Kern County, California: drinking water report. Kern County – Bakersfield and the southern San Joaquin Valley – is home to about 910,000 residents in one
Kern County – Bakersfield and the southern San Joaquin Valley – is home to about 910,000 residents in one of the most agriculturally productive regions on Earth. Water comes from a mix of surface sources (Kern River, State Water Project) and groundwater from the San Joaquin Valley basin. The county's economy is tied to agriculture and oil production, both of which have direct impacts on water quality. Dozens of small water systems serve rural and unincorporated communities, many with limited treatment capacity.
Kern County faces water quality challenges that are unusual for most American counties. Naturally occurring arsenic in groundwater exceeds the EPA's MCL of 10 ppb in several community water systems, particularly in rural areas. According to the California State Water Resources Control Board, 15 public water systems in Kern County were in violation of arsenic or nitrate standards during the most recent compliance period.
Agricultural nitrate contamination is the other major concern. Fertilizer runoff has elevated nitrate levels in the shallow aquifer across large portions of the San Joaquin Valley. A 2012 UC Davis study estimated that over 250,000 San Joaquin Valley residents drank water exceeding the nitrate MCL – and Kern County was identified as one of the worst-affected areas. UCMR5 data also shows PFAS detections in some county systems, though at lower levels than in counties with military contamination sources.
Small and rural water systems in Kern County are the most vulnerable. State compliance data shows that systems serving fewer than 1,000 connections have the highest violation rates.
Check your water to see what your specific system is reporting. For arsenic and nitrate, reverse osmosis is the most effective household treatment. Our water filter guide covers which systems are certified for these specific contaminants. Pull your detailed report, and visit our California page for statewide patterns.