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The Department of Water Resources (DWR) provides Technical Support Services (TSS) to assist Groundwater Sustainability Agencies (GSAs) with the implementation of their Groundwater Sustainability Plans (GSPs) and other local entities to better understand groundwater conditions. These services support data collection, groundwater monitoring, and improved understanding of groundwater conditions to help advance sustainable groundwater management efforts across California.
Through the TSS program, DWR has partnered with GSAs and other entities on projects across the state to drill and construct groundwater monitoring wells, install groundwater level recording and telemetry equipment, perform downhole camera and geophysical surveys, and collect and analyze groundwater for general chemistry. The data and reports generated from these efforts are publicly available to support ongoing groundwater management and planning.
Additional information can be found on the Assistance and Engagement webpage.
Summary of Completed TSS Projects
To date, DWR has completed TSS projects in 35 groundwater subbasins, constructing 234 monitoring wells at 92 sites statewide. Each of these wells have been assigned a State Well Number (SWN), have had a Well Completion Report (WCR) submitted to DWRs Online System for Well Completion Reports (OSWCR), and have been registered either through the California Statewide Groundwater Elevation Monitoring (CASGEM) Online System or the Sustainable Groundwater Management Act (SGMA) Portal’s Monitoring Network Module (MNM).
Groundwater level data from these wells are collected by the GSA or DWR and submitted to CASGEM and/or the MNM. These data can be viewed on the Water Data Library (WDL).
WCRs for these wells can be found using the Well Completion Report Map Application.
A summary table of completed TSS wells including their associated well name(s), site code(s), SWN(s), and WCR number(s), can be viewed and/or downloaded here: DWR Completed TSS Wells
An interactive GIS map containing a feature set of all completed TSS wells can be accessed here: [GIS Map of Completed TSS Wells](https://www.arcgis.com/apps/mapviewer/index.html?url=https://services.arcgis.com/aa38u6OgfNoCkTJ6/ArcGIS/rest/services/DWR_Technical_Support_Services_(TSS)_Wells/FeatureServer&source=sd “GIS Map of Completed TSS Wells”)
The individual TSS well locations, associated borehole lithologic information, and groundwater level data can be viewed on the [SGMA Data Viewer](https://sgma.water.ca.gov/webgis/?appid=SGMADataViewer#gwlevels “SGMA Data Viewer”) by:
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Checking the “DWR TSS Wells” box under the “Groundwater Levels” tab on the left side of the screen.
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Clicking on any one of the well location symbols that appear on the interactive map.
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Clicking on one of the associated Site Code numbers that appear in the results table.
Completed TSS Projects by Groundwater Subbasin
Below is a list of subbasins in which TSS projects have been completed. These projects are organized by DWR Region ([Northern Region]( https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Groundwater-Management/Assistance-and-Engagement/Files/Basin-Points-of-Contact/NRO_a11y20250115.pdf “Northern Region”), [North Central Region]( https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Groundwater-Management/Assistance-and-Engagement/Files/Basin-Points-of-Contact/NCRO_a11y20230705.pdf “North Central Region”), [South Central Region]( https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Groundwater-Management/Assistance-and-Engagement/Files/Basin-Points-of-Contact/SCRO_a11y20241219.pdf “South Central Region”), and [Southern Region]( https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Groundwater-Management/Assistance-and-Engagement/Files/Basin-Points-of-Contact/SRO_a11y20250115.pdf, “Southern Region”)). Each subbasin listed below has one or more completed TSS project. As more TSS projects are completed, they will be added to this list.
All completed TSS projects have several associated documents and datasets, including a Well Installation Summary Report, TSS Agreement between DWR and the GSA, CEQA Notice of Exemption (NOE), Land Use or License Agreement, Local Drilling Permit, Composite Lithologic Log, Survey Report, and a Water Quality Analytical Report. Some projects also include downhole geophysical logs. These data and reports can be accessed by clicking on the subbasin below in which the project is located.
Northern Region
Antelope Subbasin
Big Valley Subbasin
Butte Valley Subbasin
Colusa Subbasin
Corning Subbasin
Enterprise Subbasin
Red Bluff Subbasin
Shasta Valley Subbasin
Sierra Valley Subbasin
Wyandotte Creek Subbasin
North Central Region
Cosumnes Subbasin
Eastern San Joaquin Subbasin
North Yuba Subbasin
Petaluma Valley Subbasin
Santa Rosa Plain Subbasin
Solano Subbasin
Sonoma Valley Subbasin
South Yuba Subbasin
Tracy Subbasin
Ukiah Valley Subbasin
Yolo Subbasin
South Central Region
Delta Mendota Subbasin
Kaweah Subbasin
Kern County Subbasin
Kings Subbasin
Paso Robles Area Subbasin
Tule Subbasin
Turlock Subbasin
Southern Region
Borrego Springs Subbasin
Cuyama Valley Subbasin
Indian Wells Subbasin
Indio Subbasin
Mound Subbasin
Oxnard Plain Subbasin
Pleasant Valley Subbasin
Organization: State of California
Last updated: 2025-07-23T19:55:55.658617
Tags: california-department-of-water-resources, monitoring, tss