Tulare County, California: drinking water report. Tulare County in California's San Joaquin Valley has about 473,000 residents, with Visalia and Tulare as…
Tulare County in California's San Joaquin Valley has about 473,000 residents, with Visalia and Tulare as the largest cities. The county is one of the most productive agricultural regions in the world, growing everything from citrus to dairy. Water comes from groundwater wells and surface diversions from the Kaweah and Tule Rivers. Decades of intensive agriculture have fundamentally altered the groundwater quality beneath the valley floor.
Nitrate contamination is severe and widespread in Tulare County. According to the California State Water Resources Control Board's 2024 data, 42 community water systems in the county – more than any other county in California – have documented nitrate MCL exceedances. The sources are fertilizer application and dairy waste from the county's 1,600+ dairies. A 2024 UC Davis Community Water Center report found that small, disadvantaged communities in the county are disproportionately affected, with some systems unable to afford treatment.
The pesticide 1,2,3-trichloropropane (TCP), used historically as a soil fumigant, is another Tulare County groundwater contaminant. California's MCL for TCP is 5 ppt – one of the most stringent standards for any drinking water contaminant – and multiple county water systems have had to install granular activated carbon treatment to comply.
If you are on a small community water system in Tulare County, nitrate should be your first concern. Boiling water does not remove nitrate – it actually concentrates it. For households with infants, this is a health-critical issue because nitrate interferes with oxygen transport in young children.
Check your water for nitrate levels at your address. Reverse osmosis is the most reliable household nitrate removal method. Our water filter guide covers systems certified for agricultural contaminants. Pull your detailed report for local trends, and visit our California page for statewide data.