Disinfection with Chloramine

Chloramination is the process of adding chloramine to drinking water to disinfect it and kill germs. Chloramination is sometimes used as an alternative to chlorination. Chloramines are a group of chemical compounds that contain chlorine and ammonia. The particular type of chloramine used in drinking water disinfection is called monochloramine. Monochloramine is mixed into water in levels that kill germs but are still safe to drink ¹.

Monochloramine is a different chemical from dichloramine and trichloramine, which are chloramines formed by other complex chemical reactions. Dichloramine and trichloramine are chloramine compounds sometimes found in and around indoor swimming pools, which cause skin, eye, and respiratory problems ³. These chemicals are not usually linked to drinking water.

Chloramine has been used as a drinking water disinfectant in the U.S. in places like Cleveland, Ohio, Springfield, Illinois, and Lansing, Michigan since 1929. In 1998, an EPA survey estimated 68 million Americans were drinking water disinfected with chloramine ¹. Several major U.S. cities such as Philadelphia, San Francisco, Tampa Bay, and Washington, D.C. use chloramine to disinfect drinking water ⁴. Chloramine is recognized as a safe disinfectant and a good alternative to chlorine ⁵.

Safe drinking water

Current studies indicate that using or drinking water with small amounts of chloramine does not cause harmful health effects and provides protection against waterborne disease outbreaks ⁶. These studies reported no observed health effects from drinking water with chloramine levels of less than 50 mg/L in drinking water ⁷. A normal level for drinking water disinfection can range from 1.0 to 4.0 mg/L ⁸.

Your health

Your water company monitors water quality regularly to provide you with safe drinking water. Some people are more sensitive than others to chemicals and changes in their environment. Individuals who have health concerns should seek medical advice from their healthcare provider before contacting their local health department.

Contact your local health department for more information.

Dialysis patients

During dialysis, large amounts of water are used to clean waste products out of a patient’s blood. Dialysis centers must treat the water to remove all chemical disinfectants, including chlorine and chloramine, before the water can be used for dialysis. Home dialysis users should consult the machine manufacturer for instructions on how to properly treat their water before use.

Dichloramine and Trichloramine

Skin, eye, and respiratory problems have been linked to dichloramine and trichloramine exposure in relation to indoor swimming pools and hot tubs. However, dichloramine and trichloramine are typically not an issue in treated drinking water, which uses monochloramine, because utilities carefully monitor the water quality ³.

Chloramine levels up to 4 milligrams per liter (mg/L) or 4 parts per million (ppm) are considered safe in drinking water. At these levels, no harmful health effects are likely to occur ⁵.

The U.S. Environmental Protection Agency (EPA) allows drinking water treatment plants to use chloramine and chlorine to disinfect drinking water. Research shows that chloramine and chlorine both have benefits and drawbacks.

Chlorine is a highly effective method of disinfection. However, it produces small amounts of chemicals (called "disinfection by-products") while in the pipes if the source water has higher levels of dirt or germs that may react with chlorine ¹. These disinfection by-products can cause illness after drinking them for a long time.

Chlorine is also used up quickly in water systems. Sometimes there is not enough chlorine left to kill germs in the water by the time it reaches the end of the pipes. Chloramine can last longer in the water pipes and produces fewer disinfection by-products ¹. To meet the EPA standards intended to reduce disinfection byproducts, some water utilities are switching to chloramine.

If you notice any change in the taste or smell of your water, it will be that the water treated with chloramine has less of a "chlorine" taste and smell than water treated with chlorine ¹.

Chloramine can change the chemical properties of the water, which can affect lead and copper pipes. Lead and copper levels are strictly regulated in drinking water ^{9, 10}. Your water utility is required to provide high-quality drinking water that complies with the Safe Drinking Water Act [PDF - 4 pages] ¹¹. The EPA provides a manual [PDF - 462 pages] ¹² for water companies switching to chloramine to minimize lead and copper levels.

If you are concerned about lead or copper levels in your household water, call EPA’s Safe Drinking Water Hotline at 800-426-4791 for testing information.

Chlorine and chloramine are toxic to fish, other aquatic animals, reptiles and amphibians ¹. Unlike humans and other household pets, these types of animals absorb water directly into the blood stream ¹. Don’t keep these animals in water that contains these disinfectants. Unlike chlorine, chloramine cannot be removed by letting water sit out for a few days. However, products are available at aquarium supply stores that can remove chloramine ¹. Ask your local pet store about methods of removing disinfectants from water for these pets.

The small amount of chloramine added to water will not affect other pets (such as mammals and birds) and can be used regularly for watering and bathing animals ¹.

Plants are not harmed by water treated with chloramine ¹.