51% – Over half of the District’s water supply is from its own groundwater wells, located in five local basins:
- Chino Basin
- Bunker Hill Basin
- Lytle Creek Basin
- North Riverside Basin
- Rialto-Colton Basin
17% – Additional groundwater is purchased from San Bernardino Valley Municipal Water District through the Base Line Feeder Project. This water also comes from local wells in the Bunker Hill Basin.
18% – The District obtains a portion of its surface water from Lytle Creek in the San Bernardino Mountains. This water is treated through the District’s Oliver P. Roemer Water Filtration Facility.