Bay Area residents told stinky water safe to drink

Drips that are ignored can add up quickly to hundreds of gallons of wasted water. Dripping tap Drips that are ignored can add up quickly to hundreds of gallons of wasted water. Dripping tap Photo: Getty Images Photo: Getty Images Image 1 of / 1 Caption Close Bay Area residents told stinky water safe to drink 1 / 1 Back to Gallery

Millions of Bay Area residents who aren’t enamored of the stinking water that has recently been coming out of their taps can rejoice — the musty smelling liquid won’t kill them or even make them sick.

That, at least, is what the experts say. And, as if that news wasn’t cause enough for celebration, San Francisco Public Utilities Commission officials said Thursday that they will immediately stop pumping the malodorous, algae-infused water into people’s houses.

“It’s nothing that’s harmful to humans, but it does have an earthy odor to it,” said Steve Ritchie, the commission’s assistant general manager for water. Therefore, “we will shift our water sources.”

The stink-water problem, which generated “a fair amount” of complaints, began Nov. 28 when district officials decided to draw down San Antonio Reservoir, in Alameda County, which was filling up fast with rain water.

The commission began pulling 30 million gallons a day from San Antonio, which is east of the Sunol Valley, and mixing it in with Hetch Hetchy reservoir water, which normally accounts for 85 percent of the water provided by the utility.

San Antonio is one of five reservoirs run by the commission, which serves 2.6 million customers in San Francisco, San Mateo and portions of Santa Clara and Alameda counties. The problem was, the reservoir was infused with blue-green algae, which injected a type of Actinobacteria known as geosmin into the drinking water. Geosmin is also known for giving beets an earthy taste.

Dozens of people began complaining about a musty aroma and odd flavor. Although blue-green algae can become toxic in high concentrations, San Francisco Department of Public Health officials assured water authorities that the amount of geosmin was not enough to cause health problems, Ritchie said.

“Normally this time of year, biological growth would be low because temperatures go down and algae doesn’t grow as much when it gets cold,” Ritchie said. “We don’t know why the algae is there. We just know it is there.”

Ritchie said the commission cut the flow from San Antonio on Thursday and began replacing it with water from the San Andreas and Crystal Springs reservoirs.

“We test the water throughout the system hundreds of times a day,” Ritchie said. “We are now going to add this compound on a more routine basis to the list of things we test at our reservoirs.”

Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com Twitter: @pfimrite