Chloramine in tap water

What is chloramine, and why do utilities use it?

Chloramine is formed when chlorine is combined with ammonia. It is used as a secondary disinfectant—added after primary treatment to maintain a residual that prevents bacterial regrowth as water travels through distribution pipes to your tap.

Utilities switched to chloramine for a specific regulatory reason: the EPA's Disinfectants and Disinfection Byproducts Rule limits total trihalomethanes (TTHMs) and haloacetic acids (HAA5), which are the byproducts that form when chlorine reacts with organic matter in water. Chloramine produces fewer of these regulated byproducts than free chlorine, making it easier for large utilities to stay within EPA limits.

The tradeoff is that chloramine is harder for consumers to remove at the point of use than chlorine.

Does my tap water have chloramine?

Not all utilities use chloramine. Roughly two-thirds of US utilities still use free chlorine as their primary residual disinfectant. Whether your utility uses chloramine is disclosed in your annual Consumer Confidence Report (CCR)—the annual water quality summary your utility is required to send you, or which you can find on your utility's website—it will be listed under the disinfectant section.

Large utilities that have historically used chloramine include New York City, Los Angeles, Chicago, Philadelphia, and San Francisco—though utility practices can change. Always verify against your current CCR.

The fastest way to check: enter your ZIP code in the WaterHealthCheck tool. If your utility uses chloramine, it will appear in your contaminant profile.

Does chloramine evaporate from tap water?

No. This is the most important practical difference between chloramine and chlorine.

Free chlorine is volatile—it off-gasses from water at room temperature over several hours, and more rapidly when water is boiled or agitated. Many people are aware that leaving tap water in an open container overnight reduces its chlorine content. This is true for chlorine.

Chloramine does not behave this way. It is chemically more stable and does not evaporate from water at room temperature or at boiling temperature. Boiling chloramine-treated water does not remove the chloramine—it concentrates it slightly as water volume reduces through evaporation.

This matters for:

Health effects of chloramine in drinking water

Chloramine at the concentrations used for water disinfection (typically 1–4 mg/L, within the EPA's 4 mg/L limit) is not acutely toxic. The EPA considers it safe for most people at regulated levels. However, several populations have documented concerns:

Inhalation: what the research shows

The research on inhaled chloramine is primarily from occupational settings. Lifeguards and pool workers breathe trichloramine above chlorinated pools for hours at a time, and studies have found statistically significant associations with upper respiratory symptoms, including hoarseness, sinusitis, and asthma-like symptoms at these exposure levels (Thickett et al., 2002; Jacobs et al., 2007). Whether daily shower exposure at typical household concentrations produces similar effects is not established by direct research.

What is reasonable: people with existing asthma, eczema, or respiratory sensitivity in hot, poorly ventilated showers may experience irritation. Improving bathroom ventilation and showering at lower temperatures reduces exposure regardless of filtration.

For households in chloramine utilities who want to reduce shower exposure—particularly those with asthma, eczema, or young children—a shower filter or bath filter with catalytic carbon media is the targeted solution. Standard shower filters using KDF or basic carbon have limited effectiveness against chloramine; look specifically for catalytic carbon. A Drawn Health consultation can assess whether shower filtration is appropriate alongside or instead of a drinking water solution for your household.

How to remove chloramine from tap water

The filter type matters significantly. Chloramine is harder to remove than chlorine because of its chemical stability.

What works: catalytic carbon block (best option)

Catalytic activated carbon is a modified form of activated carbon with a higher surface reactivity. It is specifically effective at breaking down chloramine through a catalytic reaction, not just adsorption. Look for filters labelled as catalytic carbon or coconut shell catalytic carbon.

NSF certification to look for: NSF/ANSI 42 (aesthetic effects, chlorine/chloramine reduction) or NSF/ANSI 53 (health effects). Check that the specific product's Performance Data Sheet lists chloramine reduction—not all NSF 42 certified filters cover chloramine.

Formats: under-sink carbon block filters, countertop units, whole-house systems with catalytic carbon media.

What works: reverse osmosis (comprehensive)

Reverse osmosis removes chloramine along with PFAS, nitrate, arsenic, lead, and most other dissolved contaminants. If your water report shows chloramine plus other contaminants of concern—PFAS, lead, TTHMs—RO is the most efficient single solution. NSF certification: NSF/ANSI 58.

What partially works: standard granular activated carbon (GAC)

Standard GAC filters—including most pitcher filters—do reduce chloramine to some degree, but less reliably and less completely than catalytic carbon. A fresh GAC filter will remove some chloramine; as the filter ages, performance drops more quickly for chloramine than for chlorine.

The practical implication: if you use a standard pitcher filter in a chloramine utility, replace filters more frequently than the manufacturer recommends for chlorine-only utilities.

What does not work: boiling, letting water sit, aeration

As noted above, chloramine does not evaporate. None of these approaches reliably removes chloramine.

Filter comparison for chloramine removal

Chloramine and the Kangen Water® ionizer—why this matters if you're considering one

If you've been researching water ionizers, chloramine in your tap water is a detail that matters before you buy.

Most water ionizers—including the Kangen K8—come with a standard activated carbon pre-filter (Enagic®'s FC1) that is effective for free chlorine. But chloramine is more chemically stable than chlorine and requires a different filter media: catalytic activated carbon, not standard carbon. Running a Kangen machine on a chloramine utility with the wrong pre-filter means the chloramine passes through the electrolysis chamber, affecting the ioniser's performance and the quality of the water it produces.

Enagic makes two pre-filter options that specifically address chloramine:

How to know which filter configuration your water needs

If your utility uses chloramine—visible in your WaterHealthCheck report—and you're considering a Kangen Water® system, you need either the Black filter or the Enametix in the pre-filter stack. Which one depends on the rest of your water profile: whether PFAS, fluoride, or lead are also present, your water hardness, and whether you're on municipal or well water.