Basin Prioritization

DRAFT 2018 SGMA Basin Prioritization
Statewide Map of 2018 SGMA Basin Prioritization

Basin prioritization classifies California’s 517 groundwater basins (basins) into priorities based on components identified in the California Water Code Section 10933(b). The priority of basins determine the provisions that apply for the California Statewide Groundwater Elevation Monitoring (CASGEM) and Sustainable Groundwater Management Act (SGMA) programs in a basin. The prioritization process consists of applying datasets and information in a consistent, statewide manner in accordance to the provisions in the California Water Code.

DWR was first directed to prioritize basins as part of the Groundwater Monitoring legislation enacted in California's 2009 Comprehensive Water package. DWR prioritized groundwater basins through the CASGEM Program and released the results in 2014.

In 2015, SGMA went into effect and required DWR to prioritize basins for purposes of SGMA and to reassess the basin priority when DWR updates Bulletin 118 basin boundaries. In 2015, DWR implemented the 2014 CASGEM Basin Prioritization as the initial SGMA basin prioritization. In 2016, DWR received 54 requests for basin boundary modifications. DWR released the final groundwater basin boundaries, which incorporated numerous statewide jurisdictional and scientific modifications. On December 22, 2016, DWR published Bulletin 118 Interim Update 2016, which included the boundary modifications.

Finalization of the 2016 Basin Boundary Modifications documented in Bulletin 118 Interim Update 2016 required DWR to reassess the basin prioritization. In January 2019, DWR released the final basin prioritization for 458 of the 517 basins. The remaining 59 basins were affected by 43 basin boundary modification requests that were submitted between January and September 2018. The final basin prioritization for the remaining 59 basins will be released after basin boundaries are finalized.

2018 SGMA Basin Prioritization

The 2018 SGMA Basin Prioritization process and results are provided below.

Access the Results


 mapping-application Document  Open Data
Basin Prioritization Dashboard
(online web map)
Process and Results Document
2018 SGMA Basin Prioritization

Spreadsheets and data
at CNRA Open Data


View Statewide Map of 2018 SGMA Basin Prioritization

Timeline and Next Steps

The following table is the anticipated schedule for finalizing the 2018 SGMA Basin Prioritization.

Events Dates*
Prioritization based on 2016 Basin Boundary Modifications  
Public Comment Period Opens May 18, 2018
Webinar May 30, 2018
Public Meetings June 25-28, 2018
Public Comment Period Closes August 20, 2018
Finalize Prioritization (based on 2016 Basin Boundary Modifications) January 4, 2019
Prioritization based on 2018 Basin Boundary Modifications  
Release of Draft Prioritization  Spring 2019
Public Comment Period and Public Meeting Spring 2019
Release of Final Prioritization Late Spring 2019

  *Last modified on 1/4/2019. All dates are subject to change.


View Detailed 2018 SGMA Basin Prioritization Timeline Graphic

Public Meetings and Comments

DWR accepted public comments following the release of the Draft 2018 SGMA Basin Prioritization Process and Results.

View Submitted Public Comments    

Frequently Asked Questions on Basin Prioritization

Answers to frequently asked questions provided below or in the Frequently Asked Questions on Basin Prioritization document.

In January 2014, we conducted five workshops to introduce draft 2014 Basin Prioritization results and solicit public commentsFinal 2014 Basin Prioritization results are compiled into a summary table  available in PDF or Excel formatYou can also visit our Groundwater Information Center Interactive Map, a web-based application that includes a layer depicting Basin Prioritization information.

CASGEM BP 2014 Final Table
CASGEM Basin Prioritization 2014 Final Results ( XLSX) | (Publish Date:
Detailed spreadsheet of 2014 Final Basin Prioritization Results which includes values used in determining the individual component ranking values, organized by basin number.
CASGEM BP Process 2014
CASGEM Basin Prioritization Process 2014 ( PDF) | (Publish Date:
This report provides a detailed explanation of the Basin Prioritization Process and includes an appendix with figures and tables describing 2014 Basin Prioritization results.
CASGEM BP Brochure
CASGEM Groundwater Basin Prioritization Brochure ( PDF) | (Publish Date:
Brochure summarizing Basin Prioritization criteria and process.
CASGEM Basin Prioritization FAQ ( PDF) | (Publish Date:

The Water Code requires a statewide prioritization, to the extent that data are available, of California's groundwater basins using the following eight components (Water Code §10933):


  1. Population
  2. Rate of population growth
  3. Number of public supply wells
  4. Total number of wells
  5. Total irrigated acreage
  6. Degree to which persons overlying the basin rely on groundwater as their primary source of water
  7. Documented impacts on the groundwater within the basin, including overdraft, subsidence, saline intrusion, and other water quality degradation
  8. Any other information determined to be relevant by the department, including adverse impacts on local habitat and local streamflows

A priority designation of high, medium, low, or very low is assigned to each groundwater basin. For details on how changes in priority affect local agency compliance with SGMA, refer to establishment of Groundwater Sustainability Agencies (GSAs).