Ten days after reports circulated on the neighborhood-based social media network NextDoor that a home testing kit had detected pesticides in the Sunset District drinking water, city officials said Thursday that more rigorous testing has found no evidence of the chemicals.
“This was a $25 home test kit,” said Andrew Degraca, director of the water quality division at the San Francisco Public Utilities Commission. “It’s a colorimetric test, so you’re comparing two blue lines (to see) if one is darker than the other…so it’s a challenge. The method has limits.”
Degraca said home testing kits come with a lot caveats and are a “crude, preliminary type of test.” By way of comparison, SFPUC sent out more than 20 samples from around The City to a private laboratory in Southern California. Those tests cost approximately $1,200 each and meet more rigorous testing requirements.
The Sunset District resident who reported her findings to SFPUC was prompted to use the home test kit because of a “bad taste” in her water, she wrote on social media.
Degraca said the SFPUC frequently changes water sources, which may have accounted for the taste.
“We change our source of water all the time,” he said. “We think it was a source blend change that some customers picked up on. When you add the home test kits, social media and whatnot, it became a little more exciting than normal.”
SFPUC estimates they have spent approximately $50,000 responding to the incident but stressed that customers are an important part of the water monitoring system.
“If anyone has any concerns about water quality we encourage them to give us a call,” Degraca said, adding that 311 is the best way to make a report.