You can find details about groundwater in your local area by visiting the Watershed Information and Conservation Council (WICC) website.

New: Special Study Examines Localized Northeast Napa Groundwater Trends - On Tuesday, October 24th at 11:00am the Napa County Board of Supervisors will receive a presentation and report on a Special Study of groundwater level trends in a small portion of the Napa Valley Groundwater Subbasin located northeast of the City of Napa and west of the Milliken, Sarco, Tulocay (MST) creek drainages. Links to the presentation and Special Study report are available HERE.

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" 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.

Refer back to this webpage often to learn what Napa County is doing to comply with the SGMA and ensure the sustainability of local groundwater resources.

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 is a new program to allows residents to learn how water depth in their well changes over the course of the year and help 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).