the water management actions that the City has taken to maintain the reliability of water supply for its service area. In addition, the City has been proactive in managing local water supplies impacted by groundwater quality through the rehabilitation of current wells and exploring water treatment systems since 2020. Lastly, the City has been in close communication with neighboring agencies to maintain and develop strategic pipeline interties and retrofitting emergency inter-connections for emergency use.

This UWMP provides an assessment of the present and future water supply sources and demands within the City’s service area. It presents an update to the 2020 UWMP on the City’s water resource needs, water use efficiency programs, water reliability assessment and strategies to mitigate water shortage conditions.

It also includes the City’s updated 2025 Water Shortage Contingency Plan (WSCP) designed to prepare for and respond to water shortages. This 2025 UWMP contains all elements required by the Act.

1.1 Overview of UWMP Requirements
The UWMP Act enacted by California legislature requires every urban water supplier (Supplier) providing water for municipal purposes to more than 3,000 customers or supplying more than 3,000 acre-feet (AF) of water annually to prepare, adopt, and file an UWMP with the DWR every five years in the years ending in six and one.

For this 2025 UWMP cycle, DWR continues to place emphasis on achieving improvements for long term reliability and resilience to drought and climate change in California. Despite there being no new statutory requirements, Suppliers must now report progress on meeting their 2028 Water Loss Standards and continue to state their compliance with Senate Bill (SB) X7-7 2020 Targets. Additional guidance on stored water accounting and recommendations on identifying the need for future or proposed water supply projects are provided by DWR as well.

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1.2 UWMP Organization
This UWMP is organized into 10 chapters aligned with the DWR Guidebook recommendations.

The sections within each chapter are customized to include the City’s water supply reliability and future projections as well as plans to overcome any water shortages over a planning horizon of the next 25 years. The chapters for this UWMP are listed below:

Chapter 1 Introduction and UWMP Overview gives an overview of the UWMP fundamentals and requirements for the 2025 UWMP.

Chapter 2 UWMP Preparation identifies this UWMP as an individual planning effort of the City, lists the type of year and units of measure used and introduces the coordination and outreach activities conducted by the City to develop this UWMP.

Chapter 3 System Description gives a background on the City’s water system and its climate characteristics, population projections, demographics, socioeconomics, and predominant current and projected land uses of its service area.

Chapter 4 Water Use Characterization provides historical, current, and projected water use by customer category for the next 25 years for the City and the projection methodology used by the City to develop the 25-year projections.

Chapter 5 Conservation Target Compliance restates that the City’s 2020 per capita water use in gallons per capita per day (gpcd) met the compliance target defined by SB X7-7.

Chapter 6 Water Supply Characterization describes the current water supply portfolio of the City as well as the planned and potential water supply projects and water exchange and transfer opportunities.

Chapter 7 Water Service Reliability and Drought Risk Assessment describes the assessment of the reliability of the City’s water supply service to its customers for a normal year, single dry year and five consecutive dry years scenarios. This section also includes a Drought Risk Assessment (DRA) of all the supply sources for a consecutive five-year drought period beginning 2026.

Chapter 8 Water Shortage Contingency Planning is a brief summary of the standalone WSCP document which provides a structured guide for the City to deal with water shortages, incorporating prescriptive information and standardized action levels, lists the appropriate actions and water use efficiency measures to be taken to ensure water supply reliability in times of water shortage conditions, along with implementation actions in the event of a catastrophic supply interruption.

Chapter 9 Demand Management Measures provides a description of the City’s current and planned measures and programs to help the retail customers in its service area be water efficient and comply with the City’s urban water use reduction targets.

Chapter 10 Plan Adoption, Submittal, and Implementation provides a record of the process the City followed to adopt and implement its UWMP.

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CHAPTER 2 UWMP PREPARATION
The City of La Palma’s (City) 2025 Urban Water Management Plan (UWMP) is prepared to meet the California Water Code (Water Code) compliance as a retail water supplier to its customers. The development of this UWMP involved close coordination with its wholesale supplier, the Municipal Water District of Orange County (MWDOC), along with other key entities within the region.

2.1 Individual Planning and Compliance
As described in Chapter 1, every urban water supplier providing water for municipal purposes to more than 3,000 customers or supplying more than 3,000 acre-feet (AF) of water annually must prepare, adopt, and file an UWMP with the California Department of Water Resources (DWR) every five years to meet the compliance requirements of the UWMP Act. As shown in Table 2.1, the City meets this requirement as it has 4,372 municipal connections and supplied 1,670 AF in fiscal year (FY) 2025.

Table 2.1 Submittal Table 2-1 Retail: Public Water Systems Submittal Table 2-1 Retail: Public Water Systems
Public Water System Number Public Water System Name Number of Municipal Connections 2025
Volume of
Water Supplied
2025 (AF)
Add additional rows as needed
CA3010100 City of La Palma 4,372 1,670
Total 4,372 1,670
DWR NOTES:

Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

This table identifies the unit of measure selected in Table 2-3.

The City opted to prepare its own UWMP (Table 2.2) and comply with the Water Code individually, while closely coordinating with MWDOC and various key entities as discussed in Chapter 2.2 to streamline regional integration. The UWMP Checklist was completed to confirm the compliance of this UWMP with the Water Code (Appendix A). All DWR standardized tables are provided in Appendix B. The City has selected to report demands and supplies using fiscal year as the basis (Table 2.3).

Table 2.2 Submittal Table 2-2: Plan Identification
Submittal Table 2-2: Plan Identification
Select One or
Both Type of Plan Name of Regional Alliance or RUWMP
(Drop Down List)
Individual UWMP
If Water Supplier is also a member of a SB X7-7 Regional Alliance, select name from the drop-down. Orange County 20x2020 Regional Alliance Regional Urban Water Management Plan (RUWMP)
If Supplier selected RUWMP, select name from the dropdown.

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Table 2.3 Submittal Table 2-3: Supplier Identification
Submittal Table 2-3: Supplier Identification
Type of Supplier (select one or both)
Supplier is a wholesale supplier
Supplier is a retail supplier
Fiscal or Calendar Year (select one)
UWMP Tables are in calendar years
UWMP Tables are in fiscal years
If using fiscal years provide month and date that the fiscal year begins (mm/dd) 7/1
Units of measure used in UWMP
(select from drop down)
Unit AF
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.

2.2 Coordination and Outreach

2.2.1 Integration with Other Planning Efforts
The City, as the retail supplier to its customers, coordinated the preparation of this UWMP with its water supplier wholesaler, MWDOC, the Orange County Water District (OCWD) as the manager of the Orange County Groundwater Basin, and Orange County Sanitation District (OCSD), its regional wastewater management agency. The City also developed this Plan in conjunction with other regionally consistent efforts such as population projections from the Center for Demographic Research at California State University, Fullerton (CDR) and the Orange County Water Deland Projection Model Technical Memorandum.

Key planning and reporting documents that were used to develop this UWMP are listed below:
 Metropolitan Water District of Southern California’s (MET) 2025 UWMP uses assumptions that fall within the plausible futures contemplated in MET’s Integrated Water Resources Plan to evaluate MET’s future imported water supply reliability.
 MET’s 2020 Integrated Water Resources Plan (IRP) Regional Needs Assessment is a long-term, scenario-based planning document that guides Metropolitan’s programs and investments to ensure reliable water supplies in Southern California and provides a basis for water supply reliability in Orange County.
 MET’s Climate Adaptation Master Plan for Water (CAMP4W) is an ongoing planning and decision-making tool that accounts for the complexities and uncertainties of climate change. Part of the second phase of MET’s long-term IRP planning process, CAMP4W incorporates the results and findings of MET’s 2020 IRP Regional Needs Assessment into a collaborative process to identify and evaluate integrated regional solutions.

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 MET’s 2025 Water Shortage Contingency Plan (WSCP) provides a water supply availability assessment and guide for MET’s intended actions during water shortage conditions.  MWDOC’s 2025 WSCP provides a water supply availability assessment and structured steps designed to respond to actual conditions that will help maintain reliable supplies and reduce the impacts of supply interruptions.
 MWDOC’s 2023 Orange County Water Reliability Study is a planning document to help guide planning for future water supply reliability for water providers in Orange County and provide input on regional water supply issues for MET.
 2025 Orange County Water Demand Projection Model Technical Memorandum is a collaborative effort amongst MWDOC, OCWD, and all retail water suppliers in Orange County that developed water demand projections to produce regionally consistent forecasts across all Orange County water agencies.
 OCWD’s Groundwater Resilience Plan (GRP - February 2025) is an adaptive strategies management plan outlining strategic projects to secure reliable future water supplies in the Orange County Basin.
 OCWD’s 2023-24 Engineer’s Report provides information on the groundwater conditions, water supply and basin utilization of the Orange County Basin.  2022 Basin 8-1 Alternative is an alternative to the Groundwater Sustainability Plan (GSP) for the Orange County Basin, provides significant information related to sustainable management of the basin in the past and hydrogeology of the basin, including groundwater quality and basin characteristics, and addresses DWR’s recommendations to ensure long-term basin sustainability.  City of La Palma Local Hazard Mitigation Plan (2020) provides the basis for the seismic and other natural and natural disaster risk analysis of the water system facilities.

2.2.1.1 Statewide Water Planning
In addition to regional coordination with the various agencies described above, the City as a MWDOC member agency is currently a part of MET’s statewide planning effort to reduce reliance on the water imported from the Delta.

It is the policy of the State of California to reduce reliance on the Delta in meeting California’s future water supply needs through a statewide strategy of investing in improved regional supplies, conservation, technology innovation, partner collaborations and water use efficiency measures. This policy is codified through the Delta Stewardship Council’s Delta Plan Policy WR P1 (WR P1) and is measured through Supplier reporting in each Urban Water Management Planning cycle. WR P1 is relevant to water suppliers that plan to participate in multi-year water transfers, conveyance facilities, or new diversions in the Delta.

Additionally, with the recent amendments to the Bay Delta Plan, tributary flow objectives to the Delta are being updated to account for quality and habitat improvements for local environmental resources. This results in reduced reliance on Delta water supplies. Since 2022, the Bay-Delta Plan Amendment update has been in development. This effort considers additional tributaries from the southern San Joaquin Valley, triggering a re-evaluation of Delta flow requirements and conservation objectives, which ultimately may impact available supply to the State Water Project (SWP).

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Through significant local investment, collaboration at both a local and regional scale and integration with MWDOC’s water use efficiency strategies and conservation programs, the City has demonstrated a reduction in Delta reliance. For member agencies of MWDOC that receive imported water from MET, these agencies have passively demonstrated a reduction in Delta reliance and a subsequent improvement in regional self-reliance by participating in MWDOC led regional strategies. A detailed description and documentation of the City’s consistency with Delta Plan Policy WR P1 is included in Chapter 7.4 and Appendix C.

2.2.2 Wholesale and Retail Coordination
The City developed its UWMP in conjunction with MWDOC’s 2025 UWMP. As a retail water supplier, the City provided its historical water use and water use projections data to MWDOC (Table 2.4).

The City also has been taking part in multiple regional programs administered by MWDOC to assist retail agencies in meeting various State compliance, such as the OC Regional Alliance for SBx7-7 compliance, regional water loss program or SB555 compliance, and regional water use efficiency programs. Chapters 5 and 9 provide detailed information on these programs.

Table 2.4 Submittal Table 2-4 Retail: Water Supplier Information Exchange Submittal Table 2-4 Retail: Water Supplier Information Exchange Water Code Section 10631(h)
The retail Supplier has informed the following wholesale supplier(s) of projected water use.

Wholesale Water Supplier Name
Add additional rows as needed
Municipal Water District of Orange County
Orange County Water District

2.2.3 Public Participation
For further coordination with other key agencies, and to encourage public participation in the review and update of this Plan, the City held a public hearing on June 2, 2026 and notified key entities and the public per the Water Code requirements. Chapters 10.2 and 10.3 describe these efforts in detail.

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CHAPTER 3 SYSTEM DESCRIPTION
The City of La Palma (City) was incorporated in October 1955 and lies in north Orange County at the border of Los Angeles County and is bounded by the City of Cerritos on the north and west, the City of Buena Park on the east, and the City of Cypress on the south. The City serves water within its city limits and to a portion of the City of Cerritos. The City operates two groundwater wells, two reservoirs with a total capacity of 4.5 million gallons (MGs), and manages a 39.7-mile water mains system with approximately 4,372 service connections.

Lying in the South Coast Air Basin (SCAB), its climate is characterized by southern California’s “Mediterranean” climate with mild winters, warm summers and moderate rainfall. In terms of land use, the City is almost built out with predominantly single-family residential units. Moving forward, the City will continue planning for its Regional Housing Needs Assessment (RHNA) allocation and major future and future developments may potentially include additions of accessory dwelling units (ADUs). The current population of 15,141 is projected to decrease by 0.05 percent over the next 25 years.

3.1 Agency Overview
This section provides information on the formation and history of the City, its organizational structure, roles, and relationship to the Municipal Water District of Orange County (MWDOC).

3.1.1 Formation and Purpose
The City was incorporated as Dairyland in October 1955 and remained so until the dairies relocated. The name was changed in 1965 to La Palma in reflection of Orange County's Spanish heritage and the City’s main street, La Palma Avenue.

Soon after the small farming community began its life, City planners decided that the City should benefit from a long-term program for orderly development. The Civic Center and Central Park, now La Palma's premier gathering places, were among the first projects to be completed to better the community. The City's major redevelopment project, Centerpointe, added new commercial and light industrial uses in the early 1980s. La Palma is a well-balanced city, which prides itself on a responsive municipal government and a strong sense of community.

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3.1.2 City Council
The City is run by the Council-manager form of government. Five Council Members are elected at-large and serve 4-year staggered terms. The mayor’s position is filled by one of the Council Members, who vote each year to fill this position. Other officials include the City Manager and Community Development & Public Works Director. The City Manager is appointed by the City Council. Other City managerial positions are filled by the City Manager. The current Council Members are:
 Nitesh P. Patel, Mayor
 Debbie S. Baker, Mayor Pro Tem
 Mark I. Waldman, Council Member
 Janet Keo Conklin, Council Member
 Vikesh P. Patel, Council Member

3.1.3 Relationship to MWDOC
The City is one of MWDOC’s 27 member agencies purchasing imported water from MWDOC, Orange County’s wholesale water supplier and a member agency of the Metropolitan Water District of Southern California (MET). The City’s location within MWDOC’s service area is shown on Figure 3.1.

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Figure 3.1 Regional Location of the City of La Palma and Other MWDOC Member Agencies

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3.2 Water Service Area and Facilities

3.2.1 Water Service Area
The City lies in north Orange County at the border of Los Angeles County and is bounded by the City of Cerritos on the north and west, the City of Buena Park on the east, and the City of Cypress on the south.

The City is located approximately 18 miles southeast of downtown Los Angeles and serves water to the City of La Palma and to a portion of the City of Cerritos. A small portion of the City’s potable demand is served by Golden State Water Company (GSWC) including residential and school properties. A map of the City's water service area is shown in Figure 3.2.

Figure 3.2 City of La Palma Water Service Area

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3.2.2 Water Facilities
The City’s water delivery system serves approximately 4,382 connections through a network of about

39.7-miles of water mains. The main source of water supply is groundwater, which is delivered to the system by two wells. As a supplemental source, the City has a connection to MET’s supply through MWDOC. The City also has two existing interconnections with the City of Cerritos and one interconnection with the City of Buena Park for emergency purposes. For storage, the City has two reservoirs of 2.5 and

2.0 MG capacity. Each reservoir also has a booster pumping station to pump water into the system. The topography of the City is flat, with very little variation in elevation, and the City has only one pressure zone. The City has also installed a telemetry system to automatically monitor the operation of the water facilities. The operation and management of the City’s water system fall within the jurisdiction of the City’s Department of Community Development and Public Works.

3.3 Climate
The City's service area is located within the South Coast Air Basin (SCAB) that encompasses all of Orange County, and the urban areas of Los Angeles, San Bernardino, and Riverside counties. The climate in the SCAB area is characterized by southern California’s “Mediterranean” climate: a semi-arid environment with mild winters, warm summers, and moderate rainfall.

Local rainfall has limited impacts on reducing water demand in the City, except for the case of landscape irrigation demand. For example, in August 2023, Orange County as a region experienced the lowest seasonal water demand due to significant summer precipitation events from Tropical Storm Hilary. The increase in precipitation allowed landscape irrigation systems to be turned off, however other municipal and industrial uses (e.g. consumption, processing, and washing still remained the same).

Water that infiltrates into the soil may enter groundwater supplies depending on the local geography.

However, due to the large extent of impervious cover in Southern California, rainfall runoff quickly flows to a system of concrete storm drains and channels that lead directly to the ocean. Orange County Water District (OCWD) has successfully captured stormwater along the Santa Ana River and in recharge basins for years and used it as an additional source of supply for groundwater recharge. Based on the 2022 Basin 8-1 Alternative Plan Update, OCWD captured an average annual stormwater volume of approximately 54,000 AF over the period of five years, from Water Year 2016-17 to 2020-21.

MET's water supplies come from the State Water Project (SWP) and the Colorado River Aqueduct (CRA) are influenced by climate conditions in northern California and the Colorado River Basin, respectively.

Both regions have variable hydrologic conditions that can significantly affect MET’s supplies from year to year. This past decade has seen dramatic swings in annual precipitation, especially in the form of snowpack, which directly affect SWP supply allocations. Similarly, the Colorado River Basin also experienced year-to-year swings in hydrology ,and due to the prolonged drought conditions since 2000, storage within the Colorado River system has declined to less than half of its reservoir capacity and has been fluctuating at that level (MET, 2025).

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3.4 Population, Demographics, and Socioeconomics

3.4.1 Service Area Population
The City serves a 2025 population of 15,141 according to the Center for Demographic Research at California State University, Fullerton (CDR). Overall, the population is projected to decrease 0.05 percent by 2050. Table 3.1 shows the population projections in five-year increments out to the year 2050 within the City’s service area.

Table 3.1 Submittal 3-1 Retail: Population - Current and Projected Submittal Table 3-1 Retail: Population - Current and Projected Water Code Section 10631(a)
Population
Served
2025 2030 2035 2040 2045 2050(opt)
15,141 15,077 15,138 15,237 15,227 15,134
NOTES:

Source: Center for Demographic Research at California State University, Fullerton, 2025.

3.4.2 Demographics and Socioeconomics
As shown below in Table 3.2, the total number of dwelling units in the City service area is expected to increase by 6.6 percent in the next 25 years from 5,268 in 2025 to 5,616 in 2050.

Table 3.2 City’s Service Area Dwelling Units by Type
Dwelling Units 2025 2030 2035 2040 2045 2050
Single Family 3,894 3,899 3,905 3,905 3,905 3,905
All Other(1) 1,374 1,443 1,510 1,577 1,644 1,711
Total 5,268 5,342 5,415 5,482 5,549 5,616
Notes:

Source: Center for Demographic Research at California State University, Fullerton, 2025. (1) Includes duplex, triplex, apartment, condo, townhouse, mobile home, etc. Yachts, houseboats, recreational vehicles, vans, etc. are included if is primary place of residence. Does not include group quartered units, cars, railroad box cars, etc.

In addition to the types and proportions of dwelling units, various socio-economic factors such as age distribution, education levels, general health status, income and poverty levels affect the City’s water management and planning. Based on the U.S. Census Bureau's 2023 American Community Survey, the City has about 21 percent of population of 65 years and over, 60 percent between the ages of 18 and 64 years, and 19 percent under the age of 18 years. Of the City’s population over 25 years of age,

93.9 percent is at minimum a high school graduate, with 48.8 percent of this age group having at least a bachelor’s degree.

3.4.3 Demographic Projection Methodology
CDR is a collaborative research center established in 1996 to provide accurate and timely demographic data on population, housing, and employment in Orange County. CDR serves as Orange County’s authoritative source for demographic information. The City obtains its service area population and dwelling unit data from MWDOC via CDR. MWDOC contracts with CDR to update the 2010 population estimates through the current year and to provide an annual estimate of population served by each of its

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retail water suppliers within its service area. CDR uses geographic information system (GIS) mapping and data from the 2000, 2010, and 2020 U.S. Decennial Censuses, State Department of Finance (DOF) population estimates, and the CDR annual population estimates and Housing Inventory System (HIS).

These annual estimates incorporate annual revisions to the DOF annual population estimates, often for every year back to the most recent Decennial Census. As a result, all previous estimates are set aside and replaced with the most current set of annual estimates. Annexations and boundary changes for water suppliers are incorporated into these annual estimates.

Demographic projections used for this UWMP reflect the most recently available set of projections developed by CDR based on its 2022 Orange County Projections. Demographic projections for Orange County are updated every 4 years, with the next set of projections expected in the late fall of 2026. The 2022 Orange County Projections accounted for Draft RHNA rezone sites with jurisdictions including the number of dwelling units that are most likely to occur/get built by the end of 2050 under assumptions and trends existing at the time of the forecasting effort, including a parcel-level inventory of additional housing capacity from sites that were to be rezoned to accommodate the 6th RHNA cycle. In the summer of 2025, projections by water supplier for population and dwelling units by type were estimated using the 2022 Orange County Projections dataset. Growth for each of the five-year increments was allocated using GIS and a review of the traffic analysis zones (TAZ) data with a 2023 aerial photo. The growth was added to the 2025 estimates for each respective water supplier.

3.5 Land Uses

3.5.1 Current Land Uses
Single-family detached housing is the predominant land use in the City, covering over 50 percent of the land area. The majority of the housing was built prior to 1980. Neighborhoods include landscaping and sidewalk systems connecting residences to schools, as well as an open-space corridor that crosses the width of the City. Multiple-family housing comprises 8 percent of the geographic area of the City. The City also includes a business district north of Orangethorpe Avenue and the Riverside/Artesia (SR-91) freeway.

The business/industrial sectors of the City include the Centerpointe (formerly designated Multi-use Business), which is a master-planned multi-use business district with a high-rise hotel, office buildings, restaurants, entertainment uses, research and development, and light manufacturing uses. The industrial sector is located north of Centerpointe, and is made up of large, single-story buildings for manufacturing, assembly, warehousing, and other light industrial uses. Public open space is comprised of lands dedicated for park space, school yards, and pedestrian and bicycle trails. Open space encompasses approximately 37 acres, the majority of which is contained within Central Park and the City’s Promenade, a 175-foot strip of open space which also serves as a Southern California Edison easement that spans the width of the City developed with walking trails and green space between, and paralleling, Houston and La Palma Avenues.

Smaller open space areas are located within easements along Coyote Creek channel.

3.5.2 Projected Land Uses
The 2014 General Plan outlines high-density mixed-use redevelopment of approximately 81 acres within the Multi-use Business district at the north end which would increase daytime and residence populations of the City. City planning officials are contemplating expanding this ‘Focus Area’ to include redevelopment of approximately 57 acres of the General Industrial land use to the north. The major redevelopment would

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include a mixed-use of high-density residential and non-residential land uses reflecting smart-growth to promote economic health by enhancing mobility and more efficient development of infrastructure. These developments would change the City’s total water demand in the future.

It should be noted that the 2025 Orange County Water Demand Projection Model discussed in Chapter 4 was based on CDR’s 2022 Orange County projections. The developments listed above may have been added or modified since. As a result, the future demands associated with these developments may increase the City’s water demand beyond what is presented in this UWMP.

In addition to the above developments, the City will continue planning for the Regional Housing Needs Assessment (RHNA) allocation imposed by the State. Additionally, new developments may potentially include Accessory Dwelling Units (ADUs), while it is also anticipated that policy changes will make it easier for homeowners to add ADUs to existing residential properties.

The following requirements and changes in laws will impact the City’s future land use moving forward:
 Regional Housing Needs Assessment (RHNA) – State law requires jurisdictions to provide their share of the RHNA allocation. SCAG determines the housing growth needs by income for local jurisdictions through RHNA. The City’s RHNA allocation for 2021-2029 is 802 dwelling units. This includes 224 units for very low-income households, 140 units for low-income households, 137 units for moderate-income households, and 301 units for above moderate-income households. As stated in the City’s 2021–2029 Housing Element, the City plans to implement future zoning and regulatory updates, adopt objective design standards, and monitor housing production to ensure continued compliance with its RHNA obligations.
 Accessory Dwelling Units (ADUs) – ADUs are separate small dwellings embedded within residential properties. There has been an increase in the construction of ADUs in California in response to the rise in interest to provide affordable housing supply. Since 2020, several landmark laws were passed by State Legislature, updating ADU law to simplify the construction, rental, and sale of ADUs in California.

The most significant laws that have recently come into effect include:
» AB-1033 Accessory dwelling units: local ordinances: separate sale or conveyance which authorizes local governments to adopt ordinances permitting the sale of ADUs separately from the primary residence as condominiums.
» AB-976 Accessory dwelling units: owner-occupancy requirements which prohibits a local agency from requiring owner-occupancy for property owners to build and rent an ADU. » AB-1154 Junior accessory dwelling units which no longer requires owner-occupancy for Junior ADUs (JADUs) as long as they have their own bathroom.
» AB-1332 Accessory dwelling units: preapproved plans which requires local agencies to develop a program for pre-approved ADU plans, with projects using these plans having to be approved or denied within 30 days.
» SB-543 Accessory dwelling units and junior accessory dwelling units which requires local agencies to determine if an ADU/JADU application is complete within 15 business days of submittal, revises ADU size to now be measured by “interior livable space”, and now re-defines a JADU to be no more than 500 square feet of interior livable space.

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» SB-1211 Land use: accessory dwelling units: ministerial approval which authorizes multi-family property owners to build up to eight detached ADUs on a single lot, provided that the number of ADUs does not exceed the number of existing primary units. » AB-2533 Accessory dwelling units: junior accessory dwelling units: unpermitted developments which prohibits local agencies from denying permits for unpermitted ADUs/JADUs constructed before January 1, 2020 based on code violations unless the structure is a health or safety hazard.

In 2024, a total of 6,162 new residential units were permitted in Orange County, including those for ADUs (CDR, 2025). CDR projects that by 2050, approximately 13,000 more ADUs will be built in Orange County, with no ADUS currently being expected within the City’s service area. Nonetheless, an increase in ADUs in the City’s service area is likely to result in an increase in number of people per lot of land. Depending on whether the addition of ADUs results in a net replacement of irrigated area (or other high water use features such as swimming pools), ADUs could increase or decrease water demands.

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CHAPTER 4 WATER USE CHARACTERIZATION
One of the main objectives of an Urban Water Management Plan (UWMP) is to provide an insight into the projected future water demands and supplies. This chapter describes the City of La Palma’s (City) current and future water demands for their service area, factors that influence demands, and the methodology used to forecast future water demands over the next 25 years. For the 2025 UWMPs, water demand projections will span from planning year 2025 through planning year 2050.

Known for its suburban coastal communities and densely populated inland areas, Orange County has evolved greatly from its beginnings as an agricultural region. As some of the earliest cities in Orange County, from 1928 to 1931 the Cities of Anaheim, Fullerton, and Santa Ana all joined with 10 other southern California cities to form the Metropolitan Water District of Southern California (MET) with the ambitious dream to bring Colorado River water across the Mojave Desert. The Municipal Water District of Orange County (MWDOC) later joined MET as a member agency in 1951, and with the merger with Coastal Municipal Water District in 2001, now represents the remainder of Orange County to provide and manage the imported water supplies within its service area. Orange County is now mostly comprised of residential, mixed-use, and commercial developments, with less industry in the region. Agriculture in the region has also declined significantly as Orange County has grown more suburban. Thus, modern-day water use within Orange County can be largely summarized by the following four demand sectors:
 Single-family Residential.
 Multifamily Residential.
 Commercial, Industrial, and Institutional (CII).
 Dedicated Irrigation (potable, recycled & raw water).

Figure 4.1 shows Orange County’s overall historical water usage compared to population since 1990, when local water conservation programs were first established. As shown, from the early 1990s through the mid-2000s, Orange County’s water usage increased as the population increased. Population figures slowed significantly in 2018 and began to decrease during the COVID-19 Pandemic in 2020-2021. Since 2007, retail, municipal, and industrial water use in Orange County has declined due to multiple contributing factors. Decades of sustained investments in water-use efficiency and public education have led to significant adoption of water-efficient appliances and fixtures, and increased public awareness of the need to use water wisely. Furthermore, in response to recurring droughts, growing urban demand, and increasingly limited water supplies, multiple regulatory requirements to promote water conservation have evolved and been implemented over the past several years throughout California and Orange County.

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Figure 4.1 Historical Water Use and Population in Orange County Orange County’s trending decline in water usage can most notably be attributed to Orange County water agencies’ past efforts to achieve regional and individual compliance with Senate Bill (SB) X7-7, the Water Conservation Act of 2009, through the Orange County 20x2020 Regional Alliance and compliance with Executive Order (EO) B-29-15. EO B-29-15 mandated 25 percent reduction in potable water use in response to the 2013-2014 drought. Furthermore, Orange County water agencies’ ongoing progress towards achieving SB 606 and Assembly Bill (AB) 1668, the “Making Conservation a California Way of Life” legislation, water use objectives continue to exemplify Orange County water agencies’ commitment to water conservation, water use efficiency, and overall reduction in potable water usage in recent decades.

In 2025, MWDOC and Orange County Water District (OCWD), in collaboration with MWDOC’s member agencies and the Cities of Anaheim, Fullerton, and Santa Ana, led the effort to develop the 2025 Orange County Water Demand Projection Model. The Orange County Water Demand Projection Model (MWDOC, 2025) was used to project long-term water demand under three hydrologic conditions (normal year, single dry year, and five consecutive dry years) over a 25-year horizon in 5-year increments, consistent with the 2025 UWMP requirements.

Although Orange County demands are forecast to be relatively flat into the future, with water use efficiency efforts counterbalancing new growth, Figure 4.2 shows that annual variations in weather could cause high fluctuations. Some examples of this are described below:
 Single-family consumption is highly seasonal, and the model correlates well with seasonality and temperature by capturing fluctuations in single-family outdoor irrigation.  Multi-family use is generally less responsive to weather than single-family demands, as much of multi-family outdoor irrigation has been shifted into the irrigation-specific water use sector

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(dedicated irrigation meters), and generally newer multi-family dwellings in Orange County have comparatively less landscaped area than generally older single-family dwellings due to Model Water Efficient Landscape Ordinances (MWELO) mandated since 1993. Seasonal price elasticity varies the least between months for the multi-family sector.
 Commercial, Industrial and Institutional use is positively correlated to each job proportion as well as gross domestic product throughout Orange County, which means a higher amount of CII jobs and production value trend in an increase in water demands.  Irrigation is the most responsive to temperature and precipitation compared to the other sectors.

Figure 4.2 Projected Water Use Across All Orange County Water Agencies In terms of future development, North Orange County is substantially built out, with a majority residential land uses with some mixed-use areas dedicated to commercial, institutional, and governmental uses.

Future developments planned in North Orange County are mainly redevelopment and infill projects. As for the City’s service area specifically, future developments include redevelopment projects, potential Accessory Dwelling Units (ADUs), and additional residential units to meet the City’s Regional Housing Needs Assessment (RHNA) allocation, which will all shape the City’s future water use.

Water use within the City’s service area has been relatively constant in the past five years, with an annual average total water use of approximately 1,741 acre-feet (AF). Following one of the worst droughts in California history between 2017 and 2022, the significant wet year in 2023 saw a decrease in overall water use from FY 2021-22 to FY 2022-23 in the City’s entire service area.

Water use in FY 2024-25 included 1,670 AF potable water, with the City’s water use being primarily residential. The projected water use in 2050 is 1,721 AF for potable water.

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4.1 Water Use in the Last Five Years
The five-year average water use within the City’s service area is approximately 1,741 AF provided by potable sources. Demand trends have regionally remained flat due to water-use efficiency efforts and increased precipitation in recent wet years, such as FY 2023. As mentioned in Chapter 3, the City is almost completely built out and population projections are expected to slightly decrease. Total demands have remained relatively stable due to ongoing water conservation programs and improved water use efficiency efforts.

FY2020-21 through FY 2021-22 saw the highest water uses over the last five years due to region-wide drought conditions. FY2022-23 proved to be one of the wettest years on record in the State and the City saw a general decrease in water demand following this wet year, as precipitation offsets landscape irrigation demands. These year-to-year fluctuations in precipitation will continue to influence the City’s annual demands. In general, the City saw a decrease in demands of 16.1 percent over the 5-year reporting period.

Table 4.1 presents the City’s service area existing water use by source for direct uses. There are no indirect uses within the City’s service area. The City’s service area total water usage in FY 2024-25 was 1,670 AF (Table 4.1). The total usage was met through a combination of potable sources, including groundwater and imported water. In FY 2024-25, about 97.1 percent of the total demand was met through Orange County Basin groundwater.

Table 4.1 Submittal Table 4-1 Retail: Total Uses for Potable and Non-Potable Water – Actual Submittal Table 4-1 Retail: Total Uses for Potable and Non-Potable Water – Actual Water Code Section 10631(d)(1)
Use Type
Additional Description
(as needed)
2025 Actual Water Use
Drop down list
May select each use multiple times
These are the only use types that will
be recognized by the WUEdata online
submittal tool
Potable or
Non-Potable
(OPTIONAL)
Drop down list
Volume (AF)
Add additional rows as needed
Single Family Potable 1,018
Multi-Family Potable 383
Commercial Includes Institutional, Industrial Potable 199 Landscape Represents large landscape (with irrigation
meters) served by potable water Potable 65
Distribution System Water Loss Potable 5
Subtotal Potable 1,670
Subtotal Non-Potable 0
Total 1,670
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

NOTES:

Table 4.1 summarizes the City’s potable water demand for FY2024-25; a total of 1,670 AF of potable water was used. The City has a mix of single and multi- family residential water use which account for

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83.9 percent of their total potable water demand. Combined commercial, industrial, and institutional use accounts for 11.9 percent of total potable demand while landscape irrigation accounts for 3.9 percent of total potable demand. Distribution system water loss was 0.3 percent in FY 2024-25.

Since the City is essentially built-out and with the low population growth rates and continual water conservation efforts, demands are not expected to increase significantly.

4.2 Projected Water Use
The water use projection for this UWMP is separated into a near-term period covering the next five years (2026-2030) and a long-term period extending from 2030 through 2050.

The water use projection is based on the 2025 Orange County Water Demand Projection Model Technical Memorandum (TM), which is included in Appendix H of this UWMP. The methodology used in this demand forecast links water use statistically to a set of explanatory variables through a regression, or econometric, model. Section 4.3 offers a description of the methodology used to calculate the City’s demand projections.

4.2.1 Water Use Projections for 2026-2030
Total demands (direct) are met through imported water (treated) and groundwater. The City utilizes the projected total demands to incorporate the best available planning information when projecting the imported water demands of its service area. The City’s total water demand projection for the next five years is shown in Table 4.2. As shown, the City’s total service area water demands are expected to gradually decrease over the next five years (2026 to 2030), due to a projected decline in the service area’s M&I demands in the short term. The City does not project any non-potable demands for its service area in the next five years.

Table 4.2 City of La Palma’s Service Area Total Potable for 2026-2030 Fiscal Year Ending 2026 2027 2028 2029 2030
Total Water Demand (AF) 1,738 1,729 1,723 1,711 1,705

4.2.2 Water Use Projections for 2030-2050
The City’s service area’s total water demands (by use type) for 2030-2050 are shown in Table 4.3. By 2050, total water demand is projected to be 1,721 AF, a 3 percent increase from the 2025 demand of 1,670 AF.

Table 4.4 indicates additional information for both future conservation efforts and low-income water demands included in the projections. Table 4.5 presents the passive water savings included in Table 4.3 projections for 2030-2050.

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Table 4.3 Submittal Table 4-2 Retail: Total Uses of Potable, and Non-Potable Water - Projected Submittal Table 4-2 Retail: Total Uses of Potable, and Non-PotableWater - Projected Water Code Section 10631(d)(1)
Use Type
Additional
Description
(as needed)
Projected Water Use
(Report To the Extent that Records are Available)
Drop down list
May select each use multiple times
These are the only Use Types that
will be recognized by the WUEdata
online submittal tool
Potable or
Non-Potable
(OPTIONAL)
Drop down list
2030
(AF)
2035
(AF)
2040
(AF)
2045
(AF)
2050
(opt)
(AF)
Add additional rows as needed.

Single Family Potable 993 991 992 987 982
Multi-Family Potable 222 228 234 239 244
Commercial Includes Institutional
and Industrial uses
Potable 249 251 253 253 253
Landscape Includes Agriculture
use
Potable 170 170 171 170 170
Distribution System Water Loss Includes Other uses Potable 71 71 72 72 72 Subtotal Potable 1,705 1,711 1,722 1,721 1,721
Subtotal Non-Potable 0 0 0 0 0
Total 1,705 1,711 1,722 1,721 1,721
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

NOTES: Source – 2025 Orange County Water Demand Projection Model Forecast for the City of La Palma Table 4.4 Submittal Table 4-3 Retail: Inclusion in Water Use Projections Submittal Table 4-3 Retail: Inclusion in Water Use Projections Water Code Section 10631 (a), 10631 (d)(4)(A), and 10631 (d)(4)(B) Are Future Water Savings Included in Projections?
Drop down list (y/n) Yes
If "Yes" to above, state the section or page number, in the cell to the right, where citations of the codes, ordinances, or otherwise are utilized in demand projections are found.

Optional Suppliers may complete Optional Submittal Table 4-4 R to quantify the expected savings.

Chapter 4.3
Are Lower Income Residential Demands Included In Projections? Drop down list (y/n) Yes
Optional If the method for accounting Lower Income Residential Demands has been included, provide page number where this accounting can be found. Chapter 4.3 DWR NOTES: Additional guidance is provided in Appendix K.

NOTES: Future water savings include passive conservation (defined as water savings that occur without incentives).

Active conservation (defined as water savings that occur with incentives) is not included in the projections.

The demand projection methodology accounted for the entire population of the service area (i.e. all income levels).

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Table 4.5 Optional Submittal Table 4-4 Retail: Passive Water Savings Projections OPTIONAL Submittal Table 4-4 Retail: Passive Water Savings Projections Water Code Section 10631(d)(4)(A)
Description
(Codes, Standards, Ordinances, or Plans)
Passive savings
2030 (AF) 2035 (AF) 2040 (AF) 2045 (AF) 2050 opt
(AF)
Add additional rows as needed
23 23 23 23 23
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.

NOTES: Passive conservation here is defined as water savings that occur without incentives. Based on the 2025 Orange County Water Demand Projection Model, passive conservation is assumed to equal a 1.9% decrease in residential demand due to conservation by 2030 (linearly extrapolated), then remains constant in subsequent years.

Total potable water demands are projected to increase to 1,721 AF by the year 2050, an increase of about

0.9 percent between 2030 and 2050 (Table 4.3). It is projected that combined single- and multi-family residential water use will account for 71.3 percent of total potable water demand. Combined commercial, institutional, and industrial water use is expected to account for 14.7 percent, and landscape irrigation water use will account for 9.9 percent of total potable water use in the City by 2050. Distribution system water loss and other uses will account for 4.2 percent of total potable water demands.

4.3 Water Demand Projection Methodology
In 2025, MWDOC and OCWD, in collaboration with MWDOC’s member agencies and the Cities of Anaheim, Fullerton, and Santa Ana, led the effort to develop the 2025 Orange County Water Demand Projection Model, (MWDOC, 2025). This effort developed a demand model by regressing historical water consumption data provided by each Orange County water agency against several explanatory variables known to influence water demand (including weather, water price, regional economic conditions, and housing density). The water demand projections were for the Orange County region as a whole and provided retail agency specific demands, spanning the years of 2025-2050. The full TM can be found in Appendix H.

The demand projections created four econometric, or regression, demand models representing the following four water billing sectors for each Orange County retail agency:
 Single-family Residential.
 Multifamily Residential.
 Commercial, Industrial, and Institutional (CII).
 Dedicated Irrigation (potable, recycled & raw water).

Prior to developing the forecasts, model calibration and fine tuning for each of the four demand sectors occurred at the individual retail agency level. The demand across all four models, plus other uses for each agency, is summed to a total forecast for each agency, the MWDOC service area, the OCWD service area, and total Orange County.

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The demand projection methodology accounted for the entire population of each individual retail agency’s service area (i.e., all income levels), thus accounting for the water demand projections for lower income households within the City’s service area.

4.3.1 Econometric Approach, Data Acquisition, and Model Development A regression, or econometric, approach to demand forecasting statistically links retail level water use to weather, economic, and socioeconomic factors (explanatory variables). The model relies on a comprehensive dataset of historical water-use data for almost 40 different billing sectors collected from Orange County retail agencies. MWDOC obtained explanatory variables from reputable sources, including weather databases and Census-based reports. The explanatory variables used in the regression were based on industry experience regarding what factors affect water use nationwide and in Southern California.

By statistically linking water use to explanatory variables, the econometric models provide a robust foundation for understanding variability and projecting future consumption patterns. Modeled water use is the product of the driver count (e.g., number of accounts), and the rate of water use per driver:

𝑊𝑊𝑊𝑊𝑊𝑊𝑊𝑊𝑊𝑊 𝑈𝑈𝑈𝑈 = 𝐷𝐷 𝐷𝐷𝐷𝐷 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 × 𝑅𝑅 𝑜𝑜 𝑈𝑈𝑈𝑈 𝑝𝑝 𝐷𝐷 𝐷𝐷𝐷𝐷 Each of the four demand sectors modeled (single family, multifamily, CII, and irrigation) has a separate equation. Driver units change into the future based on housing, employment, and population projections.

The rate of water use per driver is based on the historical response of the use rate to explanatory variables (measured by coefficients) and the future values of those same explanatory variables.

Linear regression produces the coefficients for each explanatory variable to closely reproduce the historical rate of use per driver unit. The coefficients explain how (both in terms of magnitude and sign) water use responds to changes to explanatory variables.

MWDOC identified driver units based on data provided by agencies and the Center for Demographic Research at Cal State Fullerton (CDR) that can be easily projected into the future. The rate of water use per driver is based on agency provided billing sector uses from 2010 through 2024. Table 4.6 shows the driver units and rate of use for each of the four models.

Table 4.6 Summary of Demand Sectors
Sector Driver Units Rate of Use Definition
Single-family Residential Accounts gallons/account/day
Multifamily Residential gallons/account/day
Commercial, Institutional, Industrial (CII) Jobs gallons/job/day Dedicated Irrigation (potable, recycled & raw water) Accounts gallons/account/day The rates of water use for each sector model are based on the historical responses to explanatory variables, and the future values of those explanatory variables. Addressing multiple influences on demand improves the accuracy and precision of all estimated parameters, and the modeling team identified a large range of explanatory variables based on past experience with demand modeling and available data.

Table 4.7 displays the explanatory variables.

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Table 4.7 Summary of Historical Data Collected for Model Development Dataset Data Source(s)
Observed weather (monthly precipitation,
monthly maximum temperature)
Parameter-elevation Regressions on Independent Slopes Model (PRISM)
Water Price Retail agency provided (2010 – 2024)
Drought Restrictions State Water Resources Control Board Gross Domestic Product (GDP) Federal Reserve Bank of St. Louis Real Gross Domestic Product: All Industries in Orange County, CA
Median Income US Census American Community Survey (ACS) Housing Density US Census American Community Survey (ACS), California State University Fullerton Center for Demographics Research (CDR), Southern California Association of Governments (SCAG) land use data Persons Per Household Relative Sectoral Economic Activity US Census LODES, CDR Passive Efficiency Estimates Analysis of trend indicators and MWDOC/FLUME insight COVID Binary Indicator Assumed active from March 2020 – May 2023 The MWDOC Water Use Efficiency Group provided annual water savings achieved by various active conservation measures. To avoid potential errors in the classification of historical conservation data, total historical conservation was modeled in each sectoral regression model using a linear trend to capture steady change over time. While historical conservation is captured in a linear trend, projected passive conservation is based on best available data from the 2021 Orange County Residential Water Efficiency Potential and Opportunities Study and assumes a 1.9 percent decrease in annual residential demand from 2025 to 2030, at which point passive conservation is projected to remain constant. Future active conservation is not accounted for in baseline demand forecast, as water savings from active programs (programs that require customers to change behavior) are highly specific to retail agencies and to the formulation and timing of their implementation.

The process of identifying the explanatory variables to include in the regression equation and developing coefficients that accurately measure the response of water use to changes in these variables is the most time-intensive part of the demand forecasting process.

Prior to developing the forecasts, model calibration and fine tuning for each of the four demand sectors occurred at the individual retail agency level. The modeling team worked with each retail agency to calibrate sectoral model equations and quantify other uses (those not included in the single-family, multifamily, irrigation, or CII demand sectors).

Figure 4.3 presents the iterative process undergone to develop the econometric demand forecasts.

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Figure 4.3 Econometric Demand Forecast Development Process

4.3.2 Forecasted Demands
Forecasted demand is a function of both the change in driver units into the future as well as the change in explanatory variables. Table 4.8 summarizes the future drivers and variables and assumptions for the baseline forecast. It should be noted that the CDR demographic forecast accounts for both the RHNA allocations and projected increase in Accessory Dwelling Units (ADUs). The 2022 Orange County Projections accounted for Draft RHNA rezone sites1 with jurisdictions including the number of dwelling units that are most likely to occur/get built by the end of 2050 under assumptions and trends existing at the time of the forecasting effort.
1 For the 2022 Orange County Projections, CDR collected initial draft input from local jurisdictions in September 2021 on their anticipated jurisdiction-level housing growth for each projection year. In December 2021-February 2022, CDR reviewed and extracted data from jurisdictions’ draft housing elements to create a parcel-level inventory of additional housing capacity from sites that were to be rezoned to accommodate the 6th RHNA cycle. These were reviewed by jurisdictions in spring 2022.

Jurisdictions completed the rezoning of the final sites after their housing elements were certified by the State Housing and Community Development Department starting in 2022. The final adopted rezone sites will feed into CDR’s 2026 Orange County Projections.

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Table 4.8 Future Model Parameters
Data Category Variable Source Assumptions
Driver Units Single-family and
multifamily accounts
CDR Historical households per account; averages are
multiplied by households projected by CDR
Irrigation accounts Agency Billing Data Accounts are assumed to be constant into the future Sectoral Employment CDR Proportion of jobs within CII sectors projected by CDR
Explanatory
Variables
Monthly Maximum
Temperature and Total
Precipitation
PRISM 30-year historical normal weather
Water Price Retail Agencies Prices increase by 3% per year above inflation for 2025-2030 and keeps pace with inflation thereafter
(zero difference from inflation trend)
Water Use Restrictions State and Local
Restrictions
None
Seasonality Sine/cosine functions to capture monthly pattern Median Income US Census Constant income at 2022 value (real dollars) Housing Density CDR Derived from CDR housing unit projections, assuming residential area remains at 2024 levels
Persons Per Household CDR CDR projected demographics
Gross Domestic Product Federal Reserve Long-term GDP trend Relative Sectoral
Employment
CDR Calculated based on CDR projections
Passive Efficiency
Estimates
Flume Insight Assumes a 2% decrease in residential demand due to conservation by 2030 (linearly extrapolated), then
no change
COVID Binary Indicator None (occurred between March 2020 and May 2023) The normal year scenario was provided by the baseline forecast. In this model, the single dry year scenario used a hot-dry index (HDI) to identify the year with the most weather-sensitive demand, with 2014 selected for most agencies. The multiple dry year was developed to describe the potential impact of consecutive dry years.

The forecasts for individual agencies, including the City’s, was then summed to the regional level, providing regionally consistent forecasts for all of Orange County.

4.4 Water Loss
The City has conducted annual water loss audits since 2015 per the AWWA (American Water Works Association) methodology per SB 555 to understand the relationship between water loss, operating costs and revenue losses. Non-revenue water for Calendar Year (CY) 2020-2024 consists of three components:
real losses (e.g., leakage in mains and service lines, and storage tank overflows), apparent losses (unauthorized consumption, customer metering inaccuracies and systematic data handling errors), and unbilled water (e.g. hydrant flushing, firefighting, and blow-off water from well start-ups). Table 4.9 summarizes the status of the last five years of water loss audit reporting for the water system. Reports can be found online at WUEdata - Water Audit Plans. Understanding and controlling water loss from a

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distribution system is an effective way for the City to achieve regulatory standards and manage their existing resources.

Table 4.9 Submittal Table 4-5 Retail: Water Loss Audit Reporting Submittal Table 4-5 Retail: Water Loss Audit Reporting
Water Code Section 10631(d)(3)(A)
Public Water System ID # Reported in Table 2-1 R Reporting Period Submitted to DWR Water Loss Audit Program (yes/no)
Report submittal status for all five years for each Public Water System as available.

Add rows as needed
CA3010100
2020 Yes
2021 Yes
2022 Yes
2023 Yes
2024 Yes
DWR NOTES: Suppliers will provide a link to the WUEdata submittals of their Water Loss Audit Reports.

NOTES: Water Loss Audits reported in Calendar Years (CY).

Signed in 2018 and adopted in 2024, the “Making Conservation a California Way of Life” legislation (SB 606 and Assembly Bill 1668) establishes a new framework for long-term improvements in urban water use efficiency and drought planning as California adapts to climate change impacts. Under the regulation, Suppliers must annually calculate Urban Water Use Objectives based on standards applied at the service-area scale, including the Water Loss Performance Standard developed by the State Water Resources Control Board to minimize water waste through system leaks. The Water Loss Performance Standard requires that Suppliers must meet the real water loss standard and apparent water loss standard by 2028.

Table 4.10 presents the City’s progress towards compliance with the 2028 Water Loss Standard, as of the time of writing this UWMP. The most recent American Water Works Association (AWWA) Water Loss Audit for CY 2024 was utilized for the calculations presented.

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Table 4.10 Submittal Table 4-6 Retail: Progress Towards 2028 Water Loss Standard Submittal Table 4-6 Retail: Progress Towards 2028 Water Loss Standard Water Code Section 10631(d)(3)(C)
Public
Water
System ID #
Reported in
Submittal
Table 2-1 R
Did the Water Board
Calculate a Water
Loss Standard for
this Public Water
System? (y/n)
If no, Supplier will
not complete this
row.

Real Water Loss Apparent Water Loss
State Water Board
Standard
Most Recent AWWA
Water Loss Audit
Real
Water
Loss Per
Unit per
Day
State Water Board
Standard
Most Recent AWWA
Water Loss Audit
Apparen
t Water
Loss Per
Unit per
Day
2028 Real
Water Loss
Standard
per Unit
per day
Units for Real
Water Loss
Drop down
list
Number of
Units
(Connections or
Miles
corresponding
with units
selected)
Volume of
Total
Real Loss
(from
AWWA
Water
Loss
Audit)
2028
Apparent
Water Loss
Standard
per Unit per
Day
Units for
Apparent
Water Loss
Number of
Connections
Volume of
Total
Apparent
Loss
(from
AWWA
Water Loss
Audit)
(AF) (AF)
Add additional rows as needed.

CA3010100 Yes 17.9
Gallons per
Service
Connection
per Day
(GPSCD)
4,452 18.31 3.7 6.7
Gallons
per Service
Connection
per Day
(GPSCD)
4,452 29.25 5.9
Water Board's Calculated Water Loss Standards
DWR NOTES: Units of measure (AF, CCF, MG) for Water Loss MUST remain consistent with units reported in Submittal Table 2-3. The units reported in Submittal Table 2-3 are used in this table's calculations.

NOTES: Uses the Water Board’s calculated water loss standards updated as of 01/30/2026 and AWWA Water Loss Audit for CY 2024. Connection count may differ from what is reported in Table 2-1 R for FY 2025.

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CHAPTER 5 CONSERVATION TARGET COMPLIANCE
The Water Conservation Act of 2009, also known as Senate Bill (SB) X7-7, mandated a 20 percent reduction in urban per-capita water use across California by 2020. To achieve this goal, the Act required each retail water supplier to establish an urban water-use target, contributing to the State’s collective efforts. The Legislature stated that the combined reductions from all retail suppliers would fulfill the statewide legislative mandate.

The goal of this chapter is to allow the retail water supplier to report on their progress toward meeting their urban water-use targets in their UWMP, pursuant to Water Code Section 10608.40. Suppliers that did not meet their 2020 target in 2020 are required to compare their 2025 water use to the 2020 target.

Retail water suppliers are required to comply with SB X7-7 individually or as a region in collaboration with other retail water suppliers or demonstrate they have a plan or have secured funding to be in compliance, in order to be eligible for water related state grants and loans.

When determining water use in an UWMP, two terms are often used interchangeably:
 Daily Per-Capita Water Use. The amount of water used per person per day. In the UWMP calculations, this is total water use within a service area, divided by population, and it is measured in gallons.
 Gallons Per-Capita Per Day (gpcd). This is the “daily per-capita water use” measured in gallons.

Therefore, the term commonly used when referring to “daily per-capita water use” is “gallons per-capita per day” or gpcd1.

5.1 Reporting Requirements
MWDOC’s Water Use Efficiency (WUE) programs helped Orange County meet the state’s 20x2020 mandate by coordinating conservation efforts across its member agencies, funding and implementing regionally cost-effective efficiency programs, and enabling compliance through the Orange County 20x2020 Regional Alliance. By aligning its WUE portfolio directly with SB X7-7 requirements, supporting high-impact measures (especially outdoor water savings), documenting eligible indirect potable reuse credits, and centrally handling regional target calculations and reporting, MWDOC allowed participating retailers to comply collectively rather than individually resulting in regional per-capita water use well below the required 2020 target.
1 It is important to distinguish gpcd (as used in UWMPs) from the Residential Gallons Per Capita Per Day (R-gpcd) that is used in some reporting to the California State Water Resources Control Board (SWRCB). gpcd is the total water use from all sectors within a service area (residential, commercial, institutional, and any others) minus allowable exclusions (as defined in SB X7-7), then divided by the population. This is used in UWMPs. R-gpcd is only a part of the gpcd; it is the estimated residential water use in a service area divided by population.

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As a result of MWDOC’s WUE program, all Orange County water retailers, including all MWDOC’s member agencies and the participating cities of Anaheim, Fullerton, and Santa Ana, achieved compliance prior to 2020. The following table with information taken from the 2020 UWMP verifies that City of La Palma met their SB X7-7 requirement. A discussion of programs implemented to support the achievement of the agency’s per capita water reduction goals is covered in Chapter 9 – Demand Management Measures of this UWMP.

Table 5.1 Submittal Table 5-1 Retail: SB X7-7 2020 Target Progress Actual 2025 GPCD
(From SB X7-7
Compliance Form)
Did Supplier meet
the 2020 Target in
2025?
No Individual Target 129 75 Yes NA
Submittal Table 5-1 Retail: SB X7-7 2020 Target Progress Water Code Section 10608.40
NOTES: Supplier met the 2020 target, actual 2025 GPCD not required.

Did Supplier
Achieve Targeted
Reduction for
2020?
2020 Target Actual 2020 GPCD
Regional Alliance
Target or
Individual
Target?
Drop down list
DWR NOTES:

Suppliers calculating a 2025 GPCD will need to complete and submit SB X 7-7 Compliance Tables to verify the use of SB X7-7 Methodologies.

Suppliers that were part of a merger or consolidation since 2020 see Chapter 5 and Appendix P for guidance.

NA=Not Applicable
Check the box if the Supplier was not an Urban Water Supplier during or before the 2020 UWMP reporting cycle.

Proceed to the next table.

Only for suppliers that did not meet the
Target in 2020
See DWR NOTES below. Was Supplier part of
a merger or
consolidation since
2020?

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CHAPTER 6 WATER SUPPLY CHARACTERIZATION
Orange County has a water supply portfolio made up of a variety of local and imported sources.

Groundwater is produced from the Orange County Groundwater Basin (OC Basin), which is managed by the Orange County Water District (OCWD). To enhance the reliability of groundwater, OCWD has implemented projects and programs over the years that include: (1) the Groundwater Replenishment System (GWRS), which is the world's largest water purification system for indirect potable reuse; (2) increased stormwater capture for groundwater recharge; and (3) participation in the Santa Ana River Conservation and Conjunctive Use Program (SARCCUP), a collaborative, watershed-scale approach for groundwater basin management, replenishment, and water transfers.

Imported water that is provided by the Municipal Water District of Orange County (MWDOC) to Orange County retail water providers is purchased from the Metropolitan Water District of Southern California (MET), the wholesale water provider to 26 member agencies, of which MWDOC is one. MET's imported water sources are delivered through its own Colorado River Aqueduct (CRA) and the California Aqueduct, under contract with the State Water Project (SWP). To enhance its reliability of its imported water, MET has implemented many programs such as canal lining and transfers of agricultural water, land fallowing programs with irrigation districts, water banking programs, and use of its storage reservoirs. Groundwater from the Main San Gabrial Groundwater Basin (Main Basin) is also imported into the northern part of Orange County.

Local and imported water sources in Orange County are managed in such a way that they complement each other. For example, during wet and normal years, additional MET water is purchased for groundwater replenishment in the Orange County Basin. During dry and drought years, when imported water is more limited, more groundwater can be produced to meet Orange County's water demands. This coordinated management of water supplies has resulted in reliable water service even during multi-year droughts. Based on the water supply assessment described in this chapter and in Chapter 7, the Orange County region will continue to receive a reliable water supply through the next 25 years.

Specifically, this chapter includes: (1) descriptions of each water supply source and its management; (2) quantification of water supply sources through 2050 under normal, dry, and multi-dry weather conditions; (3) opportunities for exchanges and transfers; and (4) discussion regarding any planned or potential future water supply projects. This chapter also includes the energy intensity of the water service.

6.1 Water Supply Overview
Water supplies within the City's service area are from local and imported sources. Within Orange County, MWDOC is the wholesaler of imported water purchased from MET. Local retail agencies and one local wholesale agency in Orange County purchase imported water through MWDOC to supplement their local supplies. In FY 2024-25, MWDOC supplied approximately 123,571 acre-feet per year (AFY) of treated and untreated imported water to its retail agencies for M&I purposes and 91 AFY for MET Irvine Lake Replenishment. In FY 2024-25, imported water represented 31 percent of the total water supply in the MWDOC service area. However, imported water volume varies year to year; over the last 10 years, it has represented approximately 30 percent of the total M&I water supply for MWDOC.

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Local sources presently account for 97 percent of the City's water supplies, whereby groundwater is the major source of local supply. The primary source of groundwater originates from the OC Basin, which is located in the middle portion of MWDOC's service area and is managed by the Orange County Water District (OCWD). The Orange County Groundwater Replenishment System (GWRS) is a joint project between OCWD and the Orange County Sanitation District (OC San). Using advanced treatment, recycled wastewater is transformed into a high-quality water supply for groundwater replenishment.

The City's main source of water supply is groundwater from the OC Basin. Imported water makes up the rest of the City's water supply portfolio. In FY 2024-25, the City relied on approximately 97 percent groundwater and 3 percent imported water (Table 6.1).

Table 6.1 Submittal Table 6-8 Retail: Water Supplies - 2025 Actual Submittal Table 6-8 Retail: Water Supplies — 2025 Actual Water Code Section 10631(b)
Water Supply Additional Description
2025
Actual Volume
(AF)
Groundwater (not desalinated) Orange County Groundwater Basin 1,622 Purchased or Imported Water MWDOC 48
Total 1,670
NOTES: Source - City of La Palma, 2026
In 2025, MWDOC developed a water demand forecast model for its participating water agencies that statistically correlates municipal and industrial (M&I) water use with demographic, socioeconomic, conservation, and weather variables—as reported in the 2025 Orange County Water Demand Projection Model TM (MWDOC, 2025). Because the model isolates weather, future water demand projects can be estimated under single and multiple-year droughts and under future climate change scenarios.

It is projected that by 2050, the City's water portfolio will change to approximately 85 percent groundwater and 15 percentimported water (Table 6.2 and Figure 6.1). It should be noted that these representations of supply match the projected demand. However, the City can purchase more MET imported water through MWDOC, should the need arise. Note that the Groundwater Replenishment System (GWRS) supplies are included as part of groundwater pumping numbers.

The following subsections provide a detailed discussion of the City's water sources as well as the future water supply portfolio for the next 25 years.

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Figure 6.1 City's Projected Water Supply

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Table 6.2 Submittal Table 6-9 Retail: Water Supplies - Projected Submittal Table 6-9 Retail: Water Supplies — Projected
Water Code Section 10631 (b)
Water Supply Additional Detail on
Water Supply
Projected Water Supply (Report to the Extent Practicable) 2030 2035 2040 2045 2050
Reasonably
Available Volume
Reasonably
Available Volume
Reasonably
Available Volume
Reasonably
Available Volume
Reasonably
Available Volume
(AF) (AF) (AF) (AF) (AF)
Purchased or Imported Water MWDOC 256 257 258 258 258
Groundwater (not desalinated) OC Basin 1,449 1,455 1,464 1,463 1,462 Total 1,705 1,711 1,722 1,721 1,721
NOTES: Source - MWDOC, 2025.

Groundwater volumes assume OCWD's basin production percentage (BPP) to be 85 percent starting in 2025. Volumes of groundwater and imported water may vary depending on OCWD's actual BPP projections, which are established annually.

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6.2 Imported Water
The City supplements its water supply with imported water purchased from MET through MWDOC. In Fiscal Year (FY) 2024-25, the City relied on approximately 1,610 AFY—approximately 97 percent of the City's water supply portfolio for FY 2024-25—of imported water from MET/MWDOC to meet its demands.

MET's two principal sources of water are the Colorado River and the SWP. MET receives water from the Colorado River through the CRA and from the SWP through the California Aqueduct. For Orange County, the water obtained from these sources is treated at the Robert B. Diemer Filtration Plant located in the City of Yorba Linda. Typically, the Diemer Filtration Plant receives a blend of Colorado River water from Lake Mathews through the MET Lower Feeder and SWP water through the Yorba Linda Feeder.

6.2.1 Metropolitan Water District of Southern California MET is the largest water wholesaler in California, serving approximately 19 million customers in a 5,200 square mile (sq mi) service area. MET wholesales imported water supplies to 26 member agencies located in the six southern California counties of Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Ventura.

MET is governed by a Board of Directors comprised of 38 appointed individuals with a minimum of one representative from each of MET's 26 member agencies. The allocation of directors and voting rights is determined by each agency's assessed valuation. Each member of the Board is entitled to cast one vote for each ten million dollars of assessed valuation of property taxable for district purposes, in accordance with Section 55 of the Metropolitan Water District Act. Directors may be appointed by the chief executive officer of the member agency or by a majority vote of the agency's governing board. Directors are not compensated by MET for their service (The Metropolitan Water District Act, 1969).

MET is responsible for importing water into the region through its operation of the CRA, which brings Colorado River supply to its service area, and its SWP contract, which brings water from northern California via the California Aqueduct. MET supplements its direct deliveries of imported supplies with its storage reservoirs, water transfers, agricultural irrigation water conservation, and water banking programs.

Major imported water aqueducts bringing water to Southern California are shown in Figure 6.2. It should be noted that the Los Angeles Aqueduct is owned and operated by the Los Angeles Department of Water and Power and is not part of MET's imported water supplies.

Member agencies receive water from MET through various delivery points and pay for service through a rate structure comprising volumetric rates, capacity charges, and readiness-to-serve charges. Member agencies provide MET with estimates of imported water demand in April each year, indicating the amount of water they anticipate they will need to meet their demands over the next five years.

In Orange County, MWDOC and the cities of Anaheim, Fullerton, and Santa Ana are MET member agencies that purchase imported water directly from MET. MWDOC purchases both treated potable and untreated water from MET to supplement its retail agencies' local water supplies and for groundwater replenishment. Figure 6.3 illustrates the MET feeders and major transmission pipelines that deliver water within Orange County.

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Figure 6.2 Major Aqueducts that Supply Imported Water to Southern California (MET, 2025)

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Figure 6.3 MET Feeders and Transmission Mains that Serve Orange County

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6.2.2 Colorado River Aqueduct

6.2.2.1 Background
The Colorado River was MET's original source of water after MET's establishment in 1928. The original founding members created MET with the goal to build the CRA to bring water to Southern California. The CRA, which is owned and operated by MET, transports water from the Colorado River to its terminus, Lake Mathews, in Riverside County. The actual amount of water per year that may be conveyed through the CRA to MET's member agencies is subject to the availability of Colorado River water. Approximately 40 million people rely on the Colorado River and its tributaries for potable water, with 5.5 million acres of land using Colorado River water for irrigation. The CRA includes supplies from the implementation of the Quantification Settlement Agreement (QSA) and its related agreements to transfer water from agricultural agencies to urban uses. The 2003 QSA enabled California to implement major Colorado River water conservation and transfer programs to stabilize water supplies and reduce the state's demand on the river to its 4.4 million acre-feet (MAF) entitlement. Colorado River transactions are potentially available to supply additional water up to the CRA capacity of 1.25 MAF on an as-needed basis. Water from the Colorado River or its tributaries is available to users in California, Arizona, Colorado, Nevada, New Mexico, Utah, Wyoming, and Mexico. California is apportioned the use of 4.4 MAF of water from the Colorado River each year, plus one-half of any surplus that may be available for use collectively in Arizona, California, and Nevada. In addition, California has historically been allowed to use Colorado River water apportioned to, but not used by, Arizona or Nevada. MET has fourth-priority rights, with a basic entitlement of 550,000 AFY of Colorado River water, plus surplus water up to an additional 662,000 AFY when the following conditions exist (MET, 2025):
 Water is unused by the California holders of priorities 1 through 3.  Water is saved by the Palo Verde land management, crop rotation, and water supply program.  When the US Secretary of the Interior makes available either one or both of the following:
» Surplus water.
» Colorado River water that is apportioned to but unused by Arizona and/or Nevada.

6.2.2.2 Current Conditions and Supply
The Colorado River supply faces current and future imbalances between water supply and demand in the Colorado River Basin due to reductions in snowpack, long-term drought conditions, and climate change.

The last 25-year period has been called a megadrought, with Lake Mead's elevation dropping from a high of 1,215 feet in 2000 to its lowest level of 1,040 feet in July 2022. While extreme wet conditions resulted in lake levels exceeding 1,077 feet in February 2024, levels have been persistently hovering around 1,057 feet since May 2025. The United States Bureau of Reclamation (USBR) projects that there is a 53 percent likelihood that Lake Mead elevation could fall below 1,035 feet, which would trigger water shortages for MET under the current operating guidelines. As of August 2025, Lake Mead storage was approximately 31 percent of capacity per USBR's 24-Month Study, which also projected continued Lower Basin shortage conditions in 2026 (MET, 2025).

The current operating guidelines for the Colorado River expire at the end of 2026, and a new, long-term operating plan must be in place by November 2026 to manage the river's water supply. The ongoing Colorado River allocation negotiations are focused on creating a post-2026 operating plan, with states

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and the federal government aiming for consensus on how to manage the river's declining water supply due to the severe, prolonged drought in the Colorado River Basin. The drought on the Colorado River began around 2000 and has continued, in various degrees of severity, for over two decades, making it a historic megadrought that has significantly reduced water flow into the river and lowered water levels in reservoirs like Lake Powell and Lake Mead. Although some periods, like the wet winter of 2023, brought temporary relief with increased snowfall, they were not enough to fully replenish the system or overcome the prolonged lack of water and effects of climate change, such as aridification and increased evaporation, according to the US Geological Survey (USGS, 2024). Under the 2007 Interim Guidelines, together with the Lower Basin Drought Contingency Plan (2019), the Intentionally Created Surplus (ICS) program has allowed MET to store conserved water in Lake Mead for subsequent recovery; these frameworks sunset with the Guidelines at the end of 2026 and are expected to be addressed in the post-2026 rules (MET, 2025).

The USBR, which is part of the U.S. Department of the Interior, is the federal agency leading the negotiations and responsible for managing the river system. The ongoing Colorado River negotiations aim to find a fair and sustainable way to allocate the available water, which is significantly less than in the past. Talks are centering on a "natural flow" proposal that divides water based on current river conditions, rather than historical allocations. However, states remain at odds over how much water to allocate to the Upper and Lower Basins, with the federal government planning to impose its own plan if an agreement is not reached by the November 2026 deadline. Some key challenges that remain to be resolved are the different interests of the Upper Basin states (Colorado, Utah, Wyoming, New Mexico) and the Lower Basin states (California, Arizona, Nevada) to reach consensus on how much water the Upper Basin should send downstream. In addition, Tribal nations are also seeking recognition of their rights and a role in the future management of the river. Given MET's junior priority status within California's Colorado River priority system, reductions to MET's supplies are a possibility under future operating criteria; MET's planning reflects this risk (MET, 2025).

Consistent with MET's 2025 UWMP, supply capability planning uses USBR's August 2023 Colorado River Simulation System (CRSS) assumptions, including a climate-adjusted flow reduction factor of approximately 9.3 percent per 1 degree Celsius (°C) of warming over the planning horizon (2025–2050).

MET continues to utilize supply, storage, transfer, and conservation programs, including ICS participation under the current Guidelines, to manage risk and buffer shortages. In addition, conserved QSA-related transfer water delivered at Lake Havasu (including Imperial Irrigation District and canal-lining exchanges) is categorized in MET's 2025 UWMP as Colorado River imported supply (previously treated as local supply), aligning accounting with current practice (MET, 2025).

6.2.2.3 MET Colorado River Current Programs
Over the years, MET has helped fund and implement various programs to improve Colorado River supply reliability and help resolve the imbalance between supply and demand. Implementation of such programs has contributed to achievements such as a record-low diversion of the Colorado River in 2019, a level not seen since the 1950s. Colorado River water management programs include:
 Lower Colorado Water Supply Projects - Authorized in the 1980s, this project provides up to 10,000 AFY of water to certain entities that do not have or have insufficient rights to use Colorado River water. A contract executed in 2007 allowed MET to receive project water left unused by the

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project contractors along the River—nearly 10,000 acre-feet (AF) were received in recent years when unused supplies were available.
 Imperial Irrigation District / MET Conservation Program - Under agreements executed in 1988 and 1989, this program allows MET to fund water efficiency improvements within Imperial Irrigation District's service area in return for the right to divert the water conserved by those investments. An average of 105,000 AFY of water has been conserved since the program's implementation.  Management of MET-Owned Land in Palo Verde - Since 2001, MET has acquired approximately 21,000 acres of irrigable farmland that are leased to growers, with incentives to grow low water-using crops and experiment with low water-consumption practices. MET continues to evaluate opportunities to formally account for verified long-term water savings associated with these lands as part of its Colorado River supply reliability strategy.
 Palo Verde Land Management, Crop Rotation, and Water Supply Program - Authorized in 2004, this 35-year program allows MET to pay participating farmers to reduce their water use, and for MET to receive the saved water. Over the life of the program, an average of 84,500 AFY has been saved and made available to MET.
 Southern Nevada Water Authority (SNWA) and MET Storage and Interstate Release Agreement - Entered in 2004, this agreement allows SNWA to store its unused, conserved water with MET, in exchange for MET to receive additional Colorado River water supply. MET has relied on the additional water during dry years, especially during the 2011-2016 California drought, and SNWA is not expected to call upon MET to return water until after 2026.  Lake Mead Storage Program - Executed in 2006 and subsequently integrated with Lower Basin Drought Contingency Plan (DCP) operations, MET may intentionally leave conserved water in Lake Mead for exclusive future use. MET has significantly expanded its use of intentionally created surplus (ICS) storage in recent years, including record storage creation (450,000 AF) in 2023 under DCP‑related conservation programs.
 Quagga Mussel Control Program - Developed in 2007, this program introduced surveillance activities and control measures to combat quagga mussels, an invasive species that impacts the Colorado River's water quality.
 Bard Seasonal Fallowing Program - Authorized in 2019 and subsequently expanded, this program allows MET to pay participating farmers in Bard to reduce their water use between the late spring and summer months of selected years. Under expanded program authorizations through 2026 (Quechan Seasonal Fallowing Program), this program can provide up to approximately 12,000 AFY in certain years.
 Lower Basin Drought Contingency Plan - Signed in 2019, this agreement incentivizes storage in Lake Mead through 2026, and overall, it increases MET's flexibility to fill the CRA as needed (MET, 2025).
 Lower Basin Conservation and System Efficiency Programs - In recent years, MET has participated in new, multi-agency conservation and system efficiency programs implemented between 2023 and 2026. These programs incentivize agricultural conservation, system efficiency improvements, urban conservation, and groundwater storage in the Lower Colorado River Basin, with the goal of reducing

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system demands and increasing storage in Lake Mead during critically dry conditions. This includes programs such as the Quechan Diversion Forbearance program.  Exchange Programs - MET is involved in separate exchange programs with the USBR, which takes place at the Colorado River Intake and with San Diego County Water Authority (SDCWA), which exchanges conserved Colorado River water.

The Colorado River faces long-term challenges of water demands exceeding available supply with additional uncertainties due to climate change. Climate change impacts expected in the Colorado River Basin include the following:
 More frequent, more intense, and longer-lasting droughts, which will result in water deficits.  Continued dryness in the Colorado River Basin, which will increase the likelihood of triggering a first-ever shortage in the Lower Basin.
 Increased temperatures, which will affect the percentage of precipitation that falls as rain or snow, as well as the amount and timing of mountain snowpack (MET, 2025).

Given these uncertainties, MET plans to continue implementing and expanding Colorado River conservation, storage, exchange, and transfer programs, while also supporting increased water recycling and system efficiency improvements within the Colorado River Basin. MET continues to evaluate additional transfer and conservation opportunities to further enhance regional supply reliability through the 2025 UWMP planning horizon.

6.2.3 State Water Project

6.2.3.1 Background
The SWP consists of a series of pump stations, reservoirs, aqueducts, tunnels, and power plants operated by the California Department of Water Resources (DWR) and is an integral part of the effort to ensure that business and industry, urban and suburban residents, and farmers throughout much of California have sufficient water. Water from the SWP originates at Lake Oroville, which is located on the Feather River in Northern California. Much of the SWP water supply passes through the Sacramento-San Joaquin Delta ("Delta"). The SWP is the largest state-built, multipurpose, user-financed water project in the United States. Nearly two-thirds of residents in California receive at least part of their water from the SWP, with approximately 70 percent of SWP's contracted water supply going to urban users and 30 percent to agricultural users. The primary purpose of the SWP is to divert and store water during wet periods in Northern and Central California and distribute it to areas of need in Northern California, the San Francisco Bay area, the San Joaquin Valley, the Central Coast, and Southern California (MET, 2025).

The Delta is key to the SWP's ability to deliver water to its agricultural and urban contractors. All but five of the 29 SWP contractors receive water deliveries below the Delta (pumped via the Harvey O. Banks or Barker Slough pumping plants). However, the Delta faces many challenges concerning its long-term sustainability, such as climate change posing a threat of increased variability in floods and droughts. Sea level rise complicates efforts in managing salinity levels and preserving water quality in the Delta to ensure a suitable water supply for urban and agricultural use. Furthermore, other challenges include continued subsidence of Delta islands, many of which are already below sea level, and the related threat of catastrophic levee failure as water pressure increases or following a major seismic event.

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In May 2019, DWR withdrew its permit for the two-tunnel WaterFix project in favor of a smaller one-tunnel project alternative. In July 2022, the draft Environmental Impact Report (EIR) for the recommended Delta Conveyance Project alternative was issued, with the project potentially operational by 2045 (Delta Conveyance Design and Construction Authority, 2024), though its implementation faces strong opposition by environmental organizations and other interests in the Delta. The maximum value of the Delta Conveyance Project, when coupled with 250,000 AF of new regional storage, is estimated to be 367,000 AFY for MET, with 63,000 AFY of that amount for Orange County. The Delta Conveyance Project also reduces the probability that any shortage occurs by about 10 percent, meaning a doubling of the time between shortage conditions from once every 5 years to once every decade (MWDOC, 2023).

6.2.3.2 Current Conditions and Supply
Just like the Colorado River, the amount of water that can be delivered from the SWP to its 29 contractors varies annually based on hydrology and reservoir storage along the SWP. The DWR publishes the maximum entitlement of SWP water for each water contracting agency in "Table A." DWR sets these allocations to balance the needs for human health and safety, agricultural, and municipal water, considering factors like reservoir storage, runoff forecasts, and Endangered Species Act (ESA) requirements. The primary drivers that influence allocations are hydrologic conditions (precipitation and snowmelt) along with storage levels, especially in Lake Oroville. Actual deliveries typically average less than 50 percent of Table A due to hydrologic and regulatory constraints (MET, 2025). MET's actual annual allocations based on springtime Table A values for the past UWMP cycles are summarized in Table 6.3.

Table 6.3 MET SWP Program Capabilities
Year Average Annual Table A Spring Allocation (MAF)
2015 0.38
2020 0.38
2025 0.96
Percent Change(1) +252.6%
Notes:

Source: SWP Allocations 1996-2026.
(1) Percent change is between the years 2020 and 2025.

SWP contractors may additionally receive Article 21 water on a short-term basis in addition to Table A water if requested. Article 21 of SWP contracts allows contractors to receive additional water deliveries only under specific conditions, generally during wet months of the year (December through March).

Because a SWP contractor must have an immediate use for Article 21 supply or a place to store it outside of the SWP, there are few contractors like MET that can access such supplies (MET, 2025).

Carryover water is SWP water allocated to an SWP contractor and approved for delivery to the contractor in a given year but not used by the end of the year. The unused water is stored in the SWP's share of San Luis Reservoir, when space is available, for the contractor to use in the following year (MET, 2025).

Turnback pool water is Table A water that has been allocated to SWP contractors who have exceeded their demands. This water can then be purchased by another contractor depending on its availability (MET, 2025).

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The following factors affect the ability to estimate existing and future water delivery reliability:
 Water availability at the source: Availability can be highly variable and depends on the amount and timing of rain and snow that fall in any given year. Generally, during a single dry year or two, surface and groundwater storage can supply most water deliveries, but multiple dry years can result in critically low water reserves. Fisheries issues can also restrict the operations of the export pumps even when water supplies are available.
 Water rights with priority over the SWP: Water users with prior water rights are assigned higher priority in DWR's modeling of the SWP's water delivery reliability, even ahead of SWP Table A water.  Climate change: Mean temperatures are predicted to vary more significantly than previously expected. This change in climate is anticipated to bring warmer winter storms that result in less snowfall at lower elevations, reducing total snowpack. From historical data, DWR projects that by 2050, the Sierra snowpack will be reduced from its historical average by 25 to 40 percent. Increased precipitation as rain could result in a larger number of "rain-on-snow" events, causing snow to melt earlier in the year and over fewer days than historically, affecting the availability of water for pumping by the SWP during summer. Furthermore, water quality may be adversely affected due to the anticipated increase in wildfires. Rising sea levels may result in potential pumping cutbacks on the SWP and CVP. DWR's recent planning documents and the Draft 2025 DCR describe climate-adjusted "existing conditions" baselines and future scenarios used by agencies for UWMPs.  Regulatory restrictions on SWP Delta exports: The Biological Opinions (BiOps) protect special-status species such as delta smelt and spring- and winter-run Chinook salmon and imposed substantial constraints on Delta water supply operations through requirements for Delta inflow and outflow and export pumping restrictions. Restrictions on SWP operations imposed by state and federal agencies contribute substantially to the challenge of accurately determining the SWP's water delivery reliability in any given year (DWR, 2020b).
 Ongoing environmental and policy planning efforts: Following the 2019 withdrawal of WaterFix, DWR certified the Delta Conveyance Project Final EIR and approved the Bethany alignment in December 2023, a key modernization initiative for the SWP. EcoRestore and related habitat efforts continue to advance.
 Delta levee failure: The levees are vulnerable to failure because most original levees were simply built with soils dredged from nearby channels and were not engineered. A breach of one or more levees and island flooding could affect Delta water quality and SWP operations for several months.

When islands are flooded, DWR may need to drastically decrease or even cease SWP Delta exports to evaluate damage caused by salinity in the Delta.

It can be concluded that the federal regulatory framework affecting the Bay-Delta's ecosystem, species, and water supply is constantly evolving by adapting to new scientific information, changing climate conditions, and legal challenges. This dynamic and complex regulatory landscape, along with hydrologic and storage conditions along the SWP, continues to result in water supply uncertainties that impact all SWP contractors, including MET, MWDOC, and its member agencies (MET, 2025).

6.2.3.3 SWP Programs/Plans
In the past five years, MET has updated and implemented planning, regulatory, infrastructure, and operational programs to improve the reliability of the SWP supplies while addressing environmental,

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seismic, and climate-related risks in the Sacramento-San Joaquin Delta and along the California Aqueduct.

Key SWP programs and planning efforts include:
 SWP Biological Opinions and California Incidental Take Permit - Updated federal Biological Opinions and a California ITP issued in 2024 provide a new operating framework intended to improve flexibility and species protection. The 2025 MET UWMP characterizes the net reliability benefit at approximately +60,000 AFY relative to prior permits, subject to hydrologic and regulatory conditions.  Healthy Rivers and Landscapes (HRL) Voluntary Agreements - MET supports the State's proposed Healthy Rivers and Landscapes program, which establishes a voluntary framework for improving Delta ecosystem conditions through coordinated flow contributions and habitat restoration projects. The HRL approach is intended to provide regulatory stability while supporting environmental objectives consistent with SWP operations.

6.2.4 Storage, Transfers, and Conveyance Programs
Storage is a major component of MET's dry year resource management strategy. MET's likelihood of having adequate supply capability to meet projected demands, without implementing its Water Supply Allocation Plan (WSAP), depends on its storage resources. Following a significant drawdown during the 2020–2022 drought, MET rebuilt storage as hydrologic conditions improved. By the end of 2023, MET had approximately 3.4 MAF of regional dry-year storage. Storage increased to 3.8 MAF by the end of 2024, with levels projected to reach approximately 3.9 MAF by the end of 2025. MET also maintains approximately 750 TAF of emergency storage dedicated to catastrophic supply interruption conditions, including a major seismic failure of the Delta levees.

In its 2025 UWMP, MET evaluates storage based on median starting storage at the beginning of each five-year increment, representing a 50 percent probability that actual storage will be higher or lower. This approach differs from earlier UWMPs, which relied on average storage assumptions, and provides a more conservative and realistic representation of storage availability. All storage capability values incorporate conveyance and recovery constraints associated with SWP terminal reservoirs, the CRA, and MET's in-region and out-of-region groundwater banking programs.

Lake Oroville continues to serve as the SWP's largest storage facility with a capacity of approximately

3.5 MAF. Water released from Oroville moves to the Feather River and then to the Sacramento River before being pumped south at the Harvey O. Banks pumping plant into the California Aqueduct. MET's storage portfolio includes surface reservoirs such as Diamond Valley Lake, Lake Mathews, and Lake Skinner; SWP terminal storage in San Luis Reservoir; groundwater banking programs including Semitropic, Arvin-Edison, the High Desert Water Bank, Kern Delta, and Mojave; and ICS storage in Lake Mead. These storage assets provide operational flexibility during dry years and help maintain supplies during extended droughts or emergency events.

MET endeavors to increase the reliability of water supplies through the development of flexible storage and transfer programs, including groundwater storage (MET, 2025). These include:
 Antelope Valley-East Kern (AVEK) Water Agency Exchange and Storage Program: Under the exchange program, for every 2 AF MET receives, MET returns 1 AF back to AVEK, and MET will also be able to store up to 30,000 AF in AVEK's groundwater basin, with a dry-year return capability of 10,000 AF.

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 Arvin-Edison Storage Program: The storage program is estimated to deliver 75,000 AF, and the specific amount of water MET can expect to store in and subsequently receive from the program depends on hydrologic conditions and any regulatory requirements restricting MET's ability to export water for storage. During wet years, MET has the discretion to use to program to store portions of its SWP supplies which are in excess, and during dry years, the Arvin-Edison Water Storage District returns MET's previously stored water to MET by direct groundwater pump-in or by exchange of surface water supplies.
 Diamond Valley Lake to Rialto Pipeline - Planned for completion in 2028, this project creates new conveyance that improves the ability to move non-SWP supplies (120 cubic feet per second [cfs], including CRA and banked water) into areas historically dependent on SWP deliveries, increasing drought and seismic resilience.
 High Desert Water Bank Program: Developed in partnership with Antelope Valley–East Kern Water Agency, this regional groundwater banking program allows MET to store up to 280,000 AF of SWP Table A or other available supplies in the Antelope Valley groundwater basin. The program provides a put-and-take capability of up to approximately 70,000 AF per year, with infrastructure including monitoring and production wells, California Aqueduct turnouts, pipelines, recharge basins, and pump facilities. Phase 1 became operational in 2023, with full build-out expected by approximately 2030.  Kern-Delta Water District Storage Program: This groundwater storage program has 250,000 AF of storage capacity, and water for storage can either be directly recharged into the groundwater basin or delivered to Kern-Delta Water District farmers in lieu of pumping groundwater. During dry years, the Kern-Delta Water District returns MET's previously stored water to MET by direct groundwater pump-in return or by exchange of surface water supplies.  Mojave Storage Program: MET entered into a groundwater banking and exchange transfer agreement with Mojave Water Agency that allows for the cumulative storage of up to 390,000 AF. The agreement allows for MET to store water in an exchange account for later return.  Richvale & Western Canal Water Transfers - These multi-year transfer options will provide supplemental dry-year supplies when available, with volumes up to approximately 54,000 AF (2025-2027).
 San Bernardino Valley MWD Surplus SWP Program - Programmatic access to surplus SWP supplies (approximately 13 TAF) will be available from SBVMWD under certain hydrologic and operational conditions.
 Semitropic Storage Program: The maximum storage capacity of the program is 350,000 AF, and the minimum and maximum annual yields available to MET are 34,700 AF and 236,200 AF, respectively.

The specific amount of water MET can expect to store in and subsequently receive from the program depends on hydrologic conditions, any regulatory requirements restricting MET's ability to export water for storage and demands placed by other program participants. During wet years, MET has the discretion to use the program to store portions of its SWP supplies which are in excess, and during dry years, the Semitropic Water Storage District returns MET's previously stored water to MET by direct groundwater pump-in or by exchange of surface water supplies.

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 Sepulveda Feeder Pump Stations (Stage 1) - This program includes pumping improvements that expand westward movement of CRA/SWP/banked supplies across service areas to address localized system constraints. Pumping capacity is expected to be 30 cfs upon completion of Stage 1 in 2027.  Yuba Accord Extension - This project is a continuation of an established dry-year transfer program from the Yuba watershed that can be accessed subject to hydrologic and regulatory conditions. As of 2025, the extension is under negotiation for approximately 250,000 AFY in supply.

6.2.5 Potential Future Water Projects

6.2.5.1 Climate Adaptation Master Plan for Water
In February 2023, the MET's Board directed its staff to integrate water resources planning, climate resilience planning, and financial planning into a Climate Adaptation Master Plan for Water (CAMP4W).

Then a Joint Task Force of Board Members and Member Agency Managers was convened to facilitate the development of CAMP4W in a timely and transparent process. The main elements of CAMP4W include:

1. Identify climate and growth scenarios, building from analyses conducted for MET's Integrated Resources Plan (IRP);

2. Develop time-bound targets for new regional water supplies and system improvements;

3. Establish a framework for decision-making and annual reporting;

4. Form policies, initiatives, and partnerships; and

5. Evaluate business models and funding strategies
Because investments required for regional supply reliability and system resilience are significant, it is important that decisions are made through an adaptive management process to avoid the risks associated with over-investment or under-performance. Tracking signposts and progress towards time-bound targets is therefore critical for CAMP4's annual reporting. Currently, regional projects being explored by MET include Pure Water Southern California, new reservoir storage in Southern California of up to 155,000 AFY, regional seawater desalination, and participation in California's Delta Conveyance Project.

These projects will be scored against the following CAMP4W criteria: (1) reliability; (2) resilience; (3) financial; (4) adaptability/flexibility; (5) equity; and (6) environmental co-benefits.

Pure Water Southern California - The potential Pure Water Southern California program, a partnership with the Sanitation Districts of Los Angeles County, would purify wastewater treatment effluent that currently flows to the ocean to produce high-quality recycled water. The purified water would be delivered to Metropolitan's member agencies to meet their groundwater replenishment and storage requirements. It should be noted that the 2025 MET UWMP does not include Pure Water yield in projected supplies (MET, 2025).

Sites Reservoir - This potential project includes a water storage reservoir of 1.5 MAF and would require the construction of two large dams up to 310 feet high and nine smaller saddle dams. The water stored in the reservoir, located north of Sacramento, would be diverted from the Sacramento River during high flow events and returned to the Sacramento River during dry and critical years, thereby providing additional dry-year water for environmental flows and project partners including SWP agencies south of the Delta.

The current operations model estimates the annual water yield of the Sites Reservoir Project at approximately 270 TAF per year by 2032, when the Sites Reservoir Project is scheduled to be operational

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(MET, 2025). It should be noted that the 2025 MET UWMP does not include Sites Reservoir in projected supplies (MET, 2025).

Delta Conveyance Project (DCP) Following DWR's withdrawal and subsequent termination of the California WaterFix project, the State advanced a new single-tunnel Delta Conveyance Project to address seismic risk, sea-level rise, extreme weather, and regulatory uncertainty while improving long-term SWP delivery reliability. The environmental review was completed in 2023 and DWR has approved the project.

Potential yield used in planning analyses is on the order of approximately 400,000 AFY. It should be noted that the 2025 MET UWMP does not include Delta Conveyance Project yield in projected supplies pending future milestones and contracting decisions (MET, 2025).

6.2.6 Supply Reliability Within MET

6.2.6.1 MET's Water Service Reliability Assessment Results In MET's 2025 UWMP, MET evaluated supply reliability by projecting supply and demand under a normal year, single-dry year, and five-year consecutive dry years, based on conditions affecting the SWP (MET's largest and most variable supply). For this supply source, the average of 100 historical years 1922-2021 most closely represents water supply conditions in a normal water year, the single driest year was 1977 and the five-year dry period was 1988-1992. The analyses also include Colorado River supplies under the same hydrological variations.

MET also incorporated the SWP and Colorado River's reliability factors, such as water quality objectives set by the SWRCB, BiOps, and amendments to the Coordinated Operations Agreement for the SWP and Quantification Settlement Agreements for the Colorado River into their assessment.

MET has concluded that the region can provide reliable water supplies under normal, single-dry, and five-year consecutive dry conditions as presented in Table 6.4, Table 6.5, Table 6.6, respectively.

In each of the following tables, "Current Programs" supplies include:
 In-Region Supplies and Programs
» Metropolitan Surface Storage (Diamond Valley Lake, Lake Mathews, Lake Skinner) » Flexible Storage in Castaic Lake and Perris Lake
» Groundwater Storage for Conjunctive Use
 California Aqueduct (SWP), including Central Valley transfers and storage program supplies conveyed by the aqueduct
 Colorado River Aqueduct, including deliveries, programs, and exchanges with SDCWA These supplies are impacted - typically reduced - by the single dry year and multiple dry year scenarios.

Though demands increase in these drought conditions, MET projects reliable supply, even surplus, through 2050. MWDOC is a MET member agency, and MET's projections take into account the imported demands from Orange County. As so, MET's water reliability assessments are used to determine that demands within MWDOC can be met for all three hydrological conditions.

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Table 6.4 MET's Projected Supply Capability and Demands through 2050 for a Normal Year

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Table 6.5 MET's Projected Supply Capability and Demands through 2050 for a Single Dry Year

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Table 6.6 MET's Projected Supply Capability and Demands through 2050 for a Drought (5 Consecutive Water Years)

6.2.6.2 MET's Drought Risk Assessment Results
For its Drought Risk Assessment (DRA), MET assessed the reliability of each individual water supply source over the five-consecutive-year drought through a modeling method using the same historical hydrologic conditions as the water service reliability assessment: 1922 to 2021. MET used the five consecutive years of 1988 to 1992 to complete its DRA, because this represents the driest five-consecutive year historical sequence for MET's supply. As shown in Table 6.7, MET's total supplies are insufficient to fully meet projected demands under these drought conditions, resulting in annual shortfalls in four of the five years and a cumulative deficit of approximately 1.1 MAF by FY 2029–30. These results indicate that MET's SWP and CRA supplies alone cannot meet demands during this five‑year drought period without additional

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actions. MET's 2025 UWMP therefore identifies Water Shortage Contingency Plan (WSCP) actions, as necessary tools to close the deficit and maintain service through the modeled drought sequence (Table 6.7).

Table 6.7 MET's Water Use, Supply, and Drought Risk Assessment for 2026-2030

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6.3 Local Groundwater
Among all local supplies available to the City's service area, groundwater supplies make up the majority, with the primary supply from the OC Basin. The water supply resources within the City's service area are enhanced by the existence of groundwater basins, which provide a reliable local source and, additionally, are used as reservoirs to store water during wet years and draw from storage during dry years. Table 6.8 shows a breakdown of historical groundwater production by the City.

Table 6.8 Submittal Table 6-1 Retail: Groundwater Pumped in the Past 5 Years Within the City's Service Area Submittal Table 6-1 Retail: Groundwater Volume Pumped
Water Code Section 10631(4) and 10631(4)(c)
Groundwater
Type
Water Type (Potable/
Non-Potable)
(optional)
Location or Basin
Name
2021 2022 2023 2024 2025
(AF) (AF) (AF) (AF) (AF)
Alluvial Basin Orange County
Groundwater Basin
1,990 1,705 1,610 1,605 1,622
Total 1,990 1,705 1,610 1,605 1,622
NOTES: Source - MWDOC, 2025
The City pumps groundwater through two operating wells: Meadowlark (City Yard) Well and Walker Street Well. Meadowlark is located in the south side of the City. The well has a rated capacity of 1,800 gpm but typically operates at approximately 1,700 gpm. The Walker Street well is located on the north side of the City. The well has a rated capacity of 1,500 gpm, but due to excessive sand and gravel production, the current flow capacity of the well is decreased to approximately 1,000 gpm. Current total well production is approximately 2,700 gpm, which is reduced from original total design rating of 3,300 gpm, but rehabilitation project to Walker Street Well is expected to increase the City's total groundwater production capacity (Infrastructure Engineers, 2020).

This section describes the groundwater basin used by the City and provides a 25-year projection of the service area's groundwater supply.

6.3.1 Orange County Groundwater Basin
This section describes the OC Basin and the management measures taken by OCWD, the basin manager and member agency of MWDOC, to optimize local supply and minimize overdraft.

The OCWD was formed in 1933 by a special legislative act of the California State Legislature to protect and manage the County's vast, natural, groundwater supply using the best available technology and defend its water rights to the OC Basin. This legislation is found in the State of California Statutes, Water - Uncodified Acts, Act 5683, as amended. The OC Basin is managed by OCWD under the Act, which functions as a statutorily-imposed physical solution. The OCWD Management Area includes approximately 89 percent of the land area of the OC Basin, and 98 percent of all groundwater production occurs within the area. Approximately 2.5 million residents live within OCWD's boundaries and rely upon the basin for their primary water supply. OCWD manages water resource monitoring programs, land use elements related to basin management, groundwater elevation, groundwater quality, and coastal area monitoring through a number of monitoring programs. OCWD monitors the basin by collecting groundwater elevation and quality data from approximately 400 District-owned wells and manages an

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electronic database that stores water elevation, water quality, production, recharge, and other data on over 2,000 wells and facilities within and outside OCWD boundaries (OCWD, 2023). For detailed monitoring programs and management information, refer to the 2017 Basin 8-1 Alternative (Appendix D).

Groundwater levels are managed within a safe basin operating range to protect the long-term sustainability of the OC Basin and to protect against land subsidence. OCWD, a member of the agency of MWDOC, purchases untreated water from MET for basin recharge, as needed. In addition, OCWD regulates groundwater levels in the OC Basin by regulating the annual amount of pumping and setting the BPP for the water year. As defined in the District Act, the BPP is the ratio of water produced from groundwater supplies within the OCWD service area to all water produced within the area from both supplemental sources and groundwater within the OCWD (OCWD, 2020a). More information regarding the BPP is discussed in Section 6.3.1.3.

6.3.1.1 Basin Characteristics
The OC Basin underlies the northern half of Orange County beneath broad lowlands. The OC Basin, managed by OCWD, covers an area of approximately 350 sq mi, bordered by the Coyote and Chino Hills to the north, the Santa Ana Mountains to the northeast, and the Pacific Ocean to the southwest. The OC Basin boundary extends to the Orange County-Los Angeles Line to the northwest, where groundwater flows across the county line into the Central Groundwater Basin of Los Angeles County. A map of the OC Basin is shown on Figure 6.4. The total thickness of sedimentary rocks in the OC Basin is over 20,000 feet, with only the upper 2,000 to 4,000 feet containing fresh water. The OC Basin's estimated full storage volume is approximately 66 MAF.

There are three major aquifer systems that have been subdivided by OCWD: the Shallow Aquifer System, the Principal Aquifer System, and the Deep Aquifer System. These three aquifer systems are hydraulically connected as groundwater can flow between them through intervening aquitards or discontinuities in the aquitards. The Shallow Aquifer system occurs from the surface to approximately 250 feet below ground surface. Most of the groundwater from this aquifer system is pumped by small water systems for industrial and agricultural use. The Principal Aquifer system occurs at depths between 200 and 1,300 feet below ground surface. Over 90 percent of groundwater production is from wells that are screened within the Principal Aquifer system. Only a minor amount of groundwater is pumped from the Deep Aquifer system, which underlies the Principal Aquifer system and is up to 2,000 feet deep in the center of the OC Basin.

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Figure 6.4 Map of the OC Basin (OCWD, 2022 (Basin 8-1 Alternative 2022 Update))

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6.3.1.2 Sustainable Groundwater Management Act
In 2014, the State of California adopted the Sustainable Groundwater Management Act (SGMA) to promote sustainable groundwater management and limit "undesirable results", including significant groundwater-level declines, land subsidence, and water quality degradation. SGMA requires all high- and medium-priority basins, as designated by DWR, to be sustainably managed. DWR designated the Coastal Plain of the OC Basin (Basin 8-1) as a medium-priority basin, primarily due to heavy reliance on groundwater as a water supply source.

Compliance with SGMA can be achieved in one of the following two ways (OCWD, 2023):

1. Formation of a Groundwater Sustainability Agency (GSA)and adoption of a Groundwater Sustainability Plan (GSP).

2. Preparation and submittal of an Alternative to a GSP by eligible agencies, including special act districts such as OCWD.

Agencies within Basin 8-1, including OCWD, the City of La Habra, and the Irvine Ranch Water District (IRWD), collaborated to submit the original Alternative to a GSP in 2017, titled the "Basin 8-1 Alternative" to demonstrate compliance with SGMA. Under SGMA, alternatives and GSPs must be updated every 5 years. OCWD prepared its first periodic update in 2022.

For the remainder of this report, when the term "OC Basin" is used, it refers to the portion of Basin 8-1 that is within OCWD's service area (see Figure 6.5).

Figure 6.5 Basin 8-1 Management Areas (OCWD, 2023)

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6.3.1.3 Basin Production Percentage
Background
The OC Basin is not adjudicated; therefore, groundwater production is managed through a framework that uses financial incentives to encourage sustainable pumping. The framework is based on the BPP, which represents the percentage of each Producer's total water supply that comes from groundwater pumped from the OC Basin. Groundwater production at or below the BPP is assessed by the Replenishment Assessment (RA). While there is no legal limit as to how much an agency pumps from the OC Basin, there is a financial impact to pump above the BPP. The BPP is set uniformly for all Producers by OCWD on an annual basis. Agencies that pump above the BPP are charged the RA plus the Basin Equity Assessment (BEA). The BEA is calculated so that the cost of groundwater production above the BPP is equivalent to the cost of importing potable water supplies. This approach ensures there is no financial advantage for production above the BPP. The BEA can be increased to discourage production above the BPP if necessary.

The BPP is set annually by OCWD based on groundwater conditions, availability of imported water supplies, and OC Basin management objectives. The supplies available for recharge must be estimated for a given year. The estimated supplies of recharge water include: (1) stormflow from the Santa Ana River and Santiago Creek; (2) natural incidental recharge; (3) Santa Ana River baseflow; (4) GWRS supplies; and (5) other supplies such as imported water and recycled water purchased for the Alamitos Barrier.

The BPP is a major factor in determining the cost of groundwater production from the OC Basin. For the 2026–27 water year, OCWD maintained a BPP of 85 percent. Under normal hydrologic conditions, groundwater production could reach approximately 315,000 AFY. However, actual production in FY 2026-27 is expected to be approximately 299,000 AFY due to PFAS-related impacts that continue to limit groundwater availability among several producers.

BPP Adjustments for Basin Management
OCWD has established management guidelines that are used to establish future BPPs, as seen in Table 6.9. Raising or lowering the BPP allows OCWD to manage the amount of pumping from the basin.

OCWD has a policy to manage the groundwater basin within a sustainable range to avoid adverse impacts to the basin. OCWD seeks to maintain some available storage space in the basin to maximize surface water recharge when such supplies are available, especially in relatively wet years. By keeping the basin relatively full during wet years, and for as long as possible in years with near-normal recharge, the maximum amount of groundwater could be maintained in storage to support pumping in future drought conditions. During dry hydrologic years, when less water is available for recharge, the BPP could be lowered to maintain groundwater storage levels. A component of OCWD's BPP policy is to manage the groundwater basin so that the BPP will not fluctuate more than 5 percent from year to year.

The OCWD's GWRS came online in 2008 with a capacity of approximately 70 million gallons per day (mgd) and was expanded to 100 mgd in 2015. In 2023, it was expanded again to a final capacity of 130 mgd. The GWRS provides a resilient local water supply that recharges the OC Basin with advanced treated wastewater. The additional yield supported OCWD's move to raise the BPP from the long-standing approximately 77 percent level prior to 2023 to 85 percent beginning in February 2023. Monthly water resources reports show agencies achieving 86 to 88 percent pumping shares after the final expansion in

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late-2024 to early-2025, which reflects increased reliance on local groundwater supplies enabled by GWRS, along with the reduced water demands of approximately 400,000 AFY.

Modeling and forecasts generate estimates based on historical averages. Consequently, forecasts use average hydrologic conditions, which smooth the dynamic and unpredictable local hydrology. Variations in local hydrology are the most significant impact to supplies of water available to recharge the groundwater basin. The current BPP of 85 percent is based on modeling of average annual rainfall weather patterns and estimated groundwater recharge volumes. If OCWD were to experience a relatively dry period, the BPP could be reduced to maintain water storage levels, along with other management actions shown in Table 6.9.

Table 6.9 Management Actions Based on Changes in Groundwater Storage Available Storage Space(1) Basin Management Action to Consider Less than 100,000 AF Raise BPP
100,000 to 300,000 AF Maintain and/or raise BPP towards 85% goal 300,000 to 350,000 AF Seek additional supplies to refill basin and/or lower the BPP Greater than 350,000 AF Seek additional supplies to refill basin and lower the BPP Notes:
(1) Amount below full basin condition.

Basin Equity Assessment Exemptions
In some cases, OCWD encourages treating and pumping groundwater that does not meet drinking water standards to protect water quality. This is achieved by using a financial incentive called the BEA Exemption. A BEA Exemption is used to promote beneficial uses of poor-quality groundwater and reduce or prevent the spread of poor-quality groundwater into non-degraded aquifer zones. OCWD uses a partial or total exemption of the BEA to compensate a qualified participating agency or Producer for the costs of treating poor quality groundwater, which typically include capital, interest, and operations and maintenance costs for treatment facilities (City of La Habra et al., 2017). Similarly, for proactive water quality management, OCWD occasionally exempts a portion of the BEA for its Coastal Pumping Transfer Program (CPTP). The CPTP encourages inland groundwater producers to increase pumping and coastal producers to decrease pumping to reduce the groundwater basin drawdown at the coast and protect against seawater intrusion. Inland pumpers can pump above the BPP without having to pay the full BEA for the amount pumped above the BPP (OCWD, 2015). Coastal pumpers receive BEA revenue from OCWD to assist in offsetting their additional water supply cost from taking less groundwater.

OCWD Resilience Plan
To address evolving conditions within OCWD's service area, it is important to anticipate potential challenges and proactively plan for strategies that sustain and enhance water supply reliability, water quality, and overall system resilience. The OCWD Resilience Plan is an adaptive management plan that evaluates future water demands and available supplies, while also identifying potential projects and response strategies to address risks to key District assets, including the groundwater basin, Santa Ana River, groundwater replenishment facilities, and natural resources.

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The plan builds on OCWD's historical planning efforts and provides a flexible, project-based framework to maintain sustainable basin conditions and strengthen the long-term resilience of the District's water resources over a 5- to 25-year planning horizon.

The Resilience Plan also supports evaluation of future water supply projects, recharge strategies, and operational improvements to guide management of the OC Basin under changing hydrologic, regulatory, and demand conditions.

The Basin 8-1 Alternative submitted to DWR in 2017 showed that Basin 8-1 had been sustainably managed for the prior 10 years, which was a SGMA requirement. Based on avoiding undesirable results as defined in SGMA, the OC Basin has been sustainably managed since the construction of the Talbert Seawater Intrusion Barrier in the mid-1970s. Required annual reports and periodic updates submitted to DWR show that Basin 8-1 continues to be sustainably managed.

Current water demand projections show a relatively slow increase over the 25-year planning horizon, which is generally of similar magnitude as the additional production from the GWRS since its final expansion in early 2023 to 130 mgd. This locally controlled, drought-proof supply of water reduces the region's dependence on imported water.

Historically, the Santa Ana River has served as the primary source of water to recharge the OC Basin. To determine the availability of future Santa Ana River flows, OCWD utilized surface water flow modeling of the upper watershed. Modeling was developed to predict the impacts that future stormwater capture and wastewater recycling projects in the upper watershed would have on future Santa Ana River flow rates at Prado Dam. Santa Ana River base flows are expected to decrease as more water recycling projects are built in the upper watershed. OCWD continues to work closely with the US Army Corps of Engineers (USACE) to temporarily impound and slowly release up to approximately 20,000 AF of stormwater in the Prado Dam Conservation Pool. The amount of water that can be temporarily impounded in the conservation pool has grown over time, and in 2025 it was increased to over 25,000 AF. To some extent, the losses in baseflow are partially offset through the capture of additional stormwater held in the Prado Dam Conservation Pool. When available, OCWD will continue to augment groundwater recharge through the purchase of imported water through MET. OCWD will diligently monitor and evaluate future water supply projects to sustainably manage and protect the OC Basin for future generations.

OCWD Engineer's Report
The OCWD Engineer's Report documents groundwater conditions and evaluates water supply and basin utilization within OCWD's service area. The most recent report is the 2024–25 Engineer's Report filed in March 2026. As reported, the BPP for the 2024–25 water year was established at 85 percent by the OCWD Board of Directors. The overall BPP achieved within OCWD for non‑irrigation use was 83.8 percent, with the reduced achievement attributed primarily to PFAS‑related well shutdowns. Groundwater stored in the basin decreased by 50,000 AF for the 2024–25 water year, and the annual overdraft was 165,300 AF, which reflects the amount by which natural replenishment was exceeded. The decrease in storage was reflected by a relatively dry year, and the total groundwater recharge was 252,214 AF, which included contributions from supplemental water recharged by the GWRS.

For the 2026–27 water year, OCWD is proposing to maintain a BPP of 85 percent. Under normal hydrologic conditions, groundwater production could reach approximately 315,000 AF; however, OCWD

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anticipates groundwater production during 2026–27 will be approximately 299,000 AF due to PFAS-related impacts that continue to limit groundwater availability among several producers.

It is estimated that approximately 13,500 AF of additional production above the BPP will be undertaken by the City of Tustin, City of Huntington Beach, Mesa Water District, and Irvine Ranch Water District to support groundwater quality improvement projects. As in prior years, groundwater produced above the BPP for these water‑quality projects will be partially or fully exempt from the BEA due to the basin‑wide benefit of pumping and treating poor‑quality groundwater.

During the 2024–25 water year and the current 2025-26 water year, MET untreated full‑service water supplies were available for groundwater replenishment; however, OCWD did not purchase replenishment water due to favorable basin storage conditions. OCWD likewise does not plan to purchase untreated full‑service water for replenishment in 2026–27.

6.3.1.4 Recharge Management
Recharging water into the OC Basin through natural and artificial means is essential to support pumping from the OC Basin. Active recharge of groundwater began in 1936, in response to increasing drawdown of the OC Basin and, consequently, the threat of seawater intrusion. The OC Basin's primary source of recharge is supplied from the Santa Ana River, which is diverted into recharge basins and its main Orange County tributary, Santiago Creek. Other sources of recharge water include natural infiltration, recycled water, and imported water. Natural recharge consists of subsurface inflow from local hills and mountains, infiltration of precipitation and irrigation water, recharge in small flood control channels, and groundwater underflow to and from Los Angeles County and the ocean.

Recycled water for OC Basin recharge is from two sources. The main source is the GWRS, which completed its final expansion in 2023 and now produces up to 130 mgd of advanced‑purified water for recharge at the Talbert Seawater Barrier and in the Kraemer, Miller, Miraloma, and La Palma basins. The second source is recycled water purified at the Water Replenishment District of Southern California's (WRD) Leo J. Vander Lans Advanced Water Treatment Facility (LVL), which provides up to 8 mgd for injection at the Alamitos Seawater Barrier (owned and operated by the Los Angeles County Department of Public Works). In recent years, WRD's upgrades and operations have increased the use of recycled water at the Alamitos Barrier and reduced reliance on imported supplies. Injection of recycled water into these barriers is an ongoing effort by OCWD (in coordination with WRD and Los Angeles County) to control seawater intrusion into the OC Basin; operation of the injection wells forms a hydraulic barrier to seawater intrusion.

OCWD also purchases imported water for recharge through MWDOC. Untreated imported water can be used to recharge the OC Basin through the surface recharge system at multiple locations, such as Anaheim Lake, the Santa Ana River, Irvine Lake, and San Antonio Creek, while treated imported water may be used for in‑lieu recharge when appropriate. For the current planning context and detailed recharge management strategies, refer to OCWD's most recent planning documents, including the 2024 OCWD Resilience Plan, in addition to prior foundational documents (Appendix E).

6.3.1.5 MET Imported Water for Groundwater Replenishment In the past, OCWD, MWDOC, and MET have coordinated water management to increase storage in the OC Basin when imported supplies are available for this purpose. MET's groundwater replenishment program was discontinued on January 1, 2013, and currently MET via MWDOC sells replenishment water

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to OCWD at the full-service untreated MET rate. Figure 6.6 shows MWDOC's imported water sales to OCWD since FY 1990-91, which averages approximately 27,888 AF per year. In three of the past five water years, OCWD did not need to purchase more imported water to replenish groundwater.

Figure 6.6 MWDOC Imported Water Sales for Groundwater Replenishment

6.3.2 Planned Future Groundwater Sources
Although not new sources, the City plans to rehabilitate the Walker Street and City Yard Wells to ensure reliable local groundwater and continued drinking water safety.

On a regional scale, OCWD regularly evaluates potential projects and conducts studies to review the feasibility of new projects or sources. Groundwater basin-related projects that are planned or in progress are described below:

Forecast Informed Reservoir Operations (FIRO) at Prado Dam - Stormwater represents a significant source of water used by OCWD to recharge the OC Basin. Much of this recharge is made possible by the capture of Santa Ana River stormflows behind Prado Dam in the Conservation Pool. FIRO represents the next generation of operating water reservoirs using the best available technology. Advances in weather and stormwater runoff forecasting hold promise to allow USACE to safely impound more stormwater while maintaining equivalent flood risk management capability behind Prado Dam. Analyses indicate that FIRO would increase average annual recharge by approximately 4,000–6,000 AFY, and up to 23,000 AF in very wet years, consistent with earlier preliminary analyses. Federal and local partners have indicated FIRO at Prado Dam is moving from technical assessment toward implementation via Water Control Manual (WCM) updates.

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6.4 Surface Water

6.4.1 Existing Surface Water Sources
There are, currently, no direct surface water uses in the City's Service area.

6.4.2 Planned Future Surface Water Sources
As of 2025, there are no planned surface water uses in the City's service area.

6.5 Stormwater

6.5.1 Existing Stormwater Sources
There are, currently, no direct stormwater uses in the City's Service area.

6.5.2 Planned Future Stormwater Sources
As of 2025, there are no planned stormwater uses in the City's service area.

6.6 Wastewater and Recycled Water
The City is directly involved in wastewater services through its ownership and operation of the wastewater collection system in its service area. However, the City does not own or operate wastewater treatment facilities. The City's sewer system includes approximately 30 miles of sewer lines and 635 manholes. The wastewater system serves about 4,000 connections (La Palma's Sewer Master Plan, 2013). For additional details on La Palma's wastewater services, refer to the 2013 La Palma Sewer Master Plan.

Recycled water is wastewater that is treated through primary, secondary, and tertiary processes and is acceptable for most non-potable water purposes, such as irrigation, and commercial and industrial process water per Title 22 requirements. Recycled water opportunities have continued to grow in Southern California, as public acceptance and the need to expand local water resources continue to be a priority. Recycled water also provides a degree of flexibility and added reliability during drought conditions when imported water supplies are restricted. The City does not use recycled water. The City is indirectly involved in recycled water production through its supply of wastewater for IPR. The following sections expand on the existing agency collaboration involved in these efforts, as well as the City's projected recycled water use over the next 25 years.

6.6.1 Agency Coordination
The City does not own or operate wastewater treatment facilities and sends all collected wastewater to OC San for treatment and disposal. OC San provides treated water to OCWD, the manager of the OC Basin. OCWD is the manager of the OC Basin and strives to maintain and increase the reliability of the OC Basin through replenishment with imported water, stormwater, and advanced treated wastewater. A full description of the OC Basin is available in Section 6.3.1. OCWD and OC San have jointly constructed and expanded two water recycling projects to meet this goal, which include: (1) OCWD Green Acres Project (GAP); and (2) OCWD GWRS.

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6.6.1.1 Orange County Sanitation District
OC San collects wastewater from residential, commercial, and industrial customers in 20 cities, four special districts, and portions of unincorporated Orange County, totaling 479 square miles, that serve more than

2.6 million residents in northwest and central Orange County (OC San, 2017). These flows include dry weather urban runoff collected from 15 diversion points and discharged into the sewer system for treatment and Santa Ana River Interceptor flows from the upper Santa Ana watershed (OC San, 2017).

OC San operates and maintains two treatment plants: Reclamation Plant No. 1, located in Fountain Valley with a capacity of 320 mgd, and Reclamation Plant No. 2 located in Huntington Beach with a capacity of 312 mgd. OC San also operates 572 miles of collection system pipelines along with 15 offsite pump stations. Approximately 150 mgd of secondary effluent undergoes advanced treatment at the GWRS facility operated by the OCWD and 7 mgd undergoes tertiary treatment at OCWD's GAP facility. Treated wastewater is discharged to the Pacific Ocean via an ocean outfall in compliance with state and federal requirements as set forth in OC San's National Pollutant Discharge Elimination System (NPDES) permit.

OC San's ocean outfall is 120-inch diameter and extends four miles off the coast of Huntington Beach. A 78-inch diameter emergency outfall also exists that extends 1.3 miles off the coast (OC San, 2017).

OC San Reclamation Plant No. 1 - Reclamation Plant No. 1 treats raw wastewater and has a maximum treatment capacity of 320 mgd. The plant provides primary and secondary treatment and supplies secondary effluent to OCWD for further tertiary treatment at their GAP facility and advanced treatment at their GWRS. Reclamation Plant No. 1 is the only plant that provides water to OCWD for additional treatment and recycling. An interplant pipeline allows flows to be conveyed to Treatment Plant No. 2.

OC San Treatment Plant No. 2 - Treatment Plant No. 2 provides primary and secondary treatment to raw wastewater and has a maximum treatment capacity of 312 mgd. All secondary effluent from their plant is discharged to the ocean through the ocean outfall.

6.6.1.2 Orange County Water District
OCWD is the manager of the OC Basin and provides water to 19 municipal water agencies and special districts. A full description of the OC Basin is available in Section 6.3.1. OCWD and OC San have jointly constructed and expanded two water recycling projects that include: (1) OCWD GAP; and (2) OCWD GWRS.

OCWD GAP
OCWD owns and operates the GAP, a water recycling system that treats up to 7.5 mgd and provides 8,400 AFY of recycled water for irrigation and industrial uses. GAP provides an alternate source of water that is mainly delivered to parks, golf courses, greenbelts, cemeteries, and nurseries in the cities of Costa Mesa, Fountain Valley, Newport Beach, and Santa Ana. Approximately 100 customer sites use GAP water, current recycled water users include Mile Square Park and Golf Courses in Fountain Valley, Costa Mesa Country Club, Chroma Systems carpet dyeing, Kaiser Permanente, and Caltrans.

OCWD GWRS
OCWD's GWRS allows southern California to decrease its dependency on imported water and creates a local and reliable source of water. OCWD's GWRS purifies secondary treated wastewater from OC San to levels that meet and exceed all state and federal drinking water standards. The GWRS Phase 1 plant has

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been operational since January 2008 and uses a three-step advanced treatment process consisting of MF, RO (RO), and ultraviolet (UV) light with hydrogen peroxide. A portion of the treated water is injected into the seawater barrier to prevent seawater intrusion into the groundwater basin. The other portion of the water is pumped to ponds where the water percolates into deep aquifers and becomes part of Orange County's water supply. The treatment process is described on OCWD's website. (OCWD, GWRS, 2020).

The GWRS first began operating in 2008 producing 70 mgd and in 2015, it underwent a 30 mgd expansion. Approximately 39,200 AFY of the highly purified water is pumped into the injection wells and 72,900 AFY is pumped to the percolation ponds in the City of Anaheim where the water is naturally filtered through sand and gravel to deep aquifers of the groundwater basin. The OC Basin provides approximately 77 percent of the potable water supply for north and central Orange County. The design and construction of the first phase (78,500 AFY) of the GWRS project was jointly funded by OCWD and OC San; Phase 2 expansion (33,600 AFY) was funded solely by OCWD.

The Final Expansion of the GWRS is the third and final phase of the project and was completed in 2023.

The plant now produces 130 mgd and requires additional treated wastewater from OC San. This additional water comes from OC San's Treatment Plant 2, which is in the City of Huntington Beach approximately 3.5 miles south of the GWRS. The Final Expansion project included expanding the existing GWRS treatment facilities, constructing new conveyance facilities at OC San Plant 2, and rehabilitating an existing pipeline between OCSD Plant 2 and the GWRS. Following completion, the GWRS plant now recycles 100 percent of OC San's reclaimable sources and produces enough water to meet the needs of over one million people.

6.6.2 Wastewater
The City operates and maintains the local sewer collection pipes that feed into the OCSD's trunk sewer system. The City's sewer system includes approximately 30 miles of sewer lines and 635 manholes. The wastewater collected in the City's system is conveyed to OCSD's extensive system of gravity flow sewers, pump stations, and pressurized sewers. Ultimately, the wastewater is treated at OCSD treatment plants in Fountain Valley (Plant No. 1) and Huntington Beach (Plant No. 2). Table 6.10 summarizes the wastewater collected by the City and transported to OCSD's system in 2025.

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Table 6.10 Submittal Table 6-2 Retail: Wastewater Collected within the City's Service Area in 2025 Submittal Table 6-2 Retail: Wastewater Collected Within Service Area in 2025 Water Code Section 10633(a)
Wastewater Collection Recipient of Collected Wastewater Name of Wastewater
Collection Agency
Wastewater Volume
Metered or Estimated?
Volume of Wastewater
Collected from UWMP
Service Area 2025
Name of Wastewater
Treatment Plant (WWTP)
and Place ID Number
Is WWTP Located
Within UWMP
Area?
(AF)
City of La Palma Estimated 1,587 OCSD Plant 1,
Place ID 758392
No
OCSD Plant 2,
Place ID 259158
No
Total Wastewater Received from UWMP
Service Area in 2025:
1,587
NOTES: There is an estimated a return rate of 95 percent based on per capita usage from sewer master plan (City of La Palma, 2013).

6.6.3 Current Recycled Water Uses
There are currently no direct recycled water uses within the City's service area. For indirect use, the City also benefits from OCWD's GWRS system that provides IPR through replenishment of OC Basin with water that meets state and federal drinking water standards.

6.6.4 Projected Recycled Water Uses
As of April 2019, the State of California amended its recycled water policy to expand its numeric goal of recycled water use to 2.5 million AFY by 2030 and added annual required reporting requirements for wastewater and recycled water. The City does not have any direct non-potable uses within their service area and does not currently have the potential for non-potable reuse because of nonexistent or planned recycled water infrastructure. The City will continue to supply wastewater to support the region's IPR via GWRS.

6.6.5 Potential Recycled Water Uses
While the City recognizes the potential for beneficial reuse in their service area, there is no source of recycled water supply in proximity to the City. The City's wastewater is conveyed to OCSD's regional treatment facilities where the wastewater is treated, recycled, or discharged to the ocean. Recycled water analyses performed over the years have shown that local treatment and reuse facilities are not feasible.

The City supports the continued development of recycled water and potential uses throughout the region with OCWD's GWRS.

6.6.6 Optimization Plan
Studies of water recycling opportunities within Southern California provide a context for promoting the development of water recycling plans. It is recognized that broad public acceptance of recycled water requires continued education and public involvement. Currently, most of the recycled water available

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being directed toward replenishment of the groundwater basin and improvements in groundwater quality. As a user of groundwater, the City supports the efforts of OCWD and OCSD to use recycled water as a primary resource for groundwater recharge in Orange County.

6.6.6.1 Public Education
The City participates in the MWDOC public education and school education programs, which include information on water recycling. MWDOC's water use efficiency public information programs are a partnership with agencies throughout the county. Through a variety of public information programs, MWDOC reaches the public, including those in the City, with information regarding present and future water supplies, the demands for a suitable quantity and quality of water, including recycled water, and the importance of implementing water efficiency techniques and behaviors. Through MWDOC, water education programs have reached thousands of students in the City with grade-specific programs that include information on recycled water.

6.6.6.2 Financial Incentives
The implementation of recycled water projects involves a substantial upfront capital investment for planning studies, Environmental Impact Reports (EIRs), engineering design, and construction before recycled water is available to the market. The establishment of new supplemental funding sources through federal, state, and regional programs now provides significant financial incentives for water agencies to develop and make use of recycled water locally. Potential sources of funding include federal, state, and local funding opportunities. These funding sources include USBR, California Proposition 13 Water Bond, Proposition 84 and MET Local Resources Program (LRP). These funding opportunities may be sought by the City or possibly more appropriately by regional agencies. The City will continue to support seeking funding for regional water recycling projects and programs.

6.6.6.3 Optimization Plan
The City does not use recycled water, therefore, there is no need for a recycled water optimization plan. In other areas of Orange County, recycled water is used for irrigating golf courses, parks, schools, businesses, and communal landscaping, as well as for groundwater recharge. Analyses have indicated that present worth costs to incorporate recycled water within the City are not cost effective as compared to purchasing imported water from MWDOC or using groundwater. The City will continue to conduct feasibility studies for recycled water and seek out creative solutions such as funding, regulatory requirements, institutional arrangement, and public acceptance for recycled water use with MWDOC, OCWD, MET, and other cooperative agencies.

6.7 Desalination Opportunities

6.7.1 Ocean Water Desalination
There are currently no ocean desalination opportunities within the City's service area

6.7.2 Groundwater Desalination
There are currently no brackish groundwater opportunities within the City's service area.

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6.8 Water Exchanges and Transfers

6.8.1 Existing Exchanges and Transfers
Interconnections with other agencies result in the ability to share water supplies during short term emergency situations or planned shutdowns of major imported water systems. Transfers of water can help with short-term outages but can also be involved with longer term water exchanges to deal with droughts or long-term emergency situations.

The City maintains two emergency interconnections with the City of Cerritos that are both metered. One is located on Valley View and 183rd Street, and the other at Moody Street and Houston Avenue. The interconnection on Valley View is a 16-inch two-way connection that is hydraulically controlled to allow water to pass either way based on the pressure differential. The connection on Moody Street is a 'hard' connection between the water systems isolated by valves on both sides (Infrastructure Engineers, 2020).

The City has developed an interconnection with the City of Buena Park to further increase water supply resiliency. The interconnection is located on the east side of the City on Thelma Avenue where the two systems are adjacent. This connection includes hydraulically operated valves and a meter, serving both cities if either system experiences a loss of pressure (Infrastructure Engineers, 2020).

6.8.2 Planned and Potential Exchanges and Transfers
MWDOC supports its retail agencies, such as the City, in developing both local and regional transfer and exchange opportunities that promote reliability within their systems. Examples of these future projects include:

Santa Ana River Conservation and Conjunctive Use Project - SARCCUP is a joint project established by five regional water agencies within the Santa Ana River Watershed (Eastern Municipal Water District, Inland Empire Utilities Agency, Western Municipal Water District, Orange County Water District, and San Bernardino Valley Municipal Water District). In September 2021, the participating agencies, in coordination with MET, executed a regional agreement framework establishing SARCCUP as a watershed-scale groundwater banking program to improve drought reliability across Orange, Riverside, and San Bernardino counties.

In 2016, SARCCUP received $55 million in Proposition 84 funding from DWR; however, implementation has since advanced with the 2021 agreements and subsequent program updates. The overall SARCCUP program consists of three main elements: (1) Watershed-Scale Cooperative Water Banking Program; (2) Water Use Efficiency—landscape design/irrigation improvements and water budget assistance; and (3) Habitat creation and Arundo donax removal within the Santa Ana River.

The Watershed-Scale Cooperative Water Banking Program is the largest component of SARCCUP. Under MET's arrangement with San Bernardino Valley Municipal Water District (Valley), when Valley declares surplus SWP water and offers it to MET, MET offers at least 50 percent of an equivalent amount to SARCCUP member agencies for storage and later use in the Santa Ana River watershed, consistent with MET policy. This structure formalizes the purchase and storage pathway that had been under development and aligns with MET's extraordinary supply policy during allocations.

Program capacity planning identifies up to approximately 137,000 AF of storage across six basins, including up to 36,000 AF in the OC Basin for use in dry years. Stored SARCCUP supplies may be

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designated "extraordinary supplies" during a MET allocation if managed consistent with MET's Water Supply Allocation Plan, thereby enhancing participating agencies' drought reliability.

Within Orange County, extraordinary supply assignment agreements among MET, MWDOC/OCWD, and certain retail agencies (e.g., Anaheim, Fullerton, Santa Ana) document how SARCCUP extraordinary supply is assigned and delivered locally. Program implementation and participation details continue to be refined among OCWD, retail agencies, and MWDOC.

6.9 Future Water Projects
The City continually reviews practices that will provide its customers with adequate and reliable supplies.

Trained staff continue to ensure the water quality is safe and the water supply will meet present and future needs in an environmentally and economically responsible manner. Although the City has various projects planned to maintain or improve the water system (Section 6.9.1), there are currently no City-specific planned projects that have both a concrete timeline and a quantifiable increase in normal water supply.

6.10 Energy Intensity
Although the City does not have operational control over the downstream portions of the water system, the energy efficiency of these systems is important to the City focus on sound planning and appropriate investments in water supply, water use efficiency, regional delivery infrastructure, and emergency preparedness. To this end, awareness of the energy intensity of retail agencies helps with planning for future system needs. By setting a baseline, agencies can better understand and manage their operational expenditures. Several factors will affect the energy intensity of water delivery over time, such as static groundwater levels, total water demand, and proportion of local to imported supply. When tracking energy intensity over time, agencies should keep factors such as these in mind and focus on the efficiency of each facility they operate.

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CHAPTER 7 WATER SERVICE RELIABILITY AND DROUGHT

RISK ASSESSMENT
This chapter of the Urban Water Management Plan (UWMP) describes the City of La Palma's water service reliability assessment for three long-term hydrological conditions: a normal year, a single dry year, and a drought period lasting five consecutive years. The Drought Risk Assessment assesses water supply reliability during a severe drought lasting the next five consecutive years, from 2026 to 2030. Factors affecting reliability, such as water quality, regulations, and climate change, are also summarized in this assessment of reliability.

7.1 Water Service Reliability Overview
As part of the UWMP, every urban water supplier is required to assess the reliability of their water service to its customers under a normal year, a single dry year, and multiple dry years. The City of La Palma's water sources are from local groundwater and imported water purchased from the Municipal Water District of Orange County (MWDOC). MWDOC is one of 26 member agencies of the Metropolitan Water District of Southern California (MET), which imports water from the Colorado River through its own Colorado River Aqueduct (CRA) and from Northern California through the California Aqueduct managed by the State Water Project (SWP).

MET has also invested in numerous programs and projects to augment its direct deliveries of imported water such as water transfers, groundwater banking, and use of its reservoir storage as summarized in Chapter 6.

Local groundwater in the Orange County Groundwater Basin (OC Basin) is managed by the Orange County Water District (OCWD). As summarized in Chapter 6, OCWD has developed programs and projects to improve groundwater recharge and augment groundwater through recycled water, conjunctive use, and water transfers. OCWD assesses groundwater conditions and sets its basin production percentage (BPP), which determines how much water will be pumped from the basin year, and the Basin Equity Assessment (BEA), which is a surcharge for exceeding the BPP. Currently, the BPP is set at 85 percent.

Likewise, MET has also invested in numerous programs and projects to augment its direct deliveries of imported water, such as water transfers, groundwater banking, and use of its reservoir storage, as summarized in Chapter 6. MET's draft 2025 UWMP demonstrates that MET will be able to meet its projected water demands for the next 25 years under normal, dry, and multiple dry year conditions (MET, 2025).

In 2025, all water agencies in Orange County, in collaboration with their wholesalers, MWDOC and OCWD, developed a water demand forecast model for their service areas that estimated water demand at the individual retail water agency level. The demand model statistically correlates municipal and industrial (M&I) water use with demographic, socioeconomic, conservation, and weather variables as reported in the 2025 Orange County Water Demand Projection Model TM (MWDOC, 2025). Because the model isolates weather, future water demand can be estimated under single and multiple-year droughts and under future climate change scenarios. The model used a 33-year dataset (1991-2024) to estimate demand under average (normal), single-dry year, and five consecutive dry years hydrologic conditions. Correlation

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coefficients between demand, temperature, and precipitation were applied to the hottest and driest historical sequences to calculate high-demand scenarios, which were expressed as scaling factors relative to the 33-year average demand.

Table 7.1 Optional Submittal Table 7-1 Retail: Basis of Water Year Data (Reliability Assessment) OPTIONAL Submittal Table 7-1 Retail: Basis of Water Year Data (Reliability Assessment) Year Type
Base Year If not using a calendar
year, type in the last
year of the fiscal,
water year, or range of
years, for example,
water year 2024-2025,
use 2025
Available Supplies if
Year Type Repeats
Check the box if quantification of available
supplies is not compatible with this table and is
provided elsewhere in the UWMP.

Location: [insert location from UWMP]
Quantification of available supplies is provided in this table as either volume only, percent only, or both.

Volume Available
% of Average Supply
Average Year 1991-2024 100%
Single-Dry Year 2014 107%
Consecutive Dry Years 1st Year 1991-2024 107%
Consecutive Dry Years 2nd Year 1991-2024 112%
Consecutive Dry Years 3rd Year 1991-2024 113%
Consecutive Dry Years 4th Year 1991-2024 115%
Consecutive Dry Years 5th Year 1991-2024 117%

7.2 Factors Affecting Water Supply Reliability
To prepare realistic water supply reliability assessments, various factors affecting reliability were considered. These include climate change and environmental requirements, regulatory changes, water quality impacts, and locally applicable criteria. In May 2025, DWR published a technical addendum to the 2023 State Water Project Delivery Capability Report (DCR) describing the impact of subsidence to future SWP deliveries. The study showed that SWP deliveries could be reduced by future subsidence. DWR recommends using the 2025 DCR to support long-term planning efforts because DWR has planned near-term fixes and is committed to restoring the conveyance capacity of the California Aqueduct. MET will continue to stay informed and incorporate any suitable subsidence modeling in the future.

7.2.1 Climate Change and the Environment
Changing climate patterns are expected to shift precipitation patterns and affect water supply availability.

Unpredictable weather patterns will make water supply planning more challenging. Although climate change impacts are associated with exact timing, magnitude, and regional impacts of these temperature and precipitation changes, researchers have identified several areas of concern for California water planners (Climate Adaptation Master Plan for Water [CAMP4W], 2025). These areas include:
 A reduction in Sierra Nevada Mountain snowpack.
 Extreme heat threatens both infrastructure and the health and safety of human lives.

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 Prolonged drought periods.
 Water quality issues associated with an increase in wildfires.  Rising sea levels resulting in:
» Impacts to coastal groundwater basins due to seawater intrusion. » Increased risk of damage from storms, high-tide events, and the erosion of levees. » Potential pumping cutbacks to the SWP and Central Valley Project (CVP).

Other important issues of concern due to global climate change include:
 Effects on local supplies such as groundwater.
 Changes in urban and agricultural demand levels and patterns.  Alterations to power generation and pumping regime.
 Increases in ocean algal blooms affected seawater desalination supplies.

Without additional surface storage, earlier and heavier runoff will flow to the ocean instead of being held as mountain snowpack, causing California to lose more water. California, therefore, needs to place a strong emphasis on expanding storage.

As described in Chapter 6, the Colorado River Basin supplies have been inconsistent since about the year 2000, with precipitation near normal while runoff has been less than average in two out of every three years. Climate models are predicting a continuation of this pattern, whereby hotter and drier weather conditions will result in continuing lower runoff, pushing the system toward a drying trend that is often characterized as long-term drought.

Dramatic swings in annual hydrologic conditions have affected water supplies available from the SWP over the last decade. The declining ecosystem in the Delta has also led to a reduction in water supply deliveries, and operational constraints will likely continue until a long-term solution to these problems is identified and implemented (MET, 2025).

Climate change is also projected to impact future water demands. The 2025 Orange County Water Demand Model TM developed a sensitivity for the water demand forecast based on using future climate variables from a subset of 15 downscaled global climate models (GCMs) from the World Climate Research Program (WCRP) Coupled Model Intercomparison Project (CMIP6). Future weather variables under two climate scenarios were substituted for baseline historical average weather, with the results indicating that projected water demands under one to five consecutive dry years could be 5 to 17 percent greater than baseline demands (MWDOC, 2025).

7.2.2 Regulatory and Legal
Ongoing regulatory restrictions, such as those imposed by the Biological Opinions (BiOps) on the effects of SWP and the Federal CVP operations on certain marine life, also contribute to the challenge of determining water delivery reliability. Endangered species protection and conveyance needs in the Delta have resulted in operational constraints that are particularly important because pumping restrictions impact many water resources programs – SWP supplies and additional voluntary transfers, Central Valley storage and transfers, and in-region groundwater and surface water storage. BiOps protect special-status species listed as threatened or endangered under the Endangered Species Act (ESA) and impose

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substantial constraints on Delta water supply operations through requirements for Delta inflow and outflow and export pumping restrictions.

In addition, the State Water Resources Control Board (SWRCB) has set water quality objectives that must be met by the SWP, including minimum Delta outflows, limits on SWP and CVP Delta exports, and maximum allowable salinity level. SWRCB has implemented the new Lower San Joaquin River flow objectives from the Phase 1 Delta Plan amendments through adjudicatory (water rights) and regulatory (water quality) processes. The Lower San Joaquin River flow objectives are estimated to reduce water available for municipal water use. New litigation, listings of additional species under the ESA, or regulatory requirements imposed by the SWRCB could further adversely affect SWP operations in the future by requiring additional export reductions, releases of additional water from storage, or other operational changes impacting water supply operations.

The Colorado River 2007 Interim Guidelines governing the Lower Basin water supply shortages and the operations of Lakes Mead and Powell are set to expire in 2026, and new operating guidelines will need to be developed for 2027 and beyond. At the time of this 2025 UWMP, negotiations over the successor post-2026 guidelines are ongoing and the outcome is highly uncertain. It is anticipated that California will likely be required to reduce its supplies from the Colorado River, on average, under the new guidelines, and that, as the junior priority, MET is at risk. A final EIS with a Selected Alternative is expected in the summer of 2026, with a record of decision to follow.

The difficulty and implications of environmental review, documentation, and permitting pose challenges for multi-year transfer agreements, recycled water projects, and seawater desalination plants. The timeline and roadmap for getting a permit for recycled water projects are challenging and inconsistently implemented in different regions of the state. Indirect Potable Reuse (IPR) projects face regulatory restraints such as treatment, blended water, retention time, and Basin Plan Objectives, which may limit how much recycled water can feasibly be recharged into the groundwater basins. New regulations and permitting uncertainty are also barriers to seawater desalination supplies, including updated Ocean Plan Regulations, Marine Life Protected Areas, and Once-Through Cooling Regulations (MET, 2025).

7.2.3 Water Quality
The following sub-section describes the water quality of the region's water supplies and the measures being taken to continue delivering high-quality drinking water that meets federal and state regulations.

7.2.3.1 Imported Water
MET is responsible for providing high-quality potable water throughout its service area. Over 250,000 water quality tests are performed per year on MET's water to test for regulated contaminants and additional contaminants of concern to monitor the safety of its waters (MET, 2025). MET's supplies originate primarily from the CRA and from the SWP. A blend of these two sources, proportional to each year's availability of the source, is then delivered throughout MET's service area.

Although the CRA and SWP have different water quality characteristics, MET has implemented effective treatment and management strategies to maintain high-quality water. The CRA water source contains higher total dissolved solids (TDS), and the SWP contains higher levels of naturally-occurring organic matter, lending to the formation of disinfection byproducts. To remediate the CRA's high level of salinity and the SWP's high level of organic matter, MET blends CRA and SWP supplies and has upgraded all its

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treatment facilities to include ozone treatment processes. In addition, MET has been engaged in efforts to protect its Colorado River supplies from threats of uranium, perchlorate, and chromium VI while also investigating the potential water quality impact of the following emerging contaminants:

N-nitrosodimethylamine (NDMA), pharmaceuticals and personal care products (PPCP), microplastics, per- and polyfluoroalkyl substances (PFAS), and 1,4-dioxane (MET, 2025).

PFAS is a group of widely used man-made "forever chemicals" that include both perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). MET has voluntarily monitored PFAS in its source and treated waters since 2017. Most samples have shown non-detect (ND) for all tested PFAS, including PFOA and PFOS. A limited number of other PFAS—such as PFHxA, PFBA, PFPeA, PFDoA, PFTA, and PFBS, have been detected only at trace levels below their method detection limits. PFOA and PFOS have not been detected in Metropolitan's imported or treated water supplies. Some member agencies, however, have detected these compounds in local groundwater wells, which may require treatment or source management to comply with emerging DDW regulations. As DDW and EPA establish enforceable maximum contaminant levels (MCLs) for PFOA and PFOS, some agencies may supplement their local supplies with increased purchases of Metropolitan water (MET, 2025).

EPA finalized the first national drinking water standards for six PFAS compounds in April 2024. These standards include enforceable Maximum Contaminant Levels (MCLs) for PFOA and PFOS set at 4 parts per trillion (ppt). In May 2025, the EPA announced that it would extend the compliance deadline for PFOA and PFOS from 2029 to 2031 to provide additional time for testing, planning, and installation of treatment technologies. While MET and its member agencies continue to monitor and test PFAS in imported and local sources, the delay in the federal compliance date allows additional time to evaluate treatment options, coordinate funding, and plan system upgrades necessary to meet forthcoming federal PFAS standards.

The presence of quagga mussels in water sources is a water quality concern. Quagga mussels are an invasive species that was first discovered in 2007 at Lake Mead, on the Colorado River. This species of mussels forms massive colonies in short periods of time, disrupting ecosystems and blocking water intakes. They can cause significant disruption and damage to water distribution systems. MET has had success in controlling the spread and impacts of the quagga mussels within the CRA; however, the future could require more extensive maintenance and reduced operational flexibility than current operations allow. It also resulted in MET eliminating deliveries of CRA water into Diamond Valley Lake (DVL) to keep the reservoir free from quagga mussels (MET, 2025).

The presence of quagga mussels in water sources is a water quality concern. Quagga mussels are an invasive species that was first discovered in 2007 at Lake Mead, on the Colorado River. This species of mussels forms massive colonies in short periods of time, disrupting ecosystems and blocking water intakes. They can cause significant disruption and damage to water distribution systems. MET has had success in controlling the spread and impacts of the quagga mussels within the CRA; however, the future could require more extensive maintenance and reduced operational flexibility than current operations allow. It also resulted in MET eliminating deliveries of CRA water into Diamond Valley Lake (DVL) to keep the reservoir free from quagga mussels (MET, 2025).

In addition, Golden Mussels, another invasive species capable of disrupting pipelines and altering ecosystems, were detected in the Sacramento–San Joaquin Delta in October 2024 and are now spreading through the SWP. These mussels pose similar concerns due to their ability to obstruct raw water conveyance facilities and negatively affect aquatic environments. Although their presence does not

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typically result in violations of drinking water standards, unmanaged infestations can degrade habitats, clog infrastructure, and reduce the aesthetic and recreational value of lakes and reservoirs. State and regional agencies continue to monitor golden mussel movement and evaluate appropriate response strategies to limit their spread (MET, 2025).

7.2.3.2 Groundwater
Groundwater is a reliable component of the water supply for Orange County, and OCWD manages the basin to provide long-term quality and sustainability. The basin supports a significant portion of the region's water demands and is monitored through an extensive network of production, monitoring, and recharge wells that provide data on water levels and water quality conditions across the aquifer system.

Orange County Groundwater Basin
OCWD is responsible for managing the OC Basin. To maintain groundwater quality, OCWD conducts an extensive monitoring program that serves to manage the OC Basin's groundwater production, control groundwater contamination, and comply with all required laws and regulations. A network of nearly 700 groundwater wells provides OCWD with a source for samples, which are tested for a variety of purposes. OCWD collects samples each month to monitor basin water quality. The total number of water samples analyzed varies year-to-year due to regulatory requirements, conditions in the basin, and applied research and/or special study demands. These samples are collected and tested according to approved federal and state procedures as well as industry-recognized quality assurance and control protocols (City of La Habra et al., 2017). OCWD routinely tests for hundreds of regulated constituents, but the parameters discussed, PFAS, TDS, and nitrate, are of focus because they represent the most relevant regional and regulatory considerations that influence groundwater management and long-term supply planning. These issues do not indicate that the groundwater basin is unsafe; rather, they are discussed because they are key focus areas for state agencies and water suppliers throughout Southern California.

PFAS are of particular concern for groundwater quality, and since the summer of 2019, the Division of Drinking Water (DDW) requires testing for PFAS compounds in some groundwater production wells in the OCWD area. According to the US Environmental Protection Agency (EPA), the established federal Maximum Contaminant Levels (MCLs) for certain PFAS compounds in drinking water include 4 nanograms per liter (ng/L), or parts per trillion (ppt), for PFOA and PFOS. In addition, the California State Water Resources Control Board has established health-based Notification Levels (NLs) and Response Levels (RLs) for several PFAS compounds. The current NLs are 4 ng/L for PFOA and 4 ng/L for PFOS, while the RLs are 10 ng/L for PFOA and 40 ng/L for PFOS. If PFAS concentrations exceed the NL, water systems must notify their governing body; if concentrations exceed the RL, water systems are expected to take corrective actions such as removing the source from service or implementing treatment.

PFAS have been detected in the OC Basin in very tiny amounts (parts per trillion), entering primarily via the Santa Ana River, whose flows infiltrate into the basin. Despite playing no role in releasing PFAS into the environment, OCWD is working with its cities and retail water districts to remove them from local water supplies in order to comply with new state and federal regulations. More than 100 wells have been impacted due to various state and federal regulations. Fifteen impacted agencies will have to temporarily purchase more costly imported water to replace PFAS-contaminated supplies. As of 2025, 53 impacted wells are back online due to close to a billion dollars being spent on state-of-the-art testing, research, and piloting of different treatment systems, and design and construction of treatment plants that are now