Taste & Odor

Probable Cause: Naturally occurring algae in reservoirs that produce compounds such as Geosmin and Methylisoborneol (MIB). These tastes and odors are most likely to occur in the fall when the algae start to die off and they release the compounds.

Is the water safe? Yes. While Geosmin and MIB can be detected by humans at very low levels, they are not harmful and occur naturally in some vegetables.

What is the BOPU doing to prevent this taste/odor?

BOPU Staff prevent the conditions that create these taste/odors in the water in Cheyenne’s reservoirs by transferring colder water from reservoirs at higher elevations to local reservoirs.

BOPU Staff also monitor and control algae growth in Cheyenne’s reservoirs throughout the summer. Each week, staff visit reservoirs to monitor water quality and algae growth. If algae growth begins to bloom, staff can prune the bloom by using a peroxide based algaecide. The algaecide the BOPU uses works quickly and breaks down into byproducts (hydrogen peroxide and oxygen) that quickly dissipate from water. 

During the fall, when the water is more likely to contain the taste/odor compounds, the water treatment plant adds an additional treatment step that uses activated carbon to remove taste/odor compounds from the water. 

Probable Cause: Chlorine. The BOPU uses chlorine as a disinfectant during water treatment to eradicate harmful bacteria and microbes.

Is the water safe? Yes. The “bleachy” smell, while many find it unpleasant, is necessary to protect the water from harmful bacteria or microbes.

To remove the taste/odor:

1. Use a filter with activated carbon to remove the chlorine.
2. Fill a pitcher with water and let is sit. The chlorine will dissipate from the water. Also, pouring water between two pitchers speeds this process.
3. It may sound counter-intuitive, but a high chlorine smell often indicates that the chlorine is being used up, possibly because the water has been in the pipes in the building longer than normal. Running cold water from the faucet can help “freshen” the water by pulling fresh water from water mains.

What is the BOPU doing to prevent this taste/odor?

The US Environmental Protection Agency (EPA) requires that drinking water from public systems maintain enough chlorine in the water to be detectable throughout the system but not greater than 4 milligrams per liter (mg/L). BOPU water treatment plant operators and laboratory staff monitor water quality 24 hours a day, every day. They strive to maintain between 0.2 mg/L to 1.0 mg/L of chlorine in Cheyenne’s water that is in the pipes being delivered to customers.

Probable Cause: Lead, iron or copper. Water that sits in metallic pipes and fixtures (such as faucets) used in buildings for long periods of time can dissolve metals such as lead, iron or copper from the pipes or fixtures.

Is the water safe? The BOPU monitors Cheyenne’s water to make sure the water is safe. However, we can’t control the types of pipes used in buildings. If you are concerned about lead, iron or copper from the pipes in the building, the U.S. Environmental Protection Agency (EPA) has suggestions on how to prevent exposure. Visit epa.gov to learn more.

What is the BOPU doing to prevent lead, iron and copper in Cheyenne’s water? Water treatment operators adjust the acidity of Cheyenne’s water and blend the water with ground water to add alkalinity to the water. Water with a pH above 7.0 is not acidic and is less likely to dissolve metals from pipes or fixtures. Water treatment operators maintain Cheyenne’s water with pH’s between 7.4 and 7.6. This helps keep the water from dissolving metals from pipes. Operators also add alkalinity to water by blending treated water with water from wells. Water from wells will have more minerals that provide alkalinity to the water. Alkalinity provides a buffer that prevents water from changing pH as it is delivered to customers.