Each year, communities across America take time to recognize an important but unseen part of our water supply: groundwater. During National Groundwater Awareness Week, March 8–14, we focus on protecting this valuable resource and highlight local efforts to keep groundwater safe and reliable.
In Santa Clara County, local groundwater basins hold more than double the amount of water stored in all 10 of our surface reservoirs. Groundwater provides about half of the water used in Santa Clara County, and nearly all the water used in South County. Groundwater is also the county’s primary reserve in times of drought.
Since water retailers and private well owners pump more groundwater than nature can replenish, it’s vital to manage it responsibly. Valley Water was created more than 95 years ago to address serious groundwater challenges.
Back then, people in the county pumped groundwater faster than it could naturally replenish. This led to unreliable water supplies and significant land subsidence.
Before halting subsidence in 1970, parts of San José sank as much as 13 feet. This sinking led to infrastructure damage, heightened flood risk and concerns about seawater intrusion from San Francisco Bay.
Those lessons continue to guide how Valley Water manages our groundwater today.
Valley Water replenishes groundwater basins using surface water in percolation ponds and streams that is captured in local reservoirs and brought from outside the county. We also reduce groundwater demand by providing alternative supplies, like treated and recycled water, along with ongoing conservation programs. Today, groundwater levels are healthy throughout the county.
Groundwater quality is equally important. Contaminants like industrial spills, leaking fuel tanks and fertilizers can harm groundwater supplies. That’s why Valley Water operates a groundwater monitoring program. Our staff checks water quality throughout the county and evaluates data from local water suppliers.
These efforts allow us to assess the overall quality of groundwater in the region and identify potential threats, enabling us to address them appropriately.
National Groundwater Awareness Week began in 1999 to promote responsible use and management of groundwater nationwide. It reminds private well owners to regularly check and maintain their water systems.
The National Groundwater Association recommends that well owners test their water and have their systems inspected annually by certified contractors. This ensures that wells work properly and provide safe drinking water.
As part of its commitment to groundwater protection and public health, Valley Water offers water quality testing for eligible Santa Clara County residents served by domestic wells. Testing is available for most domestic wells in South County. Residents can learn more or check eligibility by calling the Groundwater Hotline at 408.630.2300.
Whether through Valley Water’s program or a certified laboratory, all domestic well owners are encouraged to test their water annually, especially if they notice changes in taste, odor, or appearance.
Groundwater remains one of Santa Clara County’s most valuable resources. By managing it responsibly and staying informed, we can protect this hidden resource for generations to come.
Director John L. Varela represents District 1 on the Valley Water board of directors.
