Well Inventory Database

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DPR maintains the well inventory database (WIDB) of wells sampled for pesticides by DPR and other agencies. This database includes information about the well, the study name, the sampling agency, sample date, analysis date, analyzing laboratory, chemical analyzed, concentration reported, reporting limit, analytical method notes, 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 two million records in the database.

Historically, data from the database could be requested from DPR through a Public Records Act request. In an effort to make water quality data more easily accessible, a summary of the database is being made available online in both tabular and graphical formats using Google Fusion®. For well owner confidentiality, this data does not include the exact well location or the owners name and address. The WIDB data will be separated into three levels of increasing detail: Overview, Pesticide-Summary and Detection-Detail tables. Due to file size limitations in Google Fusion®, the data from the second level (Pesticide-Summary) has been further divided into three regions, North, Central, and South. Well locations will be listed by county, the county-meridian-township-range and section (CMTRS), the unique well key assigned to all wells in the WIDB, and a randomized latitude and longitude based on the CMTRS of the well. The three data level tables are: (these links will take you to a full description of the table)

  1. Overview: This summarizes all data for each well in the WIDB.
  2. Pesticide Summary: The regions (North, Central, and South) are based on counties within California. These three tables have a separate line for every pesticide tested for each well.
  3. Detection Detail: This has a separate line for each reported detection in the WIDB and includes DPRs evaluation of that reported detection.

How to Use Google Fusion®, PDF (1 mb)

Tables Listing the Letter Codes Used in the Tables, PDF (86 kb)

Information on Data Errors and Excluded Data, PDF (61 kb)


For content questions, contact:
Craig Nordmark
1001 I Street, P.O. Box 4015
Sacramento, CA 95812-4015
Phone: (916) 445-5393
E-mail: Craig.Nordmark@cdpr.ca.gov