Did you know our county’s largest reservoir is right beneath our feet? Santa Clara County’s aquifers hold more water than all 10 reservoirs combined, more than twice as much. Through layers of permeable rock and soil, water filters naturally to underground basins. Groundwater Awareness Week is celebrated in March every year and serves as an opportunity to highlight this nearly invisible, but essential resource.
As the groundwater management agency for the county, the Santa Clara Valley Water District works to protect and replenish groundwater supplies. Nearly half of all water used in our county is pumped from the ground through wells. During years with minimal rainfall, we rely more heavily on groundwater to meet our county’s demands. However, pumping too much water can have serious consequences such as subsidence, or sinking of the land. Subsidence is very dangerous and costly to the community, threatening critical infrastructure such as pipe systems, bridges and roads, to name a few.
That’s why it’s so important to protect our groundwater resources. We replenish this water source by releasing water from our reservoirs to creeks and through our system of percolation ponds countywide. Using less water also helps protect groundwater reserves. During the recent drought, Santa Clara County residents did an amazing job reducing water use, and have continued to show that conservation is a California way of life. Since 2015, residents have consistently reduced water use by 20 percent or more, compared to usage levels in 2013. Because of these efforts and our work to replenish groundwater, our groundwater basins have recovered to pre-drought levels.
One important thing to remember about groundwater is that what we do on the land above affects our water supply underground. Whether you are a well owner, or are served by one of the region’s local water retailers, you can help protect the quality of our groundwater. Reduce household chemical use and properly dispose of motor oil and unwanted or unused chemicals and medications. Limit the amount of pesticides and fertilizers used in your yard. You can do this by planting low water-use plants which require less maintenance and minimize the need to use chemicals. Get a list of tips on protecting and conserving groundwater.
Industrial spills, leaking underground fuel tanks, septic systems, agricultural operations, storm runoff and other sources can threaten our groundwater quality. The water district works with land use and regulatory agencies to minimize the risk of groundwater contamination, and permits the construction and destruction of wells to help protect drinking water.
We work with our local water suppliers and individual well owners to evaluate groundwater quality. Local water suppliers, such as cities or water companies, regularly test wells to ensure compliance with state and federal drinking standards. The water district offers basic water quality testing for eligible private domestic wells and rebates for well owners with exposure to high nitrate levels. We encourage private well owners to have well water tested annually by a certified lab to protect your health; and more frequently if you notice a change in color, odor or taste. For more information on testing, maintenance and protection, review the district’s guide for private well owners.
During Groundwater Awareness Week, we hope you learn something new about this hidden and lesser known source of water, and can help keep it safe. Whether it’s reducing household and outdoor chemical use, or helping us prepare for the next drought by ramping up water conservation, our actions can have a resounding impact. Sign-up for our newsletter for more information on water quality, groundwater management, conservation and more.