Annual Well Sampling Report

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The Pesticide Contamination Prevention Act (PCPA) requires DPR to maintain a statewide database of wells sampled for pesticides. Public agencies that sample wells for pesticides must submit these results to DPR in a timely manner. DPR's Well Inventory Database, established in 1983, includes the well number, well type, well location, chemical analyses performed, sample date, sample type (initial or confirmation), analysis date, sample concentration and minimum detection limit (in parts per billion), and laboratory information. Agencies also may send information about well construction or the source of the potential contamination. DPR uses these data to evaluate and guide our groundwater protection monitoring and research activities. These data are used by academic institutions, governmental agencies, and the public.

The following fact sheet contains information about pesticides or degradates that the Groundwater Protection Program actively samples for or has sampled for in the past, including pesticide use and available human health advisory information related to drinking water standards. Not all information is available for all pesticides.

• 2023 Pesticide Drinking Water Standards and Information, July 2023, PDF

As required by law, DPR posts an annual report that includes statewide well sampling results collected by public agencies and describes the actions taken by DPR and the State Water Resources Control Board to prevent pesticides from migrating to the groundwaters of the state.

These files are in PDF format and download times may vary with the speed of your connection. (If you cannot open these files, you can download a free Acrobat reader).

Electronic versions of previous reports are available upon request at GWPP@cdpr.ca.gov.

For content questions, contact:
GWPP@cdpr.ca.gov