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Certified Laboratories


Testing your well water

The thousands of wells that draw water from the county’s groundwater basins generally produce high quality drinking water. Valley Water’s hundreds of monitoring wells provide data about regional groundwater quality; however, every property and well has unique features and conditions. Valley Water’s Guide for the Private Well Owner has information on recommended testing for domestic wells, but in general 

  • Valley Water recommends that domestic well owners test their well water annually for coliform bacteria, nitrate, and electrical conductivity.
  • Changes in the color, odor, or taste of your well water should also prompt water quality testing.

The laboratories listed below are located in Santa Clara County and are certified to perform drinking water tests by the State Water Resources Control Board Division of Drinking Water. Please contact the laboratory of interest for more information on services offered. For a complete list of certified laboratories, visit the Division of Drinking Water, Environmental Laboratory Accreditation Program webpage.

Laboratory Laboratory Certification
Renewal Date
CM Analytical, Inc.
6700 Brem Lane, #10
Gilroy, CA 95020
(408) 848-3619
Santa Clara County Public Health Lab (Bacterial Testing Only)
2220 Moorpark Avenue, 2nd Floor
San Jose, CA 95128
(408) 885-4272

Torrent Laboratory, Inc
483 Sinclair Frontage Road
Milpitas, CA 95035
(408) 263-5258


Source: State Water Resources Control Board Division of Drinking Water (DDW) website and communication with laboratory staff (updated April 2024). The information provided is subject to change and may not be current. If you have questions about services offered by a specific laboratory, please contact the laboratory directly. For information on state certification for a laboratory, please call the DDW at (510) 620-3155.