Water Quality

Water Quality in Hillsborough

Hillsborough's water is noted for its clarity, taste, and purity. This high-quality water supply meets all federal and state criteria for watershed protection, disinfection treatment, bacteriological quality, and operational standards at its source in the Hetch Hetchy Reservoir. As a result, the Environmental Protection Agency (EPA) and California Department of Health Services (CDHS) granted the Hetch Hetchy water source a filtration exemption. This exemption is contingent upon the Hetch Hetchy source continuing to meet all filtration avoidance criteria.

Both the San Francisco Public Utilities Commission (SFPUC) and the Hillsborough Department of Public Works (DPW) work hard to assure that the water delivered to your home is of the highest quality possible.

Lady drinking water

Drinking water may be reasonably expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the EPA’s Safe Drinking Water Hotline at 800-426-4791.


Hillsborough water is treated with chloramine, a disinfectant the SFPUC adds to water for public health protection. It is a combination of chlorine and ammonia that is currently considered the best technology for controlling the formation of certain regulated organic disinfection byproducts. Chloraminated water is safe for people and animals to drink, and for all other general uses. However, as with chlorine, chloramine will need to be removed for fish and amphibian use and for people or businesses requiring highly treated water.

Unlike chlorine, chloramine cannot be removed from water by boiling or by letting an open container of water stand to dissipate chlorine. It can only be neutralized or removed with specific treatment methods.

For customers with aquariums or koi ponds: Local Bay Area pet stores stock a number of products that effectively treat the water for both fresh and salt water fish. For more information, you can refer to links posted on the SFPUC website.

For homeowners with plumbing repairs or remodeling projects: Use chloramine-resistant plumbing materials that are widely available at local Bay Area home improvement and plumbing supply retail stores.

For customers who undergo dialysis treatment: The CDHS inspects all hemodialysis clinics, including those that use SFPUC water, to make sure that their equipment and procedures meet all applicable health and safety standards.


Fluoride ions are present naturally in water supplies throughout California. When fluoride is present in drinking water at prescribed levels, it has been shown to promote oral health by preventing tooth decay. However, the amount of natural fluoride in water supplies is usually not enough to provide any oral health benefits.

Water fluoridation is the addition of small amounts of fluoride to a water supply to achieve a fluoride level that helps prevent tooth decay. For more information on water fluoridation, please visit the Centers for Disease Control and Prevention website.

Water Quality Reports

Each year, the Town of Hillsborough publishes the results of its water quality testing operations in a consumer confidence report. 

View the Town’s Water Quality Reports:

2022 Water Quality Report (PDF)

2021 Water Quality Report (PDF)

2020 Water Quality Report (PDF)

2019 Water Quality Report (PDF)

2018 Water Quality Report (PDF)

You can also look at reports by the SFPUC in the Water Quality section of the SFPUC website.

Water Quality Tips

Read the following tips to learn how to maintain good water quality in your home:

  • Flush the faucets if you have been away from your home for several days.
  • Flush the faucets for your guests who will be staying in seldom-used rooms.
  • Drink and cook with water from the cold water faucet only.
  • Flush your water heater annually. Sediments will accumulate in the bottom of the water heater tank over time and can cause bad tastes and odors.
  • Insist that any new plumbing fixtures installed in your home meet state standards for lead content. If you have any questions regarding a specific fixture, consult with the Hillsborough Building Department for guidance.
  • Install anti-siphon fittings on all hose faucets. These inexpensive devices help to prevent accidental siphoning of chemicals used in the yard or garage from getting into your home's water supply.
Water faucet