Drinking Water Quality

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Detailed information about the City's water quality is available in the 2018 Water Quality Report. Previous year reports are also available for review.

The City of Vacaville’s water system is a safe and reliable drinking water supply and meets all state and federal water quality regulations prior to being provided to water customers.

Water quality standards are established by the U.S. Environmental Protection Agency (US EPA) and the California State Water Resources Control Board. The City extensively tests its water wells, treatment plants, and throughout the distribution system to verify water quality and ensure the water served to customers meets drinking water standards.

All drinking water, including bottled water, may reasonably be 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 US EPA’s Safe Drinking Water Hotline at (800) 426-4791.

Who do I call if I have concerns about my water quality?

The Utilities Department at (707) 469-6400 will take a report from you and notify the water plant. You will be informed of the results of your inquiry. The list below of common water quality concerns may answer some of your questions.

Common Water Quality Concerns

Taste and Odor

It is very difficult to separate taste from odor because the two human senses are so closely related. Water can pick up tastes and odors from treatment additives, new pipes, low usage in the water system, or natural substances in the source water. Tastes and odors in treated water are not harmful, but the City does take steps to try and eliminate them.

Chlorine Smell

The most common complaint is a chlorine smell to the water. Chlorine is added to ensure that the water that makes it to your home or business is free of bacteria. California allows the City to have up to 4 parts per million chlorine residual in the drinking water. The City maintains the level around 0.8 parts per million with a maximum of 1.4 parts per million to reduce taste and odor issues. Further reduction of taste and odor can be achieved by installing point-of-use carbon filters or by allowing water to sit in a pitcher in the refrigerator for about an hour before use.

“Rotten Egg” Smell

Also known as "sulfur odor," the "rotten egg" smell in water is caused by the reaction of sulfates and microorganisms in unchlorinated water. Because the City’s water is chlorinated, the cause of most sulfur odor issues is debris in the sink p-trap below the faucet where the odor is observed. This can be resolved by flushing water down the p-trap to clear the odor-causing debris. If you still suspect the water supply to be the source of the smell, check to see whether both cold and hot water contain the odor. Run the hot water to check for odor. Then move to another faucet and run the cold water. If the hot water alone has odor, then the odor is likely coming from the water heater. This may require a call to a plumber to resolve. If the cold water has an odor, then the source is in the cold water. Before calling the City to report a cold water rotten egg smell, check that the smell is not gas trapped in the p-traps of your sewer drain system being pushed up as water flows to the sewer.

Cloudy Water

Cloudy water can be a result of dissolved air in the water, which is a common and harmless condition. To verify this, place the cloudy water in a glass and observe for 2 minutes. If it clears from the bottom up, then you only have dissolved air in the water. (You may be left with bubbles on the side of the glass and a small surface layer of bubbles.) If the cloudy water persists, or if you are noticing particles or unusual tastes or odors, please call the Utilities Department and a water operator will come check your water.


Discoloration is usually rust from aging pipes. It is not harmful, but is aesthetically displeasing. Home plumbing, especially in older homes, can also cause discoloration of the water. Disturbances in the water line can also cause discoloration of the water, including improper hydrant use, new pipe installation, or local maintenance shutdowns.

Hard Water

Hardness of the water varies from one part of the city to another. It is the main cause of white scaling and spotting on glassware. The higher the concentration of hardness-causing minerals in your water, the more white scale you will notice on faucets and other fixtures. Wiping down faucets and shower doors immediately after use is the best way to prevent hardness buildup.