How We Operate
Providing safe, clean water for a healthy life, environment and economy
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How We Operate
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About Valley Water

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Who we are 

Founded in 1929, Valley Water provides safe, clean water; flood protection; and stewardship of streams.


Water sources 

Imported water: Snowmelt from the Sierra Nevada travels hundreds of miles through rivers, into the Sacramento-San Joaquin Delta and then to Santa Clara County treatment plants or groundwater basins, where it accounts for half the water we use here. Contracts with the state and the federal government determine how much “imported” Sierra Nevada water we receive each year.

Groundwater: Santa Clara County’s largest reservoir is beneath our feet. Our groundwater basins hold more water than our ten surface reservoirs combined. As the groundwater management agency for Santa Clara County, Valley Water actively manages our groundwater basins, replenishing them with local and imported water through our percolation ponds and stream beds.

If water is pumped out of the ground faster than it is replaced, the result can be the sinking of the land elevation. Called subsidence, this can have costly effects on infrastructure and water quality. Maintaining our groundwater levels is critical for ensuring a reliable water supply, storing water for use during droughts and shortages, and preventing subsidence.

Purified water: Purifying recycled water provides a drought-proof, locally controlled water supply that will help us meet the needs of Silicon Valley now and into the future. The Silicon Valley Advanced Water Purification Center, the largest purification facility in Northern California, purifies recycled water to near-distilled quality using proven technology—microfiltration, reverse osmosis and ultraviolet disinfection.

The result is 8 million gallons a day of highly purified water that meets California’s strict drinking water quality standards.

Conservation: Water conservation is essential in providing a reliable water supply to current and future generations. Our long-term water supply plan calls for annual water savings of more than 32 billion gallons per year by 2030. Since the late 1980s, the population of Santa Clara County has increased by roughly 25 percent, yet water use over that time has remained relatively flat.


Water supply 

Dams/Reservoirs: Santa Clara County’s ten reservoirs hold enough water for 340,000 families of fi­ve for one year. They catch storm runoff that otherwise would flow into San Francisco Bay.

Water treatment plants: Valley Water operates three water treatment plants that clean and disinfect imported water and water from four of our local reservoirs. The three water treatment plants can produce as much as 220 million gallons of drinking water a day.

Water quality laboratory: Ensuring all water supplies are safe and clean is our highest priority. We continuously test our water quality in Santa Clara County to do so. Valley Water's state-of-the-art water quality lab performed nearly 175,000 tests in 2014.

We test water produced from each of our three water treatment plants, our Silicon Valley Advanced Water Purifi­cation Center, our reservoirs and groundwater basins. Our treated water consistently meets or is better than all applicable water quality regulatory standards. These standards are becoming increasingly stringent as technology is developed to detect contaminants at very minute levels.


Watersheds: ­Flood protection and stream stewardship 

Flood protection projects: Valley Water manages about 294 miles of creeks in Santa Clara County. To provide flood protection to the county’s growing community, we build projects such as the Guadalupe River and Lower Silver Creek flood protection projects and manage our flood protection infrastructure. Our projects have protected nearly 100,000 parcels, and we have 18 projects to protect 25,000 more over the next five years.

Stream Maintenance: Each year, crews can be seen in our creeks working to remove sediment, stabilize banks and remove vegetation. This work is critical for maintaining our waterways and preparing for the rainy season. Controlling sediment in streams ensures flood protection projects provide maximum flood protection.

Sandbags: You can download a map listing sandbag sites by visiting the sandbag distribution location page.

Healthy creeks and ecosystems: Approximately 1/3 of the more than 800 miles of creeks and rivers in Santa Clara County are owned by the Valley Water.

The health of a creek reflects the conditions throughout the watershed, not just those along its banks. Valley Water's environmental work protects and restores habitats and encourages the return of endangered species such as the red-legged frog, steelhead trout and salt marsh harvest mouse.

Valley Water also partners with cities and the county to provide open space and recreational opportunities at many of its ten reservoirs and along creeks throughout the county. Since 2000, public access to more than 70 miles of new creekside trails has been made available in the county.