Groundwater

Recent:  On December 17, 2019, the Napa County Board of Supervisors adopted a resolution affirming the County's intent to manage groundwater in the Napa Valley Subbasin and to form the Napa County Groundwater Sustainability Agency (GSA) for the Napa Valley Subbasin. The Sustainable Groundwater Management Act (SGMA) requires governments with high and medium priority basins to bring groundwater basins into balanced levels of pumping and recharge. Under SGMA, these basins should reach sustainability within 20 years of implementing their sustainability plans. Napa County has until January 31, 2022 to submit a Groundwater Sustainability Plan (GSP) for the Napa Valley Subbasin.

Groundwater Stakeholder Survey

Napa County and the Watershed Information and Conservation Council (WICC) have developed an online survey to better understand the interests of groundwater stakeholders. The survey results will guide groundwater outreach efforts to advance Napa County's Groundwater Sustainability Program.

CLICK HERE to take the survey. Your input is very important and will help improve the various ways groundwater information and education programs are offered to our community.

The Importance of Groundwater

Groundwater is a vital source of water supply in Napa County. Residents, businesses and agriculturists rely on groundwater, as do fish, wildlife and natural habitats. It is essential to:

  • Preserve the quality and availability of all local and imported water supplies
  • Sustain groundwater supplies to meet future needs and availability during drought conditions
  • Anticipate and avoid potential environmental effects due to the overuse of groundwater
  • Anticipate and take steps to avoid potential losses in long-term groundwater availability and quality.

Everyone in Napa County has a stake in protecting the County's groundwater resources. Without sustainable groundwater resources, the character of the County would be significantly different in terms of its economy, communities, and ecology.

"Well Owners Guide, A guide for private well owners in Napa County (PDF) " is a new guide intended to make private well ownership a little easier, by alerting well owners of potential sources of contamination and the need for periodic water quality testing, by introducing the basics of proper well construction, destruction and maintenance, and informs well owners of their responsibilities in Napa County.

Annual Monitoring and Reporting

Napa County regularly monitors groundwater levels. Each year an annual report on groundwater conditions and trends is provided to the public. On March 19th, Napa County Public Works provided the Groundwater Sustainability: Annual Report - Water Year 2018 (PDF) to the Board of Supervisors. The 2018 Annual Report summarizes activities implemented to improve the understanding of groundwater resource conditions and actions taken to ensure continued groundwater sustainability in the Napa Valley Subbasin.

For more information about groundwater in your local area, visit the Watershed Information and Conservation Council (WICC) website. The WICC receives on-going groundwater updates at their bi-monthly meetings. Check the WICC event calendar for upcoming meetings.

Do-It-Yourself (DIY) Groundwater Level Monitoring

Napa County is offering assessments, training and tools to residents to help them monitor the level of groundwater in their well. This program allows residents to learn how water depth in their well changes over the course of the year and helps them to better understand how the groundwater reservoir beneath their land responds to winter recharge and use over the dry months. Measurements are best taken in the spring and fall over multiple years to see trends in recharge. You can learn more about the DIY Groundwater Monitoring Program by viewing this short video and downloading the program flier (PDF).

Alternative Groundwater Sustainability Plan (GSP)

Basin Analysis Report for the Napa Valley Groundwater Subbasin

Final documents of the Napa Valley Groundwater Sustainability - Basin Analysis Report for the Napa Valley Subbasin (Alternative GSP) are available below. The Final Alternative GSP was submitted to the Department of Water Resources (DWR) on December 16, 2016.

On October 11, 2019, Napa County provided a response to the Department of Water Resources’ (DWR) preliminary evaluation of the County’s alternative Groundwater Sustainability Plan (GSP) for the Napa Valley Subbasin. DWR’s initial recommendation is to not approve the County’s Alternative GSP. Napa County prepared the response to address DWR's questions and other requested clarifications related to the alternative GSP.

DWR notified Napa County on November 13, 2019 that it had 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.

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 Tuesday, 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). 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.

The Alternative GSP is available below and a hard-copy of is available at the Napa County Flood Control and Water Conservation District Office, 804 First St. Napa, (707) 259-8600.