This Well Completion Report geospatial dataset represents an index to a subset of records available from the California Department of Water Resources' (DWR) Online System for Well Completion Reports (OSWCR). This version of the release contains data from 262,649 well completion reports (WCRs) for water supply wells from Amador, Butte, Calaveras, Colusa, El Dorado, Glenn, Kern, Kings, Merced, Monterey, Nevada, Placer, Riverside, Sacramento, San Benito, San Bernardino, San Luis Obispo, San Joaquin, Santa Clara, Santa Cruz, Shasta, Stanislaus, Sutter, Tehama, Tulare, and Yuba counties in California. A subset of WCRs for 5969 wells that are not water supply wells also are included. The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) did studies of water quality in groundwater resources used by domestic wells in parts of those counties in 2012-2023, and these data were compiled as part of those studies. Ninety-two WCRs from the additional California counties of Trinity, Ventura, Alameda, San Diego, Sierra, Orange, Lassen, Sonoma, Inyo, Tuolumne, Mariposa, Los Angeles, Fresno, and Madera have been included because the WCRs were initially incorrectly assigned to one county and are now reported with their correct county assignment. This dataset differs from the data provided in OSWCR because it includes data for some additional fields such as NumberOpenIntervals, USGS_SiteNumber, and SWRCB_DDW_PublicSupplyWell and doesn't include some fields that are in OSWCR, some data attributed in OSWCR were checked for accuracy and updated, and more precise locations were determined for some wells. The additional fields provide more detail about the open or perforated intervals in the well, various identification numbers for the wells, and generalized lithology, and were populated where they could be identified. Some attributes have been provided by cooperating entities as indicated in the REFERENCE field. About 60 percent of the locations are georeferenced to finer resolution based on county Assessor's Parcel Number (APN), 911, or local water authority geospatial datasets. The attributed information is linked to the redacted publicly available Department of Water Resources well completion report image when the link can be resolved. This dataset is for information purposes only. All attribute values should be verified by reviewing the original Well Completion Report. California Water Code Section 13752 allows for the release of redacted copies of well completion reports to the public. DWR is the authoritative source of these data. https://data.ca.gov/dataset/well-completion-reports Version History Summary: Version 1.0 posted online August 8, 2019 (available upon request) Version 2.0 posted online January 24, 2023 (https://doi.org/10.5066/P9R1V41Q) Version 3.0 posted online July 21, 2023 (available upon request) Version 4.0 posted online September 24, 2024