What Is Chloramine in Water?
The EPA says chloramines are drinking water disinfectants, most commonly formed when ammonia is added to chlorine, that provide longer-lasting disinfection as water moves through pipes to consumers. It says water utilities have used them since the 1930s and that more than one in five Americans uses drinking water treated with chloramines. CDC says utilities may switch to chloramine because chlorine gets used up quickly in water, chloramine keeps killing germs in water pipes longer, and it makes fewer disinfection byproducts than chlorine.
Federal rules at 40 CFR 141.65 set the maximum residual disinfectant level for chloramines at 4.0 mg/L, measured as chlorine, the same level as for chlorine, and CDC says chlorine or chloramine levels up to 4 mg/L are considered safe in drinking water.
Some uses need it removed. CDC says dialysis centers must treat water to remove all chemical disinfectants, including chlorine and chloramine, before it is used for dialysis, and that people doing dialysis at home should check their machine's instructions or contact the manufacturer about treating water. A 2009 EPA fact sheet says chlorine and monochloramine can be harmful to fish because they enter the bloodstream directly through the gills.
It is harder to get rid of than chlorine. CDC says chlorine can be removed by letting water sit out for a few days, but chloramine cannot be removed that way, and a 2009 EPA fact sheet says monochloramine can be more difficult to remove from drinking water than chlorine and that boiling water does not remove it.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceThe EPA says chloramines are drinking water disinfectants most commonly formed when ammonia is added to chlorine, providing longer-lasting disinfection as water moves through pipes. US EPA ↗
- Government sourceThe EPA says water utilities have used chloramines since the 1930s, and more than one in five Americans uses drinking water treated with chloramines. US EPA ↗
- Government sourceCDC says utilities may switch to chloramine because it keeps killing germs in pipes longer than chlorine and makes fewer disinfection byproducts. CDC ↗
- Regulatory filingFederal drinking water rules at 40 CFR 141.65 set the maximum residual disinfectant level for chloramines at 4.0 mg/L as chlorine, the same as for chlorine. US EPA, 40 CFR 141.65 (eCFR) ↗
- Government sourceCDC says chlorine or chloramine levels up to 4 milligrams per liter are considered safe in drinking water. CDC ↗
- Government sourceCDC says dialysis centers must remove all chemical disinfectants, including chloramine, from water before dialysis, and home dialysis patients should check machine instructions. CDC ↗
- Government sourceA 2009 EPA fact sheet says chlorine and monochloramine can be harmful to fish because they enter the bloodstream directly through the gills. US EPA ↗
- Government sourceCDC says chlorine can be removed from water by letting it sit out for a few days, but chloramine cannot be removed this way. CDC ↗
- Government sourceA 2009 EPA fact sheet says monochloramine can be more difficult to remove from drinking water than chlorine, and boiling water does not remove it. US EPA ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.