$5.6M Penalty Approved for Delta Diablo Sewage Spill into Suisun Bay
Summary
The San Francisco Bay Regional Water Quality Control Board approved a $5,557,700 administrative civil liability settlement with Delta Diablo, a wastewater treatment agency serving eastern Contra Costa County. The penalty addresses a sewage spill that released more than 23 million gallons of untreated wastewater into marshland connected to Suisun Bay between November 5 and December 2, 2024. The spill originated from a subsurface break in the Shore Acres Force Main pipeline beneath marshland, which delayed detection. This is the largest penalty ever approved by the regional water board for a sewer spill.
“This $5.6 million administrative civil liability is the largest penalty ever approved by the regional water board.”
Wastewater treatment agencies operating force mains through sensitive marshland or tidal areas should evaluate their detection capabilities for subsurface pipeline failures. The penalty here was substantially influenced by the month-long delay in discovery — agencies with aging infrastructure in comparable settings may face similar scrutiny and liability if failures go undetected. The requirement to install parallel force mains for redundancy signals that regulators expect physical backup systems for critical conveyance infrastructure.
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GovPing monitors CA State Water Resources Control Board for new environment regulatory changes. Every update since tracking began is archived, classified, and available as free RSS or email alerts — 4 changes logged to date.
What changed
The San Francisco Bay Regional Water Quality Control Board approved a $5,557,700 settlement with Delta Diablo for a sewage spill that released over 23 million gallons of untreated wastewater into marshland connected to Suisun Bay. The spill began around November 5, 2024, and continued for nearly a month before discovery on December 2, 2024, originating from a subsurface break in the Shore Acres Force Main beneath marshland. Delta Diablo repaired a 20-foot pipeline section within two days, stopping the discharge by December 4, 2024.\n\nAffected parties include Delta Diablo and other wastewater treatment agencies operating aging infrastructure in sensitive environmental areas. The settlement requires installing a new force main parallel to the existing Shore Acres Pump Station pipeline to add redundancy, plus retrofitting the wastewater treatment plant's discharge outfall with duckbill check valves. The penalty calculation followed the State Water Resources Control Board's Water Quality Enforcement Policy, considering spill volume, response actions, and impacts to water quality and beneficial uses.
Penalties
Administrative civil liability of $5,557,700
Archived snapshot
Apr 28, 2026GovPing captured this document from the original source. If the source has since changed or been removed, this is the text as it existed at that time.
San Francisco Bay Water Board approves $5.6 million penalty for sewage spill to Suisun Bay
Penalty is largest for a sewer spill in the San Francisco Bay region
For immediate release
Date
2026-04-27
Category
Enforcement
Region
2
Contact
Blair Robertson – Information Officer
Press Room
1001 I Street, 24th Floor
Sacramento, CA 95814
Phone: (916) 341‑7365
Fax: (916) 341‑5252
Travel to the State Water Resources Control Board in the CalEPA Headquarters Building
Email: OPA@waterboards.ca.gov
OAKLAND – The San Francisco Bay Regional Water Quality Control Board has approved a $5,557,700 settlement with Delta Diablo, a wastewater treatment agency serving eastern Contra Costa County, in connection with a sewage spill that released more than 23 million gallons of untreated wastewater into marshland connected to Suisun Bay.
The spill began around Nov. 5, 2024, and continued for nearly a month before being discovered on Dec. 2. It originated from a subsurface break in the Shore Acres Force Main beneath a marsh, which delayed detection. Delta Diablo repaired a 20-foot section of the pipeline within two days, stopping the discharge by Dec. 4.
“Sewage spills of this magnitude pose serious risks to water quality, wildlife habitat, and public health,” said Eileen White, executive officer of the San Francisco Bay Water Board. “This settlement holds the discharger accountable while making critical investments to modernize infrastructure and reduce the risk of future spills.”
Sewage spills can introduce harmful bacteria and pollutants into waterways, posing risks to public health, recreation and wildlife habitat. This incident underscores the importance of continuous monitoring, regular inspections and proactive maintenance of wastewater infrastructure.
Most of the settlement funds will be used to install a new force main parallel to the existing pipeline at the Shore Acres Pump Station. This upgrade will allow for replacement of the aging pipe while adding redundancy and increasing operational flexibility.
Additional funds will support improvements at Delta Diablo’s wastewater treatment plant, including retrofitting the discharge outfall with “duckbill” check valves. These upgrades are expected to improve effluent mixing, reduce sediment and aquatic organism capture, and prevent flow reversal at the outfall
The regional water board calculated the penalty in accordance with the State Water Resources Control Board’s Water Quality Enforcement Policy. Factors considered included the volume of the spill, the discharger’s response and corrective actions, and the potential impacts to water quality and beneficial uses.
This $5.6 million administrative civil liability is the largest penalty ever approved by the regional water board.
More information about the regional board’s enforcement actions can be found here.
The San Francisco Bay Regional Water Quality Control Board works to preserve, enhance, and restore California’s water resources to protect public health, the environment, and beneficial uses for current and future generations.
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