Locations of Groundwater Protection Areas
DPR defines a Groundwater Protection Area (GWPA) as an area of land that is vulnerable to the movement of pesticides to groundwater by either leaching or runoff processes. DPR established one-square-mile sections of land as GWPAs if any of the following are true:
- previous detections of specific pesticides in that section
- contains coarse soils and depth to groundwater < 70 feet
- contains runoff-prone soils/hardpans and depth to groundwater < 70 feet
DPR restricts the use of specific pesticides in GWPAs, and the regulations and management practices differ depending on whether the GWPA is vulnerable to leaching or runoff. For more information on GWPA regulations and guidance, see pesticide use regulations to protect groundwater.
The table below provides lists of sections, maps, and shapefiles for counties that have GWPAs. Counties not listed have no GWPAs. Counties marked with * have new GWPAs effective January 1, 2020.
|Groundwater Protection Areas|
|Butte *||Colusa *||Contra Costa *||Fresno *|
|Glenn *||Kern *||Kings *||Los Angeles *|
|Madera *||Mendocino||Merced *||Modoc|
|Sacramento||San Bernardino||San Joaquin *||San Luis Obispo|
|Stanislaus *||Sutter||Tehama||Tulare *|
Statewide GIS shapefile showing all GWPAs in California. The zip file includes eight files that comprise the shapefile. These files should be unzipped and remain together in a single directory. The shapefile may be opened with a GIS software such as ArcGIS, QGIS, or Google Earth.
The Interactive California Pesticide Information Portal (CalPIP) is available to locate GWPAs.
The GWPA boundaries are based on the Public Lands Survey System. The following links provide a map of the statewide Public Lands Survey System used by DPR and downloadable PLSS GIS shapefiles of the townships and sections.
- Statewide Public Lands Survey System map, PDF showing California's counties, townships, and meridians.
- Downloadable PLSS GIS shapefiles of California's townships and sections.
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