The Great 1906 San Francisco Earthquake and Fire was one of the greatest natural disasters in recent history. Approximately 3,000 deaths and 28,000 buildings were lost, resulting in $524 million in property loss in 1906 dollars. There was insufficient water available to fight fires as over 300 water main breaks occurred. The earthquake and fire highlighted the need for a dedicated water supply system for firefighting in the City.
The Emergency Firefighting Water System (also known as the Auxiliary Water Supply System or AWSS), was built in 1913 as an independent high-pressure water supply system dedicated to fire protection. At a cost of $5.2 million dollars, the system consists of a 135-mile pipeline network, a high elevation reservoir, two large capacity tanks, two pumping stations, fire boats, cisterns (underground water storage tanks), and Bay water intakes (suction connections). The system has unique capabilities, including the ability to deliver water at much higher pressures and the ability to use unlimited water from the Bay.
Constructing the Twin Peaks Reservoir, a main water supply for the Emergency Firefighting System. 
Dewatered Twin Peaks Reservoir to assess its condition. 
Reliability improvements to Twin Peaks Reservoir completed.
In 2011, the SFPUC assumed responsibility for the Emergency Firefighting Water System to make long-lasting seismic and operational improvements. The upgrades to the City’s Emergency Firefighting Water System will help prepare San Francisco for multiple-alarm fires, natural disasters and the unpredictable.
Since 2012, seismic, operational and security upgrades have been made to several core facilities along with the installation of 30 new cisterns that will provide an emergency source of water for firefighting.
SFPUC 