Water rationing: How low can SF go?

Hetch Hetchy Reservoir

From an op-ed in the Chronicle:

Do you think you could reduce your water use by 40 percent? What if we asked for even more than that? This is the type of rationing we can expect during a severe drought if a new proposal from the State Water Resources Control Board is implemented.

The San Francisco Public Utilities Commission is the retail water provider for San Francisco and the water provider for 26 wholesale customers in San Mateo, Santa Clara and Alameda counties. Today, 85 percent of the water we deliver to our customers comes from the Tuolumne River. The state water board’s newly released draft update to the Bay-Delta Plan to balance California water uses — drinking, irrigation and fisheries — has potentially serious effects for the 2.6 million people who rely on our water system. It recommends diverting less water to increase the flow on the Stanislaus, Tuolumne and Merced rivers in the range of 30 to 50 percent of unimpaired flow from February to June...

Customers throughout the commission’s service area are already some of the most efficient water users in California (see below). Despite outperforming nearly every other place, this proposal means we would have to fundamentally rethink where we get our water in drought years and how we consume that water. We can’t conserve our way out of this. Water is our lifeblood. The consequences of these cutbacks potentially could cripple our Bay Area economy...

Comparing water use in S.F. and California

Average residential use (weighted to take into account population):

41 gallons per day, San Francisco water users

54 gallons per day, SFPUC service area water users (includes customers in Alameda, San Francisco, San Mateo, Santa Clara counties)

82 gallons per day, statewide average

Source: San Francisco Public Utilities Commission, State Water Resources Control Board

Wasting water in the Central Valley