Cities reach deal on drinking water

The San Francisco Public Utilities Commission has entered into an agreement with Daly City to collect and store reserve groundwater to hedge against future possible droughts.

The SFPUC called the cooperative-use agreement for the Westside Groundwater Basin, which the Daly City council approved on Dec. 13, a landmark accord that marked the first time two users of the Hetch Hetchy water system joined in an effort to store groundwater.

"This historic agreement will help protect San Francisco and the Peninsula against future droughts and water-supply shortages," said Susan Leal, general manager of the SFPUC, in a prepared statement.

Under the agreement, Daly City would essentially have more of its water piped in from Hetch Hetchy in Yosemite during normal or wet years when surface water is plentiful. Normally, the city pumps most of its drinking water from the Westside Basin, a strategy northern Peninsula cities historically use to augment their Hetch Hetchy supply.

By relying more on Hetch Hetchy water, the Westside Basin would be able to naturally replenish its supply and be available during droughts or emergencies. The basin extends from San Francisco's Golden Gate Park through the Sunset District and beneath Daly City, Colma, South San Francisco and San Bruno. It has the capacity to supply more than 150,000 households annually.