Water Quality

Providing safe water to its 24 retail member agencies and their customers is the Water Authority’s top priority. Rigorous treatment processes combined with continuous water quality monitoring, ensure that the Water Authority is delivering high-quality water to its member agencies 24 hours a day, seven days a week.


Water quality overview

All drinking water provided by the Water Authority complies with high state and federal standards to ensure its quality. In fact, the multi-step treatment processes required by the state removes and kills bacteria and viruses, including coronaviruses such as COVID-19. In addition to health-based water quality standards, facilities that serve the San Diego metropolitan area comply with strict performance measures to ensure treatment processes are continuously operating at peak performance.

Because of these efforts, the region’s drinking water remains safe even during the pandemic, and the U.S. EPA recommends that Americans continue to drink tap water.

Drinking water supplied by the Water Authority to its member agencies comes from three primary sources: the Claude "Bud" Lewis Carlsbad Desalination Plant, the Robert A. Skinner Water Treatment Plant in Riverside County -- owned and operated by the Metropolitan Water District of Southern California -- and the Twin Oaks Valley Water Treatment Plant north of San Marcos.

To ensure the delivery of safe and reliable water supplies, water quality is monitored continuously and testing for nearly 400 constituents takes place throughout the year. Constituents are tested at the frequency mandated by federal or state regulations.

Here are the 2019 annual water quality reports from each facility that provides water to the Water Authority. State and federal regulations require that all water agencies make public an annual Consumer Confidence Report that includes information about water quality testing performed each year on water provided to consumers.

In addition to the Water Authority, other agencies that own and operate treatment plants within the county include:

Whether the water is treated by MWD, the Water Authority, or a local agency, all treated water served in San Diego County meets or exceeds rigorous state and federal water quality standards.

Additional Information:

Learn more about fluoridation.

Learn more about lead testing.

Learn more about the water treatment process

Learn more about the Twin Oaks Valley Water Treatment Plant

Other Resources:

Metropolitan Water District: water quality

California State Water Resources Control Board - Division of Drinking Water