The water that flows from your tap originated from a number of
sources including snowpack, rainfall and underground aquifers.
The majority of the Tri-Valley’s water supply is imported from
outside the region.
During dry years, the water available from the SWP may be
limited, which is why we plan to ensure we can sustain short
cycles of drought by having water stored in underground aquifers
or groundwater basins and surface water reservoirs.
The Livermore Valley
Groundwater Basin is critical for the Tri-Valley in providing
water in normal years and weathering short-term droughts,
providing locally stored water when imported water is unavailable
Zone 7 serves as the sustainable groundwater manager for the
basin — recharging it in normal and wet years and carefully
monitoring it during dry years to ensure it does not become
We also receive water in the form of rainfall runoff stored in
our local reservoir, Lake Del Valle.