From the Department of Pesticide Regulation:
The Department of Pesticide Regulation’s Groundwater Protection Program has posted the annual well sampling report to our website: https://www.cdpr.ca.gov/docs/emon/pubs/ehapreps.htm -> Report WIR2018, Sampling for Pesticide Residues in California Well Water – 2018 Update.
This report summarizes the results of groundwater sampling for pesticide residues from January through December 2017 by the Department of Pesticide Regulation (DPR) and the State Water Resources Control Board (SWRCB). The report also includes United States Geological Survey (USGS) data from 2011 to 2016 that had not been previously reported to DPR. Actions taken by DPR to prevent migration of pesticides to groundwater from nonpoint agricultural sources are also identified.