While chlorine is used to disinfect water and make it safe to drink, exposure to high levels of chlorine or its byproducts can cause respiratory issues, skin irritation, and exacerbate conditions like asthma.

Chlorine in Tap Water

Chlorine is a chemical commonly added to tap water to disinfect it and make it safe for drinking. It's an essential step in water treatment because it kills harmful bacteria, viruses, and other microorganisms that can make people sick. Chlorine has been used for this purpose for over a century because it's highly effective at destroying these harmful pathogens.

Disinfection Byproducts (DBPs)

When chlorine is added to water, it reacts with naturally occurring organic matter, like leaves or algae in the water, and forms compounds called disinfection byproducts (DBPs). Some common DBPs include trihalomethanes (THMs) and haloacetic acids (HAAs). While chlorine itself is necessary for water safety, DBPs can pose some concerns.

Health Concerns

Long-term exposure to high levels of certain DBPs in drinking water has been associated with some health risks. These risks include an increased likelihood of developing certain types of cancer, such as bladder and colorectal cancer. However, it's essential to note that these risks are generally associated with prolonged exposure to very high levels of DBPs, often much higher than what is typically found in treated tap water.

Regulation and Monitoring

To ensure the safety of tap water, regulatory agencies like the Environmental Protection Agency (EPA) in the United States have established strict guidelines for the allowable levels of DBPs in drinking water. Water treatment plants are required to monitor and control DBP levels to keep them within safe limits.

Reducing DBP Exposure

There are ways to reduce DBP exposure from tap water:

- Using water filters: Some water filters, such as activated carbon filters, can help reduce the levels of DBPs in drinking water.

- Allowing water to sit: Some DBPs are volatile and can dissipate if you let your tap water sit uncovered for a while before using it for drinking or cooking.

- Switching to alternative disinfection methods: Some water treatment plants are exploring alternative disinfection methods that produce fewer DBPs, such as ozone or ultraviolet (UV) treatment.


Chlorine and the formation of DBPs are essential aspects of ensuring the safety of tap water by disinfecting it. While there are some health concerns associated with DBPs at very high levels, the regulatory guidelines in place aim to keep DBP levels in tap water within safe limits to protect public health. If you have specific concerns about the water quality in your area, you can request water quality reports from your local water utility or consider using water filtration systems to further improve the taste and odor of your tap water.