Nutrients: Let Your Voice Be Heard!


The San Francisco Bay Regional Water Quality Control Board (SF Regional Board) recently issued a tentative order on nutrients in treated wastewater that would have significant financial impacts for Bay Area wastewater customers, including Central San’s customers.

Chart showing proportional share of costs of nutrient limits

To meet the SF Regional Board’s proposed steep nutrient reduction requirements, the Bay Area’s wastewater utilities will need to spend more than $11 billion—costs that ultimately will be borne by wastewater customers. Central San customers alone would be on the hook for $665 million—or nearly $5,500 per household. And because the proposed requirements do not reflect the science to date, there is no assurance that these costs would have the intended benefit to the Bay.

Further, the short timeline precludes Central San’s ability to implement thoughtful, multi-benefit solutions, such as regional recycled water projects that would reduce nutrient impacts to the Bay while also increasing precious water supplies.

Let Your Voice be Heard

The SF Regional Board will hold a public hearing beginning at 9:00 a.m. Wednesday, July 10, 2024. Here’s what you can do to let your voice be heard:

1. Sign the petition, which will be presented to the SF Regional Board at the hearing. In addition, please share the petition link with friends, family, and co-workers throughout the Bay Area who also will be impacted by the SF Regional Board’s decision:

2. Attend the public hearing in person or remotely to make a public comment.

Attending the hearing in person: The hearing will be held at the Elihu M. Harris Building First Floor Auditorium at 1515 Clay Street in Oakland.

Attending the hearing remotely: To attend the hearing via Zoom teleconference, you must pre-register by no later than noon on Tuesday, July 9 (the day before the hearing). To register, complete the online registration form and select “Item 6” to indicate which agenda item you wish to speak on. The SF Regional Board Clerk will email you the link and passcode for joining the meeting. You do NOT need a Zoom account. Learn more about participating in the hearing remotely.

To view the meeting remotely, please use the following link to view the livestream.

Please ask the SF Regional Board to:

  • Grant a 90-day extension to the public comment period.
  • Conduct Bay Area listening sessions to ensure the public is aware of the proposed order and to hear community concerns before adoption. 
  • Follow the science to concentrate on where nutrient reductions will best benefit the Bay.
  • Develop a detailed financial analysis to determine impacts to Bay Area residents including disadvantaged, senior, and tribal communities.
  • Provide time and drive development of multi-benefit solutions that include both nutrient reduction and recycled water, and are worthy of the investment by Bay Area residents.


Wastewater contains nutrients such as nitrogen and phosphorus from human waste, food waste, and various soaps/detergents. Even when wastewater is cleaned to required standards, some nutrients remain. Nutrients also enter San Francisco Bay through runoff from stormwater, industry, and agriculture.  

Nutrients are essential to sustain life, but there is a balance. Too many can be too much of a good thing and may contribute to excessive algal growth in the Bay. The proposed regulations were triggered by a 2022 algal bloom in the Bay that killed thousands of fish. 


Central San cares deeply for the health of the Bay and is committed to reducing nutrients; however, we must let the science guide the regulations.

The proposed regulation looks at an acute dissolved oxygen (DO) threshold of 4 milligrams per liter (mg/L), below which is too little for fish. However, DO levels vary considerably throughout the Bay. The biggest nutrient challenges are in the South Bay, where DO falls below desired levels more than 90% of the time. This is evident in the maps below, where dark blue, such as the North Bay, is healthy Bay and yellow and orange are areas of low dissolved oxygen. 

Temperature map showing the dissolved oxygen levels throughout the Bay

Although not all regions of the Bay are equally impacted, the tentative order requires an across-the-board 40% nutrient reduction. Yet there’s no guarantee this would have any impact on water quality in Central San’s Suisun Bay discharge location. Based on the table data below provided by the SF Regional Board, Suisun Bay experiences a DO concentration <4 mg/L less than 1% of the time in every scenario. In short, Central San’s customers would face costs of $665 million with no discernable benefit to the Bay ecosystem.

Data table showing the dissolved oxygen levels throughout the Bay

Instead of a “one size fits all” solution, Central San believes we should follow the science to focus on the biggest nutrient problem areas to maximize the benefit to the Bay’s health and to Bay Area residents’ rate dollars.


Every dollar Central San spends to meet the proposed requirements comes directly from our customers. There is no Federal or State money to pay for this unfunded mandate, and these costs are NOT included in our current rates. If our customers are required to spend $665 million, we must ensure we’re implementing innovative, science-based, multi-benefit solutions that will improve regional water supply resiliency while also reducing nutrients.

Graphic showing the difference between Regional Board Proposal and Central San Proposal