The drinking water we provide to 2.7 million customers in four Bay Area counties comes from a variety of protected and carefully managed sources. Although the largest percentage of our water comes from snowmelt in the Sierra Nevada, an important part of our water supply comes from rainfall collecting in East Bay and Peninsula reservoirs and filtering into the groundwater aquifer. We serve an ever-changing blend of these different sources to our customers.
By relying on multiple sources of water supply, we help protect our customers from potential disruptions in water supply from emergencies or natural disasters. A diverse mix of water sources also helps us be more resilient to long-term water vulnerabilities such as global climate change, regulatory changes that reduce the amount of water we can use from creeks and rivers, and population growth.