PUC, Fire Department Back Option 12 to Extend High‑Pressure Emergency Water to Sunset and Richmond

The San Francisco Public Utilities Commission and the San Francisco Fire Department told the Government Audit & Oversight Committee on Feb. 7 that a looped “Option 12” potable auxiliary water supply system (AWSS) offers the best combination of coverage and redundancy to protect the Sunset and Richmond neighborhoods after a major earthquake. The project was recommended after hydraulic modelling and an independent expert review showed the existing AWSS would not provide adequate post‑quake pressure for those West Side districts.

PUC presentation: findings and recommendation

John Scarpuolo of the San Francisco Public Utilities Commission said the city’s 2010 assessment of post‑earthquake firefighting capacity showed a citywide reliability score “of about 47%.” He told supervisors that PUC modelling of 12 options — seven expansions of the existing AWSS and five potable AWSS alternatives — found that only looped, redundant networks would meet the performance standards required by the fire department. “After the full completion of the projects that will be funded by the 2010 and 2014 EASER bonds, the citywide reliability will increase to 87%,” Scarpuolo said, citing the combined effect of past work and the recommended expansion.

Scarpuolo described “potable AWSS” systems as built to the same seismic standards and high‑pressure performance as the existing AWSS but designed so sections of the potable line can be isolated during firefighting to raise pressure. That design also creates the possibility of supplying potable water to West Side neighborhoods after a seismic event.

Scope, cost and funding

The conceptual Option 12 would be a larger loop providing stronger coverage in the Central and Southern Sunset and the Richmond and would include a line toward the Veterans Hospital. Scarpuolo said the PUC’s current estimate for designing and implementing Option 12 is about $109,000,000. PUC General Manager Harlan Kelly said he has already set aside $10,000,000 per year for four years — a $40,000,000 contribution — leaving an estimated funding need of about $70,000,000.

Independent review and redundancy concerns

Professor Charles Scawthorn, the independent reviewer retained to evaluate the AECOM analysis, told the committee that the report’s conclusions were reasonable but that more rigorous reliability work is needed. Scawthorn and other presenters emphasized the long‑term importance of multiple sources of supply: “Ideally, you would want to have multiple sources of supply in the Western part of the city, similarly to the Eastern part of the city,” he said, citing Lake Merced and a potential ocean/saltwater pump station as desirable additional sources.

Public and supervisor input

Supervisors pressed PUC and the Fire Department on whether Option 12 alone — fed only by Sunset Reservoir — provides adequate pressure and reliability for the Richmond. Professor Scawthorn and PUC staff said Option 12 would materially raise reliability but that a second source (Lake Merced or a saltwater pump) is highly desirable for long‑term resilience.

Public commenters, including retired SFFD assistant deputy chief Thomas Didier, urged the committee to prioritize a coastside/saltwater pump station and to add sources beyond Sunset Reservoir. Didier said using potable Sunset water as the primary firefighting source “is not a solution to fighting the multiple conflagrations that we will see in the Outer Sunset and the Outer Richmond.”

Next steps and committee action

PUC staff said they will complete a rigorous reliability analysis with the fire department, advance design for Option 12, analyze pipeline alignments, and begin environmental review and culturally competent outreach to affected residents and businesses. The committee voted to file the hearing at the meeting’s close; the motion to file passed without opposition.

Why it matters

The committee heard that about 42,000 structures on San Francisco’s West Side currently lack high‑pressure AWSS coverage and that the proposed work would materially increase the city’s ability to fight multiple, large fires after a major earthquake. Committee members and public speakers urged rapid progress on multi‑source redundancy and close attention to community impacts during design and construction.

What’s next

PUC and fire staff will complete additional reliability modelling, pursue environmental review with the Planning Department, and report back to supervisors as analyses and designs advance. The committee filed the hearing and will receive outcomes as projects move toward budgeting and implementation.