San Francisco Fire Department Auxiliary Water Supply System

[1] The improved water system was originally proposed by San Francisco Fire Department chief engineer Dennis T. Sullivan in 1903, with construction beginning in 1909 and finishing in 1913.

The system comprises a collection of water reservoirs, pump stations, cisterns, suction connections and fireboats.

[6] The Ashbury tank is directly connected to the Twin Peaks reservoir and has a total capacity of 500,000 US gallons (1,900,000 L).

To supplement any failure of the pumping stations or reservoirs, the city’s two fireboats can be utilized to deliver salt water into the system.

As a final measure to counter a failure of the AWSS piping, the city maintains a network of 177 independent underground water cisterns.

Cistern in the Mission District, San Francisco, California
Blue-topped AWSS fire hydrant in the Mission district of San Francisco.
Twin Peaks Reservoir, at near-empty level.
Pumping Station No. 2
St. Francis fireboat
Brick circle denoting the underground location of a cistern