Chlorination of drinking water – what is it?

Chlorine in Drinking Water is the process of adding chlorine to the water supply. Drinking water disinfection is most commonly performed using this method. Infectious microorganisms, such as bacteria and viruses, are killed by disinfection. In the process of transporting water from the treatment plant to the consumer’s tap, chlorine ensures the safety of the water.

The United States was once plagued by waterborne diseases such as typhoid fever and dysentery – and they were a leading cause of death. To kill bacteria, viruses, and other microorganisms, cities began disinfecting their drinking water supplies in the early 1900s. Disinfection of drinking water is considered one of the most important advances in public health by the World Health Organization and the Centers for Disease Control and Prevention.

Is it necessary to chlorinate drinking water?

The public water system must be disinfected continuously throughout the treatment process, including the consumer’s tap, with chlorine or other continuous disinfectants.

• Surface water, such as rivers, lakes, and streams, is their source;
• Expose the water to open air or the outside during the treatment process;
• For corrosion control, add treatment chemicals; these chemicals will feed microorganisms and encourage their growth
• Water systems in other communities do not need to be disinfected.

What is the safety of Chlorine in Drinking Water?

Yes, of course. Chlorine levels in drinking water are regulated by the U.S. Environmental Protection Agency (EPA). It is unlikely that long-term health effects will result from the levels of chlorine used in drinking water disinfection.

Chlorine can form disinfection byproducts (DBPs) when it mixes with naturally occurring organic matter in water. Regular, long-term exposure to DBPs can have adverse health effects.

There are several types of DBPs regulated by the EPA. The levels of regulated DBPs in treated water must be tested regularly by all public water systems that disinfect. Water systems are required to reduce DBPs if they exceed EPA limits. The company will notify all of its customers about the DBP levels as part of this action.

Some DBPs are subject to health-based guidance values set by the Minnesota Department of Health. Populations with the highest exposures and/or sensitivity to these values should be protected by these values. Water softener systems in Minnesota can use guidance values as goals, benchmarks, or indicators of potential health concerns without being required to meet health-based guidance values.  Visit Guidance Values and Standards for Contaminants in Drinking Water for more information.

Are there any ways to eliminate taste and/or smell from chlorinated water?

In the beginning of a chlorination process, people often taste or smell chlorine. Tastes and smells will diminish or disappear over time as the system stabilizes. Over time, people usually get used to chlorine in water.

Public water systems strive to keep chlorine levels in their water at a level that effectively disinfects, while minimizing taste and odor.

Can I change the taste and/or smell?

There are a few things you can do if you are bothered by the taste or smell:

• Leave the pitcher of water uncovered in the refrigerator for several hours. By doing this, the chlorine smell will be removed from the water.
• All drinking water should be chilled. The taste and smell of cold water are less problematic. The water will also be less likely to absorb lead and copper from the plumbing if you use cold water.
• Make sure you use a filter. Regular maintenance is required for all water treatment units, even those in your home. In the event that a water treatment unit is not properly maintained over time, its effectiveness will decrease. You can become ill from unmaintained units in some cases.
  • The chlorine taste and smell can be removed by most point-of-use filters (e.g. pitcher filters).
  • The taste and odor of chlorine can be removed with granular activated carbon filters. Compared to point-of-use filters, these are usually more expensive but more effective. You can install them either at the tap/sink or throughout the house.
  • Learn more at Water Treatment.

Is chlorination the only option for disinfection?

In addition to chlorine, there are several other types of disinfectants. There are tradeoffs involved in each. In some cases, chloramines may form fewer regulated DBPs than chlorine, however, depending on the characteristics of the source water, they can form other DBPs and increase corrosion and nitrate formation risks. In the distribution system, chloramines or chlorine must still be added in order to protect the water from DBPs, which can be created by ozone, and it also has no taste. It does not form DBPs in clear water when UV light is used. To protect water from the treatment plant to the tap, chlorine and chloramines must still be added, just as with ozone. Learn more and Contact us