SANTA CLARA COUNTY, Calif. (KRON) — The next time you drive by a reservoir, you might want to take a good long look because they are disappearing fast as the latest drought tightens its grip on the Bay Area and beyond.

Lexington and other reservoirs around the Santa Clara Valley are mostly dependent on runoff from rainfall. 

But rainfall was well below normal last winter, so there wasn’t all that much runoff. Lexington is about 28% full right now. 

Together, the 10 Santa Clara valley reservoirs are just 16% full, well below their 20-year historical average of 26%. 

Reservoirs account for about half the valley’s annual needs. The rest comes from groundwater reserves and they are still in pretty good shape, says Valley Water’s Matt Kellar.

Looming large in a prolonged drought is the fact that Anderson Reservoir in Morgan Hill, larger than all other reservoirs combined, is virtually empty, at just 3% of capacity. 

It was drained and will stay that way for 10 years while the dam, built on an earthquake fault, undergoes a seismic retrofit. 

On top of that, allocations of state and federal water have also been cutback which means Valley Water will soon be shopping for more, says Kellar.

Valley Water’s board has thus far decided against mandatory rationing this summer while calling instead for a goal of 25% voluntary conservation while doubling incentives for replacing lawns with drought tolerant landscaping.

Bottom line, a lot is riding on what happens — if and when winter rains return.