Features

SAN FRANCISCO — Voters will decide this November whether the aging system that delivers water to more than 2 million people in the Bay Area will get a much-needed seismic retrofit under a $1.6 billion bond measure city leaders placed on the ballot. 

With an 8-3 vote, the San Francisco Board of Supervisors approved a measure Monday that would help finance $3.6 billion of construction on Hetch Hetchy, a complex of aqueducts that supplies water to 2.4 million homes and runs more than 160 miles from Yosemite National Park to the San Francisco Bay area. 

An upgrade could prevent century-old aqueducts from collapsing in a major earthquake and leaving several Bay Area cities without their main source of water for as long as two months, according to scientists. The system’s pipes and tunnels cross three major earthquake faults — the San Andreas, Hayward and Calaveras. 

The system delivers water to 770,000 people in San Francisco and to 29 suburban wholesalers, which, in turn, serve about 1.7 million people in San Mateo, Santa Clara and Alameda counties. Seventy percent of Hetch Hetchy’s users don’t live in San Francisco, but in outlying cities such as Palo Alto, Mountain View, Redwood City, Fremont and parts of San Jose. 

However, the water system is owned and administered by San Francisco. 

If approved, the average four-person household in San Francisco would see its monthly water bill more than triple from an average of $13 to nearly $44 by 2015. Suburban rates would rise to an estimated $70 from its current average, $38.