Well Inventory Database

DPR maintains the Well Inventory Database (WIDB) of wells sampled for pesticides by DPR and other agencies. To make water quality data more accessible, a copy of the database is available online. This database copy includes information about the well, the study name, the sampling agency, sample date, analysis date, analyzing laboratory, chemical analyzed, concentration reported, reporting limit, legal agricultural use determination (point or non-point source determination), and the year the record was included in the database. Testing done for other water parameters (i.e., pH, salt, calcium) is not included in the database. There are over three million records in the database.

The WIDB has been upgraded and is now available in a new format. A detailed list of all columns, including new columns, can be found in the data dictionary below. More information about the WIDB and year-to-year updates or changes can be found in the Annual Well Sampling Report.

WIDB in CSV file format for sampling dates from August 1977 through December 31, 2023

This dataset does not include the exact well location for any wells sampled only by DPR; instead, the latitude and longitude data provided for DPR-sampled wells are the centroid of their respective Public Lands Survey System section. Data acquired from other agencies through California Safe Drinking Water Information System and the Water Quality Portal contain publicly available latitude and longitude and are included in this dataset if available. Additionally, all wells/samples, regardless of sampling agency, are identified by county, the county-meridian-township-range and section (COMTRS), and the unique well key assigned to all wells in the WIDB. The well owner’s name and address are not publicly available for any well in the database.

The following links are for the WIDB which contains over three million records. The complete statewide CSV file is available; however, it cannot be opened in Excel because the file exceeds Excel’s row limit. The data are also available in smaller CSV files separated by county that can be opened in Excel.

Data Dictionary, CSV

Complete Statewide File, CSV, August 1977 through December 31, 2023 (File exceeds Excel row limit)

CSV files separated by county for August 1977 through December 31, 2023:

Note about excluded data

Some records in the database are questionable and were excluded due to the following:

• Point Source Contamination due to pesticide spills near the wellhead, missing backflow protection devices, poor well construction, or monitoring wells surrounding pesticide application test-plot fields.
• Probable Laboratory/Sampling Agency reporting errors where DPR was unable to confirm or deny the validity of data submitted from outside agencies.

This affected 438 records, and the excluded data are available on request.

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

Version 2024.01 (2022 PUR Data Update)