SFPUC presents preferred plan to extend AWSS to Sunset and Richmond, estimates $109 million cost

John Scarpulla, manager of government affairs for the San Francisco Public Utilities Commission, told the Fire Commission on March 14 that engineers now recommend a potable AWSS network to provide both firefighting capacity and potable water resilience for the city’s West Side.

“We started at 47% in 2010. By 2020 or so, we’re gonna be at 87%,” Scarpulla said, describing modeling of a 7.8–7.9 earthquake scenario and a decade of work to upgrade reservoirs, pumps and pipelines that feed the AWSS. He said the potable AWSS would be built to drinking-water standards so, after firefighting, it could restore potable water to Sunset and Richmond neighborhoods even if the low-pressure city system had multiple breaks.

The SFPUC contracted an analysis of 12 options with AECOM. Of those, two later-stage designs (options 11 and 12) met the fire department’s performance standards; the agency recommended option 12, which extends looped pipeline coverage into central and southern Sunset and improves redundancy. Scarpulla said the conceptual price for the preferred option is about $109,000,000, of which SFPUC General Manager Harlan Kelly has allocated $40,000,000, leaving a shortfall of roughly $70,000,000.

Why the potable option: Scarpulla and Katie Miller, manager of the SFPUC City Distribution Division, told commissioners the West Side cannot be reliably served by expanding the existing AWSS without adding new supply connections—e.g., Sunset Reservoir or Lake Merced—or additional pump stations. Miller added that potable AWSS components can be paid by rate revenue when those elements provide drinking-water benefits, while high-pressure pumps needed strictly for firefighting would likely require general obligation or general-fund backing.

Commissioners pressed the presenters on schedule and funding. Scarpulla said design work is beginning now, pipes could start going into the ground in 2019 with construction continuing into 2023–2024 under current planning assumptions, and the team will pursue a mix of sources including the 2020 bond measure, other bonds, state and federal grants, developer contributions negotiated through development agreements, and SFPUC rate revenue for potable-related components. He warned that some elements—most notably the high-pressure pumps—are unlikely to be fundable through rates because they do not serve routine potable uses.

Commissioners also raised equity questions about how costs are allocated and whether West Side ratepayers would subsidize projects serving new development; the presenters described negotiations with developers aimed at ensuring fair contributions to off-site infrastructure where growth increases water demand. Scarpulla said the PUC has a federal resource team pursuing grants and had “about $600,000,000 in federal resources for water supply improvements” to pursue across several projects.

Next steps: Scarpulla said SFPUC and SFFD will perform rigorous reliability analyses and detailed design work, including choices of exact alignments and loop geometries, to meet the fire department’s standards. The commission did not take a vote on the AWSS recommendation; it heard the presentation and entered questions.