M EM ORAN DLJ M City of Poway
ADDITIONAL MATERIALS
(Agenda Related Writings/Documents provided to City Council or Staff after distribution of the Agenda Packet for the December 2, 2025 Regular City Council Meeting) DATE:
TO:
FROM:
CONTACT:
SUBJECT:
December 2, 2025
Honorable Mayor and Members of the City Council
Carrie Gallagher, City Clerk f
(858) 668-4535 or [email protected]
Item 7 - Resolutions Approving the Second Amended and Restated Regional Wastewater Disposal Agreement and Administrative Agreement No. 1 with the City of San Diego
Attached please find correspondence received after the agenda posting deadline.
Reviewed/Approved By:
Assistant City Manager
1 of 17
Reviewed By:
Alan Fenstermacher
City Attorney
Ap~
Ch~
City Manager
December 2, 2025, Item #7
From: Cathy Pieroni <cpieroni@cox .net >
Sent: Wednesday, November 26, 2025 7:05 AM
To: Eric Heidemann <EHeidemann@poway .org>
Cc: Chris Hazeltine <CHazeltine @poway .org>; Peter De Hoff <PDeHoff@poway .org> Subject: Item 7 - Regional wastewater agreement
EXTERNAL EMAIL
Good morning, Eric,
I hope you are doing well this holiday season. I scanned through Item 7 and have a number of questions based on my suspicion that Phase 2 of the Pure Water program is either significantly oversized or no longer needed. The attached document outlines my perspective on this issue.
As I understand it, San Diego has hired Stantec to evaluate nearly a dozen design options for Phase 2, including a Full Secondary option, and that analysis should be completed within the next 6 months. With that in mind, I have the following questions/concerns:
1. Is there a reason why this agreement can't wait to be signed until after the Stantec analysis is completed? What's another 6 months after all these years? So many of the terms in this agreement are based on a fixed 53-mgd sized Phase 2 project and would have to be amended if the project size changed. It seems likely that, at a minimum, the ww diversions from the East County's AWP project will be subtracted from the size of Phase 2. My back-of-the-envelope calculations suggest there's not enough wastewater going to Point Loma to even sponsor an additional 53-mgd of water purification due to conservation. So, why are we signing onto an agreement that doesn't recognize the change in circumstances and the need for adaptive management?
2. I do not understand why Metro JPA is agreeing to pay $1.8 billion to upgrade PLWTF if secondary equivalency doesn't pan out. That's a HUGE risk. Why not just put Phase 2 on hold until the legislation is chaptered into law? Or just upgrade Point Loma to secondary and skip Phase 2 altogether {which might not be as expensive as originally thought with today's low flows)? That is far less risky. I appreciate the political ramifications of delaying Phase 2. Unfortunately, those politics are driving forward a plan that just doesn't make sense anymore.
3. Btw, on page 2, the Council letter states that Pure Water will provide 1/3 of San Diego's future water supplies. That was the original estimate. But now, due to conservation, Pure Water will provide half of San Diego's future water supplies. Also on page 2 is a statement that Pure Water at 83 mgd represents cost savings over an upgrade to secondary at Point Loma. That may have been a reasonable statement back in 201 O when water demands were forecasted to keep growing instead of shrinking from the perspective of the city of San Diego. But, as you know better than anyone, that analysis does not measure the impacts that the project will have on the cost of water from SDCWA- as San Diego rolls off SDCWA, the price per AF of SDCWA's water will very likely 2 of17 December 2, 2025, Item #7
increase. So, Poway really needs to do its own analysis to determine what the cost advantages/disadvantages are from an integrated water/wastewater ratepayer point of view. It's all One Water now and so our decision-making metrics need to stop being bifurcated.
I appreciate that all the PAs and the City have signed off on this draft agreement, and no one wants to hold it up at this late hour. But unless there is a reason why it must be signed now, I th ink Poway's ratepayers will benefit from waiting until the size of Phase 2 is finalized and Poway completes its own independent ratepayer impact analysis.
Thank you for your consideration of my perspective on this.
Wishing you and your family and happy Thanksgiving! Cathy 2 3 of17 December 2, 2025, Item #7
Pure Water San Diego
Touching Base on Project Goals for Phase 2 Decision-Making San Diego's Pure Water Program has always been an impressive megaproject in concept. Pegged to produce 83 million gallons per day (mgd) of new water supplies in two phases, or 93,000 acre-feet per year (AFY), it is sized to produce roughly twice the amount of water as the Carlsbad desalination facility.
With Phase 1 about to come online and water rates set for the next two years and wastewater rates for the next four years, this is an appropriate time in which to contemplate Phase 2 of the Pure Water Program. While the Public Utilities Department (PUD) has hired Stantec to evaluate engineering design options for Phase 2. But by what measure(s) will Stantec measure relative value of the various options? Also, not all Program goals are engineering related.
This paper reviews the goals of the project in light of current conditions and trends.
San Diego's Goals for Pure Water
In this paper we explore the status of four stated goals of the Pure Water Program:
Water Supply Reliability
Secondary Equivalency
Affordability
PLWTF Capacity Limits
Other goals may exist and should be added to the final analysis. The main focus of this effort is to update any outdated assumptions for adaptive management of Phase 2 of a City project that clearly will have regional impacts.
Goal 1: Water Supply Reliability Status: Accomplished
The need for local supply development was first introduced in the City's 2002 Long-Range Water Resources (LRWR) Plan1 and the identification of a large-scale potable reuse project was 1 www.sandiego .gov/sites/default/fi1es/legacy/water/pdf/1rwrplan070604 .pdf 4 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
included in the 2012 LRWR Plan2. The stated goal in both plans was a reliable, safe drinking water supply into the future. Both plans referenced the insecurity of imported water supplies from the San Diego County Water Authority (Water Authority or SDCWA) as a main reason for the City to invest in local supply development.
It should be noted that the City's 2012 LRWR Plan predated the Water Authority's 2013 decision to invest in SO mgd of desalinated seawater at Carlsbad and the 2002 LRWR Plan predated the Water Authority's 2003 decision to invest its IID transfer (200,000 AFY), Canal Lining project (77,700 AFY), and the supersizing of San Vicente Reservoir. Not only did the City's LRWR Plans underestimate the reliability of Water Authority supplies, they also greatly overestimated the City's future demands. Projecting into the future, the analysis predicted the following City water demands would be as follows in the year 2030:
Forecast of San Diego-Only Future Water Demands
2002 LRWR Plan Est. for 2030 Demands 2012 LRWR Plan Est. for 2030 Demands l_ 297,000 AFY 274,600 AFY --- ---- - ---
In January of this year, the Office of the Independent Budget Analyst (IBA) presented estimates for 2030 water demands within the city of San Diego at a much more modest 172,284 AFY3.
In a little more than a decade, San Diegans have already reduced demands by more than a third (37%) - by about 100,000 AFY. This change in conditions should be reflected in the City's 2026 assessment of the need for, and the right size of Phase 2 of Pure Water. Shouldn't the analysis also recalculate the reliability of the Water Authority's proprietary supplies in meeting San Diego's supplemental water demands? According to its draft Long-Range Finance Plan, the Water Authority will be selling less water than it is obligated to purchase through at least 20354.
The graph on the next page demonstrates that the Water Authority has a surplus of supplemental water supplies even before Pure Water Phase 2 comes online . 2 www. sa ndiego . gov/sites/ defa u lt/fi les/lega cy/wate r /pdf /20121 rpwrfi na I report . pdf 3 www. sa ndiego . gov /sites/ defa u lt/fi les/2025 -01/25-02 -i ba-review-of-pud-s-fy-2 026-2 030-five-yea r-fina nci a 1-o utloo k-final. pdf 4 www.sdcwa .org/wp -content/uploads/2024/10/2025 10 23Forma1BoardPacket.pdf , page 35 of the pdf 5 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
SDCWA's Anticipated Water Sales Range
-100.000
350,000
- - - - - - - - - - - - ... - - - - - - - - - - - - - - - - - - - - - - 300.000
250,000
200,000
150,000
100.000
S0.000
2026 /.027 2028 :?029 :?020 203 l 2032 2033 203'! ?.035 Cctlendilr Ycilr
Between the City's and regional improvements in water-use efficiency, it's clear that San Diego has exceeded it water supply reliability goal and Phase 2 is not needed to be able to meet this first goal - at least for the foreseeable future.
While the City certainly has the right to develop more independent water supplies, let's be clear that it is for a different purpose other than securing water supply reliability after Phase 1 comes online.
Potential Unintended Consequences of Phase 2 on the Water Authority The chat above suggests that Water Authority sales could drop below 200,000 AFY if Phase 2 is completed. The Water Authority's system is not designed for such low flows and could face issues with water pooling in its giant pipelines. Stagnant water risks both hydraulic integrity of the system overall as well as generating water quality concerns. As a result, it is likely that the Water Authority would need to add CIP projects to downsize its system, most likely by relining vast sections of its five pipelines with smaller diameter pipes or by shutting down redundant sections of its system.
And who would be left paying for these additional costs? Those agencies that are not able to roll off the Water Authority would be stuck with the bill even though the expense is incurred as a direct result of those that are able to do so. Unfortunately, the Water Authority has no mechanism for assuring minimum sales to assure operational integrity and it's not likely to ever adopt such a policy with at least 61% of the weighted vote representing agencies that recently 6 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
developed local supplies. The following agencies all have recently invested in recycled water projects and would likely find it in their agency's financial best interests to avoid or minimize any minimal sales requirements or fixed charges.
Agency % Weighted Vote
City of San Diego
Helix Water District
City of Oceanside
City of Escondido
Padre Dam MWD
Side Bar on SDCWA Governance
42.260
6.937
5.579
3.623
2.867
61.266
Most California water agencies are governmental {non-profit) and either organized under municipal or special district articles governed by either a City Council or elected Board of 5 or 7 Directors, respectively.
The Water Authority is unique in having a cooperative style of governance in which each of its 22 retail water agencies is represented on its Board of Directors. The only other water agency with this style of governance is the Metropolitan Water District of Southern California {Metropolitan). Member agencies appoint their delegate{s) instead of being elected by the ratepayers. And despite having a fiduciary responsibility to protect the interests of the Water Authority {or Metropolitan), the delegates generally vote however best serves the interests of their parochial agency.
This puts both agencies at risk of self-destruction - their Boards of Directors have member agencies representing a majority of the weighted vote 5 benefitting financially from minimal commitments like fixed charges and, therefore, will not adopt policies to protect regional investments even when those investments were unanimously supported.
The Water Authority's weighted vote is calculated according to each member agency's proportional financial contributions 6 since its formation. To date, the city of San Diego's proportional purchases has mirrored its historic financial contributions, providing a good nexus for the balance of power. That's about to change, however, as Pure Water comes online. The City's weighted vote will dwarf its proportional current day investments in the Water Authority . 5 The Water Authority has a supermajority voting threshold of 55% that reverts to a simple majority threshold if the city of San Diego's representation ever fall to 38% or below. 6 Except for treatment costs.
7 of17 December 2, 2025, Item #7
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This imbalance is sure to cause renewed calls for changes in governance at the Water Authority (and possibly Metropolitan as well).
Since 2014, if not sooner, the region has worked diligently towards enacting federal legislation to define and authorize "secondary equivalency" as a standard approach for achieving regulatory compliance for its ocean discharge of water treated at the City's PLWTF.
The Pure Water program proposed a creative approach for finally providing San Diego with the legitimate pathway for regulatory compliance that had proven elusive to date. In short, a deal was made with local environmentalists that was formalized in an agreement in 2014. San Diego would divert a quantity of wastewater from PLWTF for purification that would have the de facto equivalence of achieving secondary treatment water quality objectives without having to actually upgrade PLWTF. In exchange, the environmentalists would support formalizing this "in lieu" approach in statute as "Secondary Equivalency".
It seemed a "win-win-win": San Diego would have regulatory certainty for its ocean discharges of wastewater without actually having to upgrade PLWTF to secondary treatment standards and San Diego would get a great quantity of new water supplies as an extra bonus -83 mgd.
While SDPUD has moved forward in good faith with the implementation of the Pure Water program, it has done so without securing "secondary equivalency" status. As of this writing, no such legislation has been chaptered into law and the PLWTF continues to operate under a modified provision.
In 2014, Representative Scott Peters introduced H.R. 4611: the Ocean Pollution Reduction Act !!, which needed to be reintroduced as H.R.1720: Ocean Pollution Reduction Act II in March of 2023. To date, H.R. 1720 has not advanced to the Senate.
We are in unprecedented times as relates to the federal government. Never before have federal forces been so inclined to eschew smart alternative approaches, such as Secondary Equivalency, if supporting them favors political rivals.
We must undertake an honest assessment of the risks of moving forward with a Secondary Equivalency strategy. Moving forward and investing billions of additional dollars in Phase 2 of Pure Water in faith that a legislative solution is forthcoming in the current political environment could be considered speculative.
8 of17 December 2, 2025, Item #7
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For example, could the City {and the Metropolitan Wastewater Joint Powers Authority {Metro JPA)) be at risk to upgrade PLWTF to secondary treatment, in addition to Pure Water, without having this legislation chaptered into law?
Policymakers should be satisfied that the risks of potentially never having Secondary Equivalency chaptered into law are manageable, even though it would mean that one of the stated goals of the program might not be achieved.
Why Did the City Commit to Building Pure Water at 83 mgd? As the PLWTF operator, the city of San Diego is the holder of the National Pollutant Discharge Elimination System {NPDES) permit for ocean discharge at PLWTF. The permit is issued jointly by the California Regional Water Quality Control Board, the San Diego Region {Regional Board) and the United States Environmental Protection Agency (EPA). Four prior NPDES applications (1995, 2002, 2007, and 2015) were approved based on modified secondary treatment requirements.
The EPA determined in each instance that the ocean discharges from PLWTF satisfied the water quality requirements under Sections 301(h) and 301(j)(5) of the Clean Water Act.
The 2022 NPDES application is scheduled to be decided on next month (December 2025). As drafted, a condition of this permit is the pursuit of 83 mgd of purified water, which is a negotiated term for the standardization of what is called 'Secondary Equivalency' - an in-lieu alternative to actually upgrading PLWTF to Secondary Treatment standards.
The PLWTF is the last remaining wastewater treatment plant in the United States to upgrade its treatment technologies to achieve the water quality metrics identified in the Clean Water Act for "Secondary" treatment. In addition to insufficient treatment capabilities, there were concerns as recently as 2017 that without the Pure Water program, the portion of Metro System flows directed to Point Loma WTF during inclement weather periods, when no recycled water use occurs, would approach 240 mgd - its maximum treatment capacity. 7 Section 301{h) of the CWA allows the United States Environmental Protection Agency {US EPA) and individual states to issue permits for discharges not achieving full secondary treatment so long as certain criteria are met. In simple terms, the discharger must show that its less-than secondary discharge is not violating state or federal water quality standards, or negatively affecting species diversity and abundance in receiving waters and sediments. 7 www.epa.gov/sites/default/files/2017-08/documents/ca0107409-point_loma_301h_decision_and_tdd_2017-08-
04.pdf, page 19 of the pdf.
9 of 17 December 2, 2025, Item #7
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The Clean Water Act defines compliance for ocean discharge in terms of only three wastewater constituents: Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS) and pH.
BOD is a measure of how much organic material in the wastewater can be broken down by microorganisms. It measures the potential for the discharge to deplete oxygen in the receiving water. TSS is a measure of the nondissolved particles in the wastewater. And, pH is the acidity of the wastewater
Specifically, secondary equivalency for PLWTP under the Pure Water strategy would achieve the following water quality improvements, consistent with regulatory requirements for standard secondary treatment of a facility treating up to 240 mgd8:
• annual cap on TSS of 9,942 mt/yr by 2027, with prior incremental reductions, allowing for build out of the advanced water purification system to off-load PLWTF treatment; • concentration limit on TSS of 60 mg/I, calculated on a 30-day average; • minimum removal rates of 80% for TSS and 58% for BOD, consistent with current NP DES permit;
• current Clean Water Act standard for pH and other effluent limitations of secondary treatment;
The production of 83 mgd was added as the final agreement point. Why 83 mgd? Why not 82 or 84 mgd?
Basically, the number was backed into based on 2010 assumptions related to how much water would need to be diverted to achieve the water quality objectives listed above, assuming high flows into Point Loma (up to 240 mgd, its rated capacity).
The reasoning went as follows: by diverting wastewater away from PLWTF to Pure Water, less treated wastewater would be discharged into the ocean. If enough wastewater was diverted, then an equivalency to secondary treatment would be achieved. Less discharged water equals less pollution.
Wastewater Diversions (mgd)9
Phase 1 (30 mgd new water)
Phase 2 (53 mgd new water)
Total
8 www.sandiego.gov/sites/default/files/volume i e xecutive summary.pdf. 52 92
144 I
9 www.sandiego.gov/sites/default/files/volume i executive summary.pdf, page 17 of the pdf states that 52 mgd of wastewater will be diverted for Phase 1- a factor of 1.73 times the water produced. I've applied a factor of 1.73 to other projects as estimates.
10 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
The production of 83 mgd of new water supplies would reduce wastewater discharges by an estimated 144 mgd - a little more than half of the facility's rated capacity.
But what if we were able to achieve equivalent reductions in discharges through a combination of potable reuse projects (Pure Water Phase 1 and the East County's AWP project 10) along with our amazing water conservation achievements?
The graph below demonstrates flow trends into PLWTF through 2017. Clearly, the conservation story seen on the water side of operations includes indoor conservation as daily average flows have reduced from a high of 194 mgd in 2001 to 139 mgd in 2017 (28%) while population in the Metro area increased by 16 percent between 1995 and 201511. 250
200
150
100
50 0
PLWTF Avg Daily Flow (mgd)
I T ds Back in 2010 . ...:on of Forecasted F ow ren Approx1rna" ----
Actual Flow T rends •
- - - - since 1998
--- --
- "' .. - . .
m ffi m m m m m m m ci ci ci ci O O ci ci ci ci ci ci ci ci ci O O ci rl rl rl rl rl rl rl rl rl N N N N N N N N N N N N N N N N N N Source: www.sandiego.gov/sites/default/files/2017 point loma annual reports.pdf , page 32 1010 Led by Padre Dam Municipal Water District (MWD), the East County Advanced Water Purification (AWP) Program is finishing up construction and will soon produce up to 11.5 mgd of new drinking water supplies. Source wastewater supplies for this project are diverted from PLWTF. 11 www.epa .gov/sites/default/files/2017-08/documents/ca0107409-point lama 301h decision and tdd 2017- 08-04.pdf, page 33 of the pdf.
11 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
Using another data source12 for average daily flows between 2018 and 2024 and estimating flows through 2030, with Pure Water Phase 1 and East County AWP projects coming on line in 2028, daily flows at PLWTF may diminish down to 78 mgd. Final estimates should be presented by PUD staff.
PLWTF AVG DA IL Y FLOW {MGD)
ACTUAL A ND ESTIMATED
00 00 CO
r-- r-- r--
111
oo m o rl N m ~ ~ ~ ~ oo m o rl N m ~ ~ ~ ~ oo m o rl N m ~ ~ ~ ~ oo m a m m O O O O O O O O O O rl rl rl rl rl rl rl rl rl rl N N N N N N N N N N m m m o o o o o o o o o o o o o o o o o o o o o o a a a o a o o o o rl rl N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N If, in fact, average daily flows to PLWTF do reduce to less than 80 mgd in 2030, then that suggests that there is insufficient wastewater to produce an additional 53 mgd of purified drinking water supplies as anticipated for Phase 2. It is estimated that 92 mgd of wastewater would be needed to produce 53 mgd of purified drinking water. Having sufficient wastewater is a concern even if Phase 2 is downsized to account for the East County JPA's project .
Metro JPA and Council should receive an update on all conditions or circumstances that have reduced flows to PLWTF, such as those listed above, and evaluate the "right" size of Phase 2 of the Pure Water Program.
The presumed advantage for seeking the "right-sizing" of Phase 2 is affordability - a smaller project should be less expensive to construct and operate.
Dark Horse Option: Full Secondary
There is another potential option - upgrade PLWTF to full secondary and abandon Phase 2 of the Pure Water Program. The original analysis is decades old and prior to knowledge about reduced flow trends. If the reduced flows allowed for the capacity of PLWTF to be downgraded 12 https://emma .msrb .org/P21917109-P21465627 -P21914873.pdf, page 4 of the pdf. It should be noted that the average daily flows to PLWTF in this report disagree with those sourced up through 2017 for the data overlap years of 2015-2017 in both reports . Avg flows are higher in th is report than the previous one. 12 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
from 240 mgd to, say, 200 mgd, could a portion of unused campus space be more easily be converted to pre-treatment of some other technology at a lower cost? Full secondary treatment at PLWTF, if affordable, offers multiple benefits:
• Standardized application for NPDES permit
• Various court mandates go away
• Addresses risk that Secondary Equivalency may not be chaptered into law anytime soon
It should be noted that a Full Secondary option at PLWTF in lieu of Phase 2 of Pure Water would be borne entirely on wastewater rates and charges whereas the costs of Pure Water Phase 2 are split between water and wastewater . From an integrated water/wastewater cost to the ratepayer, it might be the more affordable option, however.
PUD staff recently reported to Council that the cost of SDPUD's water would be favorable to the cost of water purchases from the San Diego County Water Authority (Water Authority or SDCWA).
While that may be the case under the scenario in which PUD pursues the full 83 mgd of Pure Water production, it's important to understand that the act of creating new local water supplies is inflating SDCWA water rates. This inverse relationship between SDCWA water sales and its rates is expressed even more dramatically when SDCWA's annual water sales fall below 327 TAFY - the amount of water that it is obligated to purchase.
When the Water Authority is able to sell more water, it can spread its costs over more units sold. As the City buys less water, it causes the Water Authority's rates to increase at a higher rate since there are fewer AF of water sold over which to spread its fixed costs. In October 2025, Water Authority staff presented a range of forecasted of future water rates.13 That range is entirely dependent on water sales.
The Water Authority just presented a draft of its Long-Range Finance Plan. Over the ten-year period of 2026-2065, the compounded annual growth rate (CAGR) of its volumetric rates is estimated to escalate between 5.5% to 9.5%, depending on water sales volumes. 13 www.sdcwa .org/wp-content/up loads/2024/10/2025 10 23FormalBoardPacket.pdf, page 40 of the pdf. 13 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
SDCWA's Anticipated Range in Water Rates
Chart l-8: Projected Volumetric Water Rate Range
$6,000
$5 ,000
s,,.ooo
0 ~
~ S3,000
u
~
(/)
$2,000
$1 ,000
S·
2026 2027 2028 2029 2030
C11lt::ndt1r Year-End
2031
Volum etr ic HJlc s {•.vllh T1c,:mn enl) 1ang:::
2032 2033 203~ 2035
So, when comparing the cost of water supplies between Pure Water and SDCWA, it's important to not just recalculate SDPUD's water rates for each of the scenarios presented. It's also important to recalculate the Water Authority's rates and charges for each scenario according to how much water will be locally produced vs. purchased from the Water Authority since Phase 2 has the potential to reduce Water Authority sales by as much as 59,400 AFY {53 mgd) - 21% of the Water Authority's estimated sales volume in FY 2026.
An additional metric for measuring affordability would be an integrated water/wastewater comparison - the total impact the ratepayer would experience.
As we saw in the previous discussion, Average Daily Flows at PLWTF are set to reduce below 100 mgd by 2030- less than half its rated treatment capacity of 240 mgd. However, another metric must be evaluated in determining how well we're doing: Peak Daily Flows. 14 of 17 December 2, 2025, Item #7
Pure Water Adaptive Management
While the City's stormwater system is separate from its sewer system, incidental storm flows will find their way into the sewer system through manhole covers and the like. During rain events, flows into PLWTF has surged beyond its rated 240 mgd treatment capacity.
The following charts from 2005 demonstrate the impact that a storm can have on flows to Point Loma.
,-._
]50
J)j
(
JOQ
2i5
~ 250
= - 215
~
_:: 200
..
175
150
125
----- ....
-----
Point Loma Wastewater Treatment Plant
2005 Daily Flows (mgd)
...
\
I
100 ~------------------------
In 2005, the maximum daily flow reached 324.6 mgd - well above the rate capacity of the facility of 240 mgd. This peak daily flow corresponded with rain events seen in the following graph.
2.4 j 2 .2
t i1 ,1 .6
j 11 .4
~ t .;z
5- 1'
w 0.8
~ 0.6
1 0.4
:> 0 .2
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,
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,
San Diego Precipitation -2005
Dailv Rainfall - Lindberah Field
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Months
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December 2, 2025, Item #7
Pure Water Adaptive Management
In November 2018, the City of San Diego entered a Consent Decree with San Diego Coastkeeper and Coastal Environmental Rights Foundation, which outlines obligations to reduce pollutant concentrations in stormwater discharged from Point Loma Wastewater Treatment Plant (PLWTP} to below specific numeric levels. As part of this consent decree, the City is capturing flows from the 40-acre Point Loma campus and routing it into the wastewater treatment facility prior to being released (discharged} into the receiving waters of the Pacific Ocean.
Information regarding the anticipated increases in peak daily flows would be attributable to new stormwater capture requirements at PLWTF. More information from PUD staff is needed.
From the perspective of Average Daily Flows, it seems that the City will have accomplished its fourth goal with Pure Water Phase 1. More data is needed to determine if Phase 1 similarly addresses Peak Daily flows requirements under the new consent decree.
Conclusion
Water management is an increasingly complex pursuit, especially in Southern California. Just when we think we've identified "normal" water use patterns from which to forecast future demands for water, they inevitably change. Thus, the need for adaptive management.
When evaluating how well the City has done in addressing its four major goals for Pure Water, it becomes evident that much progress has already been made and where additional analysis is needed. The following table provides a brief summary of the four goals identified in this paper.
Goal Accomplished to Date Still Needed
1. Water Supply
Reliability
2. Standard NPDES
Permitting
16 of 17
The City and the region have
strong water supply reliability
without Phase 2
Bills have been introduced but
have not been chaptered into
law
Comparison of future SDCWA
water rate costs compared to
full 83 mgd of Pure Water
Analysis on the "Right Size" of
Phase 2 is needed, including
Full Secondary Option
Current day analysis of the
viability of this legislation with
current administration
Comparison of multiple
scenarios against the cost of
SDCWA's water, including a
dynamic assessment of SDCWA
rates depending on how much
water the City buys.
December 2, 2025, Item #7
Pure Water Adaptive Management
4. Addressing
PLWTF Capacity
Limitations
By 2030, average daily flows
should be well below 240 mgd
(less than 100 mgd)
Additionally, the cost of Phase
2 Options should be presented
in terms of the impact to the
ratepayer - an integrated water
and wastewater cost to the
typical residential customer on
their bill
More analysis is needed
regarding peak daily flows
given new stormwater
requirements
Additionally, the following questions and concerns arose in this paper, requiring additional consideration (perhaps paired with additional goals):
1. Are the flows to PLWTF sufficient to support Phase 2 sizing of 53 mgd?
2. As local agencies roll off the Water Authority, will water flows reduce to a level requiring the "replumbing" of the Water Authority's aqueducts at higher costs than would have otherwise occurred if it hadn't been for the development of local supplies? If so, which agencies are responsible for these costs?
3. In 2024, the City purchased 38 percent (112,360 AF) of the Water Authority's annual water sales14, which is roughly equivalent to its percentage of the weighted vote (42.26%) it has on the SDCWA Board of Directors. Pure Water is supposed to produce 93,000 AFY. Assuming that future demands for water remain flat, after Pure Water comes on line the City would be purchasing less than 20 TAFY from the Water Authority.
The dominance of the City's percentage of the weighted vote would diminish organically over time and eventually the majority of the weighted vote would be held by those agencies buying SDCWA's water. Presumably, those agencies would adopt policies that increase the share of revenues collected on fixed charges, adding unanticipated regional costs on top of the City's cost to maintain Pure Water. The City should consider the erosion of its percentage of its weighted vote at the Water Authority as a consequence of pursuing a strategy for water supply independence.
14 www.sdcwa.org/annualreport/2024/connect.php#wrp
17 of 17 December 2, 2025, Item #7