EPA legal limit
4 ppm
Maximum Contaminant Level
EWG health guideline
No guideline
Science-based, stricter target
Health effects
At EPA-regulated levels (up to 4 mg/L), chloramine is not acutely harmful for the general population. Two groups require specific precautions: kidney dialysis patients (chloramine must be removed from dialysis water — it enters the bloodstream directly through the dialysis membrane) and aquarium fish (chloramine is toxic and does not dissipate like chlorine). Some individuals with eczema or respiratory sensitivity report irritation from bathing in chloramine-treated water. Chloramine produces its own disinfection byproducts — iodoacids and nitrosamines — which are an active area of research and not yet fully regulated.
Where it comes from
Chloramine is intentionally added by water utilities as a disinfectant — it is not an environmental contaminant. Utilities use it primarily to reduce regulated disinfection byproducts (TTHMs and HAA5) that form when free chlorine reacts with organic matter. More than one in five Americans — including residents of Denver, Portland, Boston, Philadelphia, and many other large cities — receive chloramine-treated water. Your utility's Consumer Confidence Report will state which disinfectant is used.
How it's regulated
EPA Maximum Residual Disinfectant Level (MRDL): 4 mg/L (measured as chlorine). This is the enforceable ceiling for chloramine in treated water. Most utilities maintain levels between 1–3 mg/L. Chloramine is regulated as a disinfectant, not a contaminant — its presence is intended and expected in treated water.
How to filter chloramines
Not all filters address chloramines. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.
Frequently asked questions
Does my tap water have chloramine?
More than one in five Americans drink water treated with chloramine. Whether your utility uses it is disclosed in your annual Consumer Confidence Report under the disinfectants section. Enter your ZIP in the WaterHealthCheck tool — if your utility uses chloramine, it will appear in your contaminant profile. Large cities that use chloramine include Denver, Portland, Boston, Philadelphia, and Chicago.
Does chloramine evaporate from tap water?
No. This is the most important practical difference from chlorine. Free chlorine is volatile and off-gasses from water left to sit overnight or when boiled. Chloramine is chemically stable — it does not evaporate at room temperature or at boiling temperature. Leaving water to sit or boiling it does not remove chloramine. A filter is required.
How do I remove chloramine from tap water?
The most effective household method is a catalytic activated carbon block filter — a modified carbon that breaks down chloramine through a catalytic reaction, not just adsorption. Reverse osmosis (NSF 58) also removes chloramine comprehensively. Standard granular activated carbon (GAC) pitchers reduce chloramine partially but less reliably than catalytic carbon. Boiling and letting water sit do not remove chloramine.
Is chloramine safe to drink?
At EPA-regulated levels, chloramine is considered safe for the general population. Kidney dialysis patients require removal of chloramine from treatment water — it is toxic when it enters the bloodstream directly. Aquarium fish are also sensitive and require dedicated dechloramination. For general drinking, chloramine at utility concentrations poses no established acute health risk, though its disinfection byproducts (iodoacids, nitrosamines) are under continuing research.
Why did my utility switch from chlorine to chloramine?
Utilities switch to chloramine primarily to reduce regulated disinfection byproducts — total trihalomethanes (TTHMs) and haloacetic acids (HAA5), which form when free chlorine reacts with organic matter. EPA limits on these byproducts incentivised the switch. Chloramine produces fewer of these regulated compounds but creates different byproducts of its own (iodoacids, nitrosamines) that are increasingly studied. Some utilities switch seasonally — using chlorine in winter and chloramine in summer when organic matter in source water is higher.
Is chloramines in your water?
Enter your ZIP code to see the measured level in your specific utility.