Why Does Tap Water Sometimes Taste Like Chlorine, and How Can You Reduce It?

The chlorine taste sometimes detected in tap water comes from the disinfectant added during treatment to eliminate bacteria, viruses and other microorganisms.

Why is chlorine added to drinking water?

Water treatment plants use chlorine (usually as sodium hypochlorite or chlorine gas) because it is an effective, inexpensive and easy-to-dose disinfectant. Its main function is to destroy pathogens that could cause gastrointestinal illnesses and ensure that the water reaches consumers free of microbiological risks.

How do we perceive the taste of chlorine?

Chlorine dissolved in water reacts with naturally occurring organic compounds and can form byproducts such as chloramines, which are responsible for the characteristic odor and taste. Our perception of the taste depends on the concentration of these compounds and each person's individual sensitivity.

Factors that influence the intensity of the taste

• Amount of chlorine added: this varies depending on the quality of the source water and local regulations.
• Contact time: the longer water remains in the pipes, the greater the formation of chloramines can be.
• Temperature: warm water tends to release more volatile compounds, which intensifies the odor and taste.
• Presence of organic matter: a higher amount of precursors results in more flavorful byproducts.

How to reduce the chlorine taste at home

1. Let the water sit uncovered for 15-30 minutes: chlorine is volatile and partially dissipates into the air.
2. Use an activated carbon filter: carbon adsorbs chlorine and its byproducts, improving taste and odor.
3. Boil the water for 5 minutes: heat speeds up the evaporation of chlorine, although it can also concentrate certain minerals if too much water evaporates.
4. Add a slice of lemon, lime, or a few mint leaves: citric acids can mask the taste and, in some cases, react with the chlorine, reducing its perception.
5. Use filter pitchers with ion-exchange technology or reverse osmosis membranes: these systems remove chlorine more thoroughly, although their cost and maintenance are higher.

It's important to remember that chlorine serves an essential sanitary safety function. If you decide to reduce its presence in the water you drink, it's advisable to ensure the water remains potable through other means (for example, certified filters) and to avoid storing it for extended periods without disinfection.