Chlorine vs. Chloramines

In the United States, the goal of the Safe Water Drinking Act was to provide safe drinking water for citizens. The Environmental Protection Agency maintains the standards associated with that goal. The EPA standards require treatment of tap water at any faucet to kill bacteria and mitigate harmful health contaminants. Tap water should contain a chlorine concentration of at least 0.2 parts per million; to improve the effectiveness of added chlorine, municipal water supplies increasingly add chloramine, a combination of chlorine and ammonia that is more stable than pure chlorine. The chlorine concentration of the water that comes out of your tap will be depend on how far you are from the water plant, how long it takes the water to travel from the water plant to your house, the air temperature, due to its influence on evaporation, and how much chlorine is initially added. 

Chlorine can combine with certain organics (that may or may not be present in your water) forming trihalomethanes, a family of carcinogens. President Obama’s Cancer Research Panel released in 2010 urged all Americans to use a point of use drinking water system to better protect their families from water-borne diseases and cancer-causing agents in our tap water. Simply put, we want the chlorine in the water to kill bacteria, but we want to remove it right before we drink.

Water utilities often refer to chloramine as monochloramine. Trihalomethanes (THMs) are disinfection byproducts that are formed when organic matter in the water combines with chlorine. THMs are also formed with chloramine disinfection but at a lower concentration, about 1/3 less than chlorine. Filtration for chloramine is very expensive compared to filtration for chlorine and is considered to be a less effective disinfectant than chlorine. The World Health Organization (WHO) says that “monochloramine is about 2,000 and 100,000 times less effective than free chlorine for the inactivation of E. Coli and rotaviruses, respectively.” Here are some interesting comparisons between chlorine and chloramine:

  • Chloramine does not dissipate easily compared to chlorine, leading to or aggravating respiratory problems because its harmful ammonia remains in the air longer. A study from the Catholic University of Louvain in Belgium showed an increase in asthma due to exposure from chloramine in indoor swimming pool areas.
  • Chloramine stays in the water distribution system longer than chlorine. Tropical fish hobbyists discover, often at great cost, the harmful effects on their aquatic environments from chloramine byproducts that, unlike chlorine, cannot be boiled out or dissipated over time
  • Chloramine is more difficult to remove than chlorine.
  • Some disinfection byproducts of chloramine are even more toxic than those of chlorine, such as iodoacids.

More empirical studies document the detrimental effect of chlorine on human, plant, and animal health simply because more municipalities have used chlorine longer rather than chloramine at their facilities; chloramine studies will likely increase over time and studies already suggest that chloramine may actually be worse than chlorine. Federal law requires all municipal water providers to disclose the composition of your water along with the treatment and disinfection methods.

If you are not happy with or concerned about your water supplier’s disinfection method and its possible undesired effect on your health, Water4 offers a selection of water filtration systems right where your municipal water enters your home’s plumbing and at your tap. There are many models to choose, including backflush and drainfree systems and options to mitigate fluoride and the effects of hard water.