Groundwater is a critical part of the water system in Lake and Mendocino Counties. For many rural households, farms, and small water systems, groundwater accessed through wells is the primary source of water for drinking, irrigation, and everyday use.

We invite you to explore the tools below to learn more about groundwater conditions in your area, including water levels, quality, and long-term trends across California.

Explore Groundwater Data and Tools

• California Department of Water Resources (DWR) Water Data Library
  Groundwater level data, well information, and historical records
  https://wdl.water.ca.gov/

• DWR SGMA Portal
  Basin information, groundwater sustainability plans (where applicable), and agency contacts
  https://sgma.water.ca.gov/portal/

• USGS Water Data for California
  Groundwater monitoring and hydrologic data across the state
  https://waterdata.usgs.gov/ca/nwis/

• California Water Boards GAMA Program
  Groundwater quality data, including contaminants and water chemistry
  https://www.waterboards.ca.gov/gama/