Hawaii draws on volcanic basalt aquifers, including basal freshwater lenses floating on seawater.
We're building out Hawaii coverage from the USGS national groundwater databases — the National Water Information System and the National Ground-Water Monitoring Network — which catalog groundwater sites, well depths, and water levels nationwide. Check back soon.
State groundwater agency: Hawaii Commission on Water Resource Management
Meanwhile, you can find water well drillers in Hawaii or see all covered states.