Annual Well Sampling Report
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 sheets contain 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.
- Pesticide Information and Use Fact Sheet, July 2021, PDF
- Pesticide Drinking Water Standards Fact Sheet, July 2021, 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.
|Report Year||Sampling Period|
| 2021 Update, PDF
|2020 and additional data from 2019|
|2020 Update, PDF||2019 and additional data from 2018|
|2019 Update, PDF||2018 and additional data from 2017|
|2018 Update, PDF
Appendix A, PDF
Appendix B, PDF
Appendix C, PDF
Glossary of Terms, PDF
|2017 and additional data from 2011-2016|
|2017 Update, PDF
Glossary of Terms
|2016 and additional data from 2015|
|2016 Update, PDF||2015|
|2015 Update||2014 and additional data from 2013|
|2012 Update||2011 and additional data from 2004-2011|
|2011 Update||July 1, 2010 - December 31, 2010|
|2010 Update||July 1, 2009 - June 30, 2010|
|2009 Update||January 1, 2008 - June 30, 2009|
|2008 Update||July 1, 2007 - June 30, 2008|
|2007 Update||July 1, 2006 - June 30, 2007|
|2006 Update||July 1, 2005 - June 30, 2006|
|2005 Update||July 1, 2004 - June 30, 2005|
|2004 Update||July 1, 2003 - June 30, 2004|
|2003 Cumulative Report 1986-2003||November 1, 1983 - June 30, 2003|
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