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State Water Board's Division of Drinking Water Fact Sheet

Reminder About California’s Drinking Water Systems
State-Required Treatment Process Removes Viruses, Including COVID-19
California’s comprehensive and safe drinking water standards require a multi-step treatment process that includes filtration and disinfection. This process removes and kills viruses, including coronaviruses such as COVID-19, as well as bacteria and other pathogens.
The State Water Board’s Division of Drinking Water establishes and enforces drinking water standards that ensure the delivery of pure, safe, and potable water. In addition to health-based water quality standards, treatment facilities must comply with stringent performance measures to ensure treatment processes are continuously operating at peak performance.
The treatment process must destroy at least 99.99% of viruses. The limited number that might pass through the removal process are quickly inactivated in the disinfection process, typically in less than 10 minutes. All treatment facilities for surface water sources in California are required to maintain disinfection facilities sufficient to destroy giardia cysts, which are much more resilient than viruses.
COVID-19 is transmitted person to person, not through water, according to the Centers for Disease Control and Prevention.
Public water systems that utilize groundwater sources maintain protective physical measures, including soil barriers, to ensure that water sources are protected from pathogens, including viruses. In addition, most of these systems use chlorine disinfection to inactivate viruses or bacteria that might find their way into the water.
All public water systems in California are routinely monitored for bacteria to ensure that water delivered to customers is free of disease-causing agents. Other parameters, including temperature, pH, turbidity, chlorine residual, electrical conductivity, lead and copper, corrosion indices and disinfection byproducts, are monitored to alert operators about changing water quality conditions and avert potential problems.
The State Water Board works closely with local water systems to ensure the safety of water that flows through public water systems to residential customers.
Contact your local water agency for more specific information about the drinking water
treatment process. Refer to your water bill for your water provider’s website, phone
number and email contacts.
In addition, California has established a COVID-19 website with prevention tips all
Californians can take to protect themselves from COVID-19 They include staying home,
washing hands with soap and water for 20 seconds, and cleaning and disinfecting
frequently touched objects and surfaces.
Additional Resources
For more information and frequent updates about what California is
doing to prepare for the impacts of Coronavirus (COVID-19), please
visit the Governor’s Office of Emergency Services and the California
Department of Public Health.
United States Environmental Protection Agency: “Americans can continue to use
and drink water from their tap as usual.”
Federal Centers for Disease Control: “The COVID-19 virus has not been detected in
drinking water. Conventional water treatment methods that use filtration and
disinfection, such as those in most municipal drinking water systems, should remove or
inactivate the virus that causes COVID-19.”
(This Fact Sheet was last updated on March 19, 2020)