Napa County announced on Mar. 11 that it is joining the National Ground Water Association and communities nationwide in recognizing National Groundwater Awareness Week, which runs from March 8 to 14. The week aims to highlight the importance of managing and protecting groundwater resources.
Groundwater is a key resource for Napa County, supporting its wine industry, providing drinking water, and sustaining local landscapes and ecosystems. Amber Manfree, Chair of the Napa County Board of Supervisors, said, “Reliable groundwater is essential to Napa County’s agricultural economy, rural communities, and healthy waterways. Groundwater Awareness Week highlights the work underway to sustainably manage the Napa Valley Subbasin so there is enough water to support our community in warm, dry years and during drought. By reducing water use and increasing groundwater recharge, we can protect this shared resource for future generations.”
Recent rainfall has helped replenish groundwater supplies in the region. However, officials say careful management remains necessary for long-term sustainability. The Napa Valley Subbasin covers about 46,600 acres from Highways 221 and 12 north toward Calistoga and is classified as a high-priority subbasin by state authorities. In 2025, approximately 16,600 acre-feet of water was pumped from the subbasin—enough for around 33,000 households annually.
Following California’s Sustainable Groundwater Management Act passed in 2014, Napa County developed a Groundwater Sustainability Plan for the subbasin that received state approval in January 2023. Since then, the county’s Groundwater Sustainability Agency has implemented workplans focused on protecting groundwater resources while supporting agriculture and natural habitats.
The agency is conducting studies at six monitoring sites across the basin to better understand how surface water and groundwater interact throughout the year. These efforts include biological surveys, habitat assessments, flow measurements, groundwater monitoring, and hydrologic modeling aimed at supporting healthy ecosystems.
Additionally, a voluntary Water Certification Partnership Pilot Program is being developed with local organizations to encourage conservation practices among vineyards and wineries while maintaining data privacy standards. If successful, this program could expand further within the subbasin.
Management of these efforts falls under the county’s Groundwater Sustainability Agency with guidance from a five-member Technical Advisory Group of scientific experts. Public participation is encouraged through meetings whose agendas are available online along with resources for well owners.
