If you notice an unpleasant taste and/or odor to the water in your home, here are some suggestions to assist you in locating the source of the odor:

• If you think the smell is coming from the water, take a container, turn on the tap water, and fill up the container. Then, step away from the sink and smell the water. If there is a noticeable smell, then the source of the smell is the water. If you do not notice a smell, then it is more likely that the smell is coming from the plumbing fixtures. If the smell seems to be coming from the plumbing fixtures, consider flushing the pipes with a mixture of bleach and water. Additionally, remove the aerator, clean with a mixture of bleach and water, and remove any build-up that may be present.
• If the source of the odor is coming from the water, run the hot and cold taps independently and test the water again by smelling it away from the sink. If the smell is from the hot water tap, it is most likely that the smell is coming from the hot water heater. If the smell is from both hot and cold taps, but only from water treated by a softener, then you may have bacteria growing in the water softener.
• If the smell is persistent after running the water and/or you notice the smell in all areas around your home, then the source of the smell is most likely the source water (i.e. the water entering your home). Additionally, if you notice the smell from the water at the front outside hose bib of your home, then the source of the smell is most likely from the source water. If that is the case, contact the Public Works Utilities and Operations Department at 530-757-5686 during regular business hours or contact the non-emergency Police Department number after hours at 530- 747-5400.

To help us investigate taste and smell issues in your tap water, please be prepared to give us the following information:

• What locations in your home have you noticed the taste and/or odor occurring?
• When did you first notice it?
• Is the taste and/or odor in the hot water or cold water or both?
• How would you describe the taste and/or odor of the water?

Chlorine is used as a disinfectant and is added to both the surface water and groundwater at a target residual of 1.0 parts per million. Regulations require minimum chlorine residual to be present in the water at the furthest point of the distribution system. The most common ways to remove chlorine from the water is to boil it, to use a basic carbon filter, or to fill a pitcher of water and allow it to stand until the chlorine odor dissipates.

If you are noticing a strong chlorine smell (i.e. pool-like), please contact the Public Works Utilities and Operations Department during regular business hours at 530-757-5686 or contact the non-emergency Police Department number after hours at 530-747-5400.

Discolored water occurs when mineral deposits that have built up over time in the main lines are dislodged and dissolve back into the water supply. The dissolved minerals can change the color of the drinking water to either brown, black, red, or yellow. This can happen randomly but usually occurs during or after work has been done on the distribution system. This work includes:

• Replacing or repairing a hydrant
• Flushing
• Valve exercising
• Main line repairs or replacement

If you are experiencing discolored water, please contact the Public Works Utilities and Operations Department at 530-757-5686 during regular business hours. To help us investigate the cause of the discolored water, please have the following information prepared:

• In what locations in your home have you noticed the discolored water?
• When was the discolored water first detected?
• What does the water look like? Does it have a color?
• Is the discolored water in the hot water or cold water or both?
• Is the water discolored at all faucets within the home?
• If there are particles in the water, are they large, small, or colored?
• Does the water look milky or contain air bubbles?
• Have you had plumbing work done recently on either hot or cold water lines

Flushing the cold water line to your home and within your home is the best way to clear the lines of any discolored/brown water. To flush the cold water line, follow these steps:

• Start outside of the front of the house at the front hose bib. Open up the front hose bib at a high volume and run it until the water looks clear.
• Once the water looks clear, turn the water off and then flush the cold water lines inside the house. The best way to do this is to open up the cold water tap at a high volume in the bathtub. This will draw out any remaining discolored water in the service line and direct it into only one area of the house. It will also provide enough volume to verify that the water is clear.
• Check the toilet tanks and make sure sediment has not deposited in the tanks. If there is sediment, wipe down the sides and the bottom of the toilet tank and flush until the tank is clear.

If the water does not clear up and you need additional assistance, please contact the Public Works Department during regular business hours at 530-757-5686. After regular business hours contact the non-emergency Police Department number at 530-757-5400.

This is most likely caused by colonies of non-harmful bacteria that thrive in moist environments. To prevent this growth, try to create an environment where the bacteria will not thrive. Keep the area as dry as possible and sterilize the area and the plumbing fixtures as best as possible. This may be done by using bleach, vinegar, and extremely hot water. The site should be cleaned frequently in order to completely remove the bacteria colonies.

When filled in a larger volume white basin or bathtub, water may appear blue. The primary causes of water having a blue tint are the lighting in the area of the basin, or potentially copper corrosion. When light shines on water some colors are absorbed and others are reflected. Typically, the deeper the water is, the more apparent the color. Light bulbs used in the interior of homes produce different types of light. Copper corrosion of interior plumbing can also create a blue-green color in water. This can be caused by a variety of factors, primarily low pH and stray electrical current from the homes electrical system.

The City disinfects its’ groundwater with chlorine at a target residual of 1.0 parts per million. The chlorine may have reacted with stagnant water and/or pipes which can cause yellow water. This sometimes happens when residents are out of town and the water sits in your pipes for a longer than normal period of time.

The City of Davis’ water distribution system is a conjunctive use system, meaning that the City delivers both surface water (water from the Sacramento River) and groundwater (from City wells underground). The City purchases the surface water from the Woodland Davis Clean Water Agency (WDCWA). In 2023, 90% of the water delivered to City customers was surface water. The remaining water delivered was from nine municipal groundwater wells. However, the groundwater used for drinking water primarily comes from four of the City’s deep aquifer wells (the City has other wells that are typically only operated for water quality testing and maintenance).

Surface water is treated at the Regional Water Treatment Facility in Woodland (operated by WDCWA), by traditional surface water treatment techniques, including flash mixing, sand ballasted clarification, ozonation, and granular media filtration. After treatment, the finished water is dosed with chlorine for disinfection and with phosphoric acid to create ortho-phosphate for corrosion control (to minimize corrosion of metal pipes), to achieve a target chlorine residual of 1.0 ppm and 2.0 ppm for orthophosphate. The City disinfects its groundwater with chlorine and the target residual is 1.0 ppm.

Surface water is from the Sacramento River and is treated at the Regional Water Treatment Facility in Woodland. The City supplements the surface water with groundwater primarily from the city’s deep aquifer wells. The water entering your home will be a blend of surface water and groundwater. There is a higher percentage of surface water in the winter (low demand months) compared to the summer (high demand months).

The City targets a range of 45-55 psi in the main lines. Some pressure is lost at the meter as water enters individual properties. Water pressure can also be lost at the backflow if your property has one.

The relative hardness of water will depend on the source. The City of Davis supplies water from two sources: groundwater from City deep aquifer wells and surface water from the Sacramento River. Surface water is naturally softer than local groundwater. In 2015, when the City supplied only groundwater, the average level of water hardness (weighted average) was 306 parts per million (ppm) or 17.9 grains per gallon (gpg). In 2023, the City supplied 90% surface water and the average level of water hardness (weighted average) was 75 ppm or 4.4 gpg. The City takes monthly samples for hardness at five sampling stations around town. For more information about the most recent hardness levels, click here. If you have a water softener, consider bypassing it to determine if the current level of hardness in the tap water is acceptable for your home. If you choose to continue using a water softener, consult with your plumber to choose the appropriate grains setting.

As water travels over the surface of the land or thorough the ground, it dissolves naturally occurring minerals and other elements, and can pick up substances resulting from the presence of animals or from human activity. The Annual Water Quality Report has more information regarding the potential sources of minerals, elements, and substances (known collectively as “constituents”) in your drinking water.

No fluoride is added to the surface water or groundwater; however, trace amounts are naturally occurring in the groundwater.

If you are interested in having your water tested, the link below provides information on Environmental Laboratory Accreditation Program (ELAP) certified laboratories: Environmental Laboratory Accreditation Program (ELAP) | California State Water Resources Control Board

Per-and polyfluoroalkyl substances (PFAS) (also known as “forever chemicals” and perfluorinated compounds) are a large group of human-made chemicals that do not occur naturally in the environment and are resistant to heat, water and oil. PFAS were first used in the 1940’s to create products with stain-, weather- and water resistance. As a result, PFAS are in hundreds of consumer products, such as:

• Non-stick cookware
• Food packaging
• Stain-resistant carpets/furniture
• Waterproof Clothing/Accessories

There are thousands of different PFAS but only some are more widely used and studied which determines which PFAS are regulated. Some types of PFAS, specifically perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are no longer manufactured in the U.S., but these substances are still used in consumer goods produced internationally and imported into the U.S.

Production and usage of PFAS in the U.S. started in the 1940s. Areas where the substances were produced/manufactured have detected PFAS in the air, water and soil. PFAS are resistant to breaking down in the environment, which leads to contamination of soils and groundwater, at sites that produced, manufactured or used PFAS and in waste disposal areas, like landfills where consumer products are thrown away. PFAS can then be introduced into drinking water when products containing PFAS are used or spilled on the ground and percolate down into underground aquifers, or directly into surface waters.

As part of required United States Environmental Protection Agency (US EPA) regulations under the Unregulated Contaminant Monitoring Rule, (UCMR3), the City of Davis sampled for PFAS twice in January and August of 2014 in wells and sampling stations. The results were below the minimum reporting level (the lowest measurable concentration of a contaminant achievable by accredited labs) for PFAS. This sampling predates the Woodland Davis Clean Water Agency (WDCWA) providing surface water (treated Sacramento River water) to the City of Davis beginning in 2016. The City’s water supply, from 2016 onward, is a conjunctive use system of surface water (Sacramento River) and groundwater (wells) sources.

In December 2020, the Sacramento River Watershed Sanitary Survey 2020 Update Report stated that PFAS monitoring in the Sacramento River was conducted in 2019 and all the results were below the detectable limit for PFAS. In 2023, WDCWA started sampling quarterly for 25 types of PFAS from the raw surface water entering the treatment plant and all results were below the minimum reporting level for PFAS.

The 2022 annual water quality report is a state-mandated report that requires that only results above the detectable limit of the analyte/chemical can be included in this report. The last PFOA and PFOS sampling in Davis groundwater was conducted in January and August of 2014 as part of the U.S. EPA Unregulated Contaminant Monitoring Rule (UCMR3) and those results were below the minimum reporting level for all the PFAS chemicals sampled (see list below).

• perfluorooctanoic acid (PFOA)
• perfluorooctane sulfonic acid (PFOS)
• perfluorobutane sulfonic acid (PFBS)
• perfluorohexane sulfonic acid (PFHxS)
• perfluorohepatonic acid (PFHpA)
• perfluorononanoic acid (PFNA)

The City of Davis started sampling for PFAS within the distribution system in 2024 (as part of the U.S. EPA Unregulated Contaminant Monitoring Rule, UCMR5). The groundwater (active wells) and the treated surface water will be sampled for 29 May 2024 PFAS substances two times throughout 2024. WDCWA continues to sample the surface water supply from the Sacramento River for 25 types of PFAS and all samples continue to be below the minimum reporting level. All sampling (UCMR5 and Sacramento River via WDCWA) will be reported on the 2024 water quality report if the minimum reporting level of PFAS is exceeded.

On April 10, 2024, EPA announced the final National Primary Drinking Water Regulation (NPDWR) for six PFAS. PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS using a Hazard Index as a Maximum Contaminant Level (MCL) to account for the combined and co-occurring levels of these PFAS in drinking water.

 For more information about the PFAS regulations, visit the EPA website on PFAS.

The City will post all detected results above the minimum reporting levels in the annual Water Quality Report. If PFAS sampling results are above the minimum reporting level, residents will be sent notification that includes the concentration of PFAS detected and the associated health concerns for that specific substance. May 2024 Depending on the concentration of the PFAS detected, the City will determine if the source should be removed from producing water and/or consider possible treatment for PFAS at that source.

The use of water filters is a personal decision for each individual based on their specific health concerns; the utilization of a filter is a consumer choice, and the City of Davis does not endorse any specific water treatment device. However, caution is advised when considering the use of a water filter specifically for the removal of a contaminant (such as PFAS) that has not been detected in the water. Currently, no at-home treatment devices can remove all PFAS, as the existing analytical methods (lab testing) cannot demonstrate complete removal of PFAS. Should you purchase a home treatment device or household filter, we do recommend that it be independently certified for the intended purpose (to reduce PFOA/PFOS) by American National Standards Institute (ANSI) and/or the National Sanitation Foundation International (NSF). The packaging of the device or product website should have in the description a statement, or mark, or emblem of NSF/ANSI 53 or NSF/ANSI 58 certification for PFAS reduction. Below is a link to the US EPA fact sheet on reducing PFAS in your drinking water with a home filter.

EPA Water Filter Fact Sheet