Proposed Basin Plan Amendment to Correct Errors in Freshwater Metal Water Quality Objectives, to Clarify the Basis to Establish Dilution Credits for Non-Priority Pollutants, and to Allow Establishment of Alternative Cyanide Dilution Credits and Mercury Concentration Triggers for Wastewater Treatment Operations

Background:

The San Francisco Bay Regional Water Quality Control Board (Regional Water Board) has adopted an amendment to the Water Quality Control Plan for the San Francisco Bay Basin (Basin Plan), which 1) corrects errors in freshwater objective calculation formulas for selected metals to be consistent with the California Toxics Rule (CTR) or National Toxics Rule (NTR); 2) clarifies that other applicable policies, regulations, and guidance aside from the State Implementation Policy (SIP) may be used when developing dilution credits for non-priority pollutants; 3) allows establishment of alternative cyanide dilution credits and mercury concentration triggers to accommodate water recycling projects or to reflect material and substantial changes in wastewater treatment operations and conditions; and 4) cleans up Table 3-4 to add clarifications and update obsolete information.

Silicon Valley Advanced Water Purification Center (Photo courtesy of Valleywater.org)

U.S. EPA Approval (Pending)

The Regional Water Board has requested to the U.S. EPA to review and approve the Basin Plan amendment. Once U. S. EPA approves the Basin Plan amendment, the changes will be incorporated into the Basin Plan and take effect.

OAL Approval

On July 22, 2024, the Office of Administrative Law (OAL) approved the Basin Plan amendment in OAL Matter No. 2024-0607-02S.

State Water Board Approval

At its April 17, 2024 meeting (under Agenda Item 3), the State Water Board approved the Basin Plan amendment via Resolution No. 2024-0013.

Regional Water Board Adoption

On December 13, 2023, the Regional Water Board adopted a resolution approving the Basin Plan amendment. The adopted resolution and final staff report can be found here:

Other supporting documents for the Regional Water Board adoption, including Staff Summary Report, Response to Comments, can be found on the Board meeting agenda page.

Other Related Resources

Water Quality Control Plan for the San Francisco Bay (Basin Plan)
California Toxics Rule
National Toxics Rule
The State Implementation Policy (SIP) for the California Toxics Rule
Federal National Pollutant Discharge Elimination System (NPDES) program

Subscribe to Our Mailing List

The Regional Water Board maintains email notification lists. To ensure you receive future information on this and other Basin Plan amendments, please subscribe to “All Basin Planning/TMDL” or “Basin Planning/TMDL Projects by Area” under “Basin Planning/TMDLs.” The instructions for subscribing to the list are provided on the subscription page, which you can reach by clicking here.

For more information contact:
Tong Yin, Ph.D., P.E.
Water Resource Control Engineer
San Francisco Bay Water Quality Control Board
1515 Clay Street, Suite 1400
Oakland, CA 94612
Phone: (510) 622-2418
E-mail: Tong.Yin@waterboards.ca.gov

(Page last updated 8/5/24)

Water is a precious resource in California, and maintaining its quality is of utmost importance to safeguard the health of the public and the environment.

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