Napa County Groundwater Sustainability Agency (GSA)

The 2014 Sustainable Groundwater Management Act (SGMA) provides a framework for sustainable management of groundwater resources by local authorities. The act provides a timeline  – 20 years – to implement actions that achieve long-term groundwater sustainability. It protects existing surface water and groundwater rights and does not impact current drought response measures. The California Department of Water Resources (DWR) is in charge of the SGMA Program and has developed guidelines for local agencies to follow. DWR has also developed a SGMA website to explain the requirements under the Act. 

DWR completed its evaluation and re-prioritization of all of the groundwater basins across California, which was finalized in January 2019. The Napa Valley Subbasin was reprioritized from a medium to a high priority ranking due primarily to revised projections of future population for the Subbasin, an increased assessment of the total number of wells, and a revised approach to evaluating water quality in the Subbasin. The change from a medium y to a high priority does not affect current requirements for the Napa Valley Subbasin under SGMA. DWR has noted that the Napa Valley Subbasin is being managed sustainably and it is not in overdraft.

The Napa Valley Subbasin (map) is the only basin in Napa County with a priority ranking by DWR that is subject to SGMA at this time.

Groundwater Sustainability Planning

In accordance with SGMA and adopted GSP regulations, Napa County submitted an alternative GSP (Napa Valley Groundwater Sustainability: A Basin Analysis Report for the Napa Valley Subbasin) to DWR on December 16, 2016. On July 17, 2019, DWR sent a notification letter PDF  and staff report  to Napa County outlining DWR’s preliminary recommendation to not approve the County’s alternative GSP.

DWR’s staff report did not consider and does not conclude that the Napa Valley Subbasin is, or has been, managed unsustainably. DWR’s preliminary staff recommendation centers on the evaluation that Napa County did not establish and operate the subbasin to thresholds or objective management criteria for a period of at least 10 years prior to the adoption of SGMA. On October 11, 2019, Napa County provided a response  to DWR to address their questions and other requested clarifications regarding the alternative GSP.

On November 13, 2019 DWR notified Napa County that it had finally completed its review of the County’s Alternative GSP and the County’s responses . While recognizing that Napa County is proactively managing groundwater, DWR nonetheless elected not to approve the County’s Alternative GSP. DWR’s decision was not a judgment on the health or management of the basin, as noted in DWR’s findings. In fact, DWR clarified that its decision was not an indication that the Napa Valley Subbasin is being managed unsustainably, but rather commended the County for proactively managing groundwater. Please see DWR’s SGMA Portal for Alternatives and Reporting for additional information.

As a result of DWR’s decision, a Groundwater Sustainability Agency (GSA) was required to be formed for the Napa Valley Subbasin  in order to be in compliance with SGMA and DWR regulations, otherwise the Subbasin would be deemed "unmanaged." If a GSA is not formed, the State Water Resources Control Board (SWRCB) would be obligated to step in to monitor and manage the Subbasin and groundwater users. The SWRCB could require all groundwater users within the Subbasin to install meters, report extractions, and pay fees to cover State costs.

On December 17, 2019, the Napa County Board of Supervisors conducted a public hearing under Water Code section 10723 and adopted a resolution affirming Napa County’s intention to manage groundwater in the Napa Valley Subbasin and to form the Napa County Groundwater Sustainability Agency pursuant to Water Code section 10724, and authorized the submittal of GSA Formation Information to DWR. Water Code section 10724 provides that the County is presumed to be the GSA for the areas in the Subbasin that are "unmanaged" (not within the management a GSA). SGMA requires the County to give notice to DWR that it intends to undertake sustainable groundwater management and serve as the GSA in the "unmanaged" areas. DWR’s SGMA website portal provides local agencies, GSA’s, and Watermasters the ability to submit, modify, and view the information required by SGMA, and enables the public and interested stakeholders to view submitted information and provide comments, where applicable. No login is required for public access.

On January 7, 2020, the Napa County GSA held its first meeting. The agenda for this first meeting was to elect officers, appoint an executive officer, adopt a 2020 meeting calendar, and approve a resolution authorizing the submittal of a $2.6 million dollar grant application  to the Department of Water Resources (DWR) to support the development of a Groundwater Sustainability Plan for the Napa Valley Subbasin. On February 6, 2020, the Napa County GSA submitted notification  to the Department of Water Resources of their intent to prepare a Groundwater Sustainability Plan for the Napa Valley Subbasin.

The Napa County Groundwater Sustainability Agency (GSA) meets once a month per their adopted calendar. Additional details on upcoming meetings can be found on the GSA’s agendas and minutes webpage and by signing up on the GSA’s email list.

Annual Monitoring and Reporting

SGMA requires annual reporting on groundwater conditions and on any actions taken by Napa County to ensure the sustainable management of Napa Valley groundwater resources. The 2017, 2018 and 2019 Annual Groundwater Reports are available on The reports describe groundwater conditions in the Napa Valley Subbasin and provide an update on the County’s SGMA implementation efforts through water year 2019, as required by SGMA and DWR. Additionally, the 2017 Annual Report includes an Amendment to the 2016 Alternative GSP/Basin Analysis Report, establishing a Northeast Napa Management Area (PDF). The Amendment complements the management actions in the 2016 Alternative GSP/Basin Analysis Report for the Napa Valley Subbasin and enables continued attainment of the SGMA Sustainability Goals for the Napa Valley Subbasin.

Annual reports developed for SGMA purposes are required to be submitted to DWR by April 1 of each year following adoption of a GSP or Alternative GSP (Regulations Section 356.2). The 2020 Annual Report is expected to be available in April 2021.