The Chino Basin Groundwater Aquifer is a major water supply source for the communities in the Santa Ana Watershed. In IEUA’s service area alone, Chino Basin accounts for up to 40% of the drinking water supply. As a result of development, natural groundwater recharge that would occur during rain events has diminished. It is estimated that today, approximately 30,000 AF per year–or the equivalent of half of IEUA’s imported water supplies from the State Water Project–are lost to stormwater runoff. To counteract this, IEUA is working with its partners in the Chino Basin Groundwater Recharge programs and local agencies to capture and store as much stormwater as possible. This helps protect local water supplies and the environment by decreasing polluted runoff and reducing the risk of flooding.

Learn more on our Stormwater Management page.