Zone 7's surface water is comprised mostly of State Water Project water which originates in the Feather River in the Sierra Nevada mountains and is imported through the Bay-Delta. This water supply is augmented by a small amount of other imported water supplies as well as runoff from local rainfall.
These surface supplies, some of which are stored in Del Valle Reservoir, are purified at Zone 7's treatment plants. When needed, Zone 7 also pumps water from the groundwater basin.
Zone 7 blends these sources for delivery to its water retailers, and stores surplus surface supplies in local and offsite groundwater banks for use during peak-demand periods and for reliability during droughts. The actual source of the water from your tap can vary depending on the time of year, rainfall levels and where you live in the Valley.
To view various reports and planning documents, click here.
Water Supply Evaluation
Zone 7 continuously strives to provide a reliable and high-quality water supply through the build-out of the Valley. The Agency's Water Supply Evaluation [WSE] assesses the risks of a water supply shortage and is being used to help formulate a strategy for addressing projected shortages.
For a copy of the 2011 Water Supply Evaluation, click here.
The 2011 WSE evaluated a diverse set of water supply options for meeting the Valley’s water supply needs. One of these options is a regional desalination facility being developed in partnership with the Bay Area’s largest water supply agencies (EBMUD, SFPUC, SCVWD, and CCWD). For more information about the Bay Area Regional Desalination Project (BARDP), click here.
HOW THE WATER FLOWS
Once imported water arrives in the Livermore-Amador Valley, most is treated by Zone 7 for delivery to water retailers serving Pleasanton, Livermore, Dublin and Dougherty Valley, who in turn deliver it to you. Another portion of imported untreated water is used by Valley agricultural customers, and some is recharged into the groundwater basin for use when needed. Another portion of our Delta-conveyed water is sent to offsite groundwater-banking programs.