Lead Found in Half of California Drinking Water Samples: Study

Lead has been detected in over half of hundreds of tap water samples taken around the San Francisco, California area, according to a new study.

The study examined hundreds of drinking water samples in San Francisco, California, and discovered a “wide variety of contaminants” across three sources of water, including bottled water. Lead was among the 100 contaminants researchers tested for in samples of tap water, household-treated tap water and bottled water in the area.

Samples were taken between July 12 and July 28, 2022. Simple Lab, an environmental testing company in Berkeley, published the study in the PLOS Water journal on Wednesday.

The quality of American drinking water has recently come under question as the Biden administration pledges to reduce lead exposure throughout the country, and the U.S. Environmental Protection Agency (EPA) introduces legally enforceable limits for some per- and polyfluoroalkyl substances in water.

Researchers examined potential health risks associated with tap water, household-treated tap water and bottled water in the San Francisco area.

They examined 100 bottled water samples across 89 brands, 603 tap water samples and 111 samples of household-treated tap water. The study found contaminants with potential health risks across all three sources, with the highest prevalence in tap water and the lowest in bottled water.

Lead was detected in 51 percent of tap water samples, or 306 of 603 samples. It was also detected in 30 percent of household-treated tap water samples. Only one bottled water sample tested positive for lead.

“Lead is a persistent challenge due to aging infrastructure across the US, and exposure to lead can cause adverse neurological, developmental, learning and behavioral effects, especially in children,” the study said.

The presence of lead has heightened concern across the U.S., especially as schools nationwide have reported concerning levels in their water supply. In August, the Oakland Unified School District in California released details from districtwide tests that found lead levels above state limits in 6 percent of its water fixtures, such as drinking fountains. The water fixtures were unavailable to students and staff as the district remedied the issue.

The concerning discovery comes several months after the EPA announced an additional $3 billion from President Joe Biden’s Investing in America agenda to aid states and territories in identifying and replacing lead service lines. The project aims to prevent lead exposure in drinking water.

In 2023, the EPA released data showing Florida having the most lead service lines in the country, at 1.16 million lines, more than 12 percent of the state’s total number of service lines. Illinois, Ohio, Pennsylvania, Texas and New York also have a higher percentage of lead lines.

California, however, tested as one of the states with the lowest percentage of lead service lines, according to the EPA data. At that time, there were 13,476 lead service lines, accounting for .15 percent of the total service lines in the state.