How do I know if my tap water has chloramines?

Check your annual Consumer Confidence Report (CCR). Your water utility is required to mail or post it each year, and it will list the disinfectant your system uses. You can also call your utility directly and ask. If they say "monochloramine," your water has chloramines.

Does Brita filter chloramines?

Standard Brita pitchers use activated carbon, which is much less effective at removing chloramines than free chlorine. Chloramine bonds are harder to break. For meaningful chloramine reduction, look for filters that specifically use catalytic carbon and carry NSF/ANSI 42 certification for chloramine reduction. A standard pitcher filter won't do the job reliably.

Are chloramines in drinking water safe?

The EPA sets a Maximum Residual Disinfectant Level of 4.0 mg/L for chloramines, and the CDC notes that at levels used in drinking water, the disinfectant itself poses minimal health risk for most people. That said, chloramines are toxic to fish and must be removed for dialysis patients. Some unregulated byproducts that chloramines can form are still under active research.

Do shower filters remove chloramines?

Most shower filters use calcium sulfite, which works on free chlorine but is much less effective on chloramines. If you specifically want chloramine reduction in the shower, look for filters using KDF-55 media or vitamin C (ascorbic acid) and check for NSF/ANSI 177 certification that covers chloramine. Don't assume a shower filter removes chloramines just because it removes chlorine.

Why did my city switch from chlorine to chloramines?

Chloramines produce fewer regulated disinfection byproducts, specifically trihalomethanes (THMs) and haloacetic acids (HAAs), than free chlorine. When the EPA tightened limits on those byproducts, many utilities switched to chloramines to stay within legal limits. Chloramines also last longer in distribution pipes, which helps maintain disinfection in large water systems.

Chloramines in Tap Water: Why Your City Switched and What It Means

Health disclaimer: This page provides general information about chloramines in drinking water. It is not medical advice. If you have a specific health condition, consult your doctor or healthcare provider before making decisions about water treatment. Dialysis patients and fish owners should take special precautions (see the sections below).

Hundreds of US cities have quietly changed how they disinfect tap water over the past two decades. If your water smells a little different than it used to, or if you’ve recently moved to a new city and noticed a change in your water’s taste, chloramines may be the reason.

The switch from free chlorine to chloramines wasn’t random. It was driven by federal regulations. But it came with tradeoffs that most utilities don’t advertise.

What Chloramines Are and Why Utilities Use Them

Chloramines form when a water utility adds ammonia to water that’s already been treated with chlorine. The result is monochloramine, usually just called chloramine. It’s a less reactive disinfectant than free chlorine, which sounds like a downside, but that’s exactly what makes it useful for large distribution systems. Chloramine doesn’t break down as fast, so it stays active as water travels through miles of pipes to reach your tap.

The bigger reason utilities switched: chloramine produces fewer regulated disinfection byproducts. When free chlorine reacts with organic matter naturally present in source water, it forms trihalomethanes (THMs) and haloacetic acids (HAAs). Both are regulated by the EPA because of links to cancer and other health effects with long-term exposure. Chloramine forms much lower levels of these specific byproducts.

When the EPA tightened THM and HAA limits in the late 1990s and early 2000s, utilities in large cities faced a choice: install expensive new treatment technology or switch disinfectants. Many chose chloramines.

EPA Limits and What They Mean

The EPA sets a Maximum Residual Disinfectant Level (MRDL) for chloramines at 4.0 mg/L, measured as chlorine equivalent. This is the maximum amount allowed to remain in the water when it reaches your tap. Your utility is required to stay below that limit.

The CDC notes that at the concentrations used in drinking water treatment, chloramine poses minimal health risk for most people. You can read the CDC’s statement directly at cdc.gov. The EPA’s chloramine drinking water regulations are at epa.gov/dwreginfo/chloramines-drinking-water.

“Minimal risk for most people” is an important phrase. There are specific groups for whom chloramine is a real hazard. More on that below.

The Tradeoffs: What Chloramines Do Differently

Chloramine is not a straight upgrade from free chlorine. It trades one set of problems for a different set.

On the positive side: fewer regulated THMs and HAAs at the tap, and longer-lasting disinfection in pipes. That matters in large cities with extensive distribution systems.

On the negative side: chloramine forms different unregulated byproducts, including certain nitrosamines and iodoacids. These aren’t yet subject to EPA limits, but they’re under active research. The science isn’t settled on their long-term health effects. Chloramine is also harder to remove than free chlorine, which affects filtering choices at home.

It’s also more corrosive to some plumbing materials. That point deserves its own section.

The Lead Pipe Connection

This is the part most utilities don’t tell you about in their annual water quality reports.

A 2007 study published in Environmental Health Perspectives looked at what happened in Washington, D.C. after the city switched from free chlorine to chloramines. The study found an association between chloramine use and higher blood lead levels in children in Washington, D.C. The researchers proposed that chloramine may be more corrosive to lead pipes than free chlorine, releasing more lead into water as a result. You can read the full study at pmc.ncbi.nlm.nih.gov/articles/PMC1817676.

To be clear about what this study shows: it identified an association in one city’s data. It does not prove that chloramines cause lead poisoning. The proposed corrosion mechanism is plausible and has been studied further, but the evidence comes from a specific context. Washington, D.C. had a high concentration of older lead service lines at the time.

What this means practically: if you’re on a water system that uses chloramines and your home has old plumbing, lead service lines, or pre-1986 solder, the combination may be higher risk than chloramine or old pipes alone. Testing your water for lead is a reasonable step. Our lead contamination page covers how to test and what to do if you find it.

Who Needs to Pay Special Attention

Fish owners. Chloramines are toxic to fish even at the low levels used in drinking water. Standard dechlorination products that say they “remove chlorine” often don’t address chloramine. If you have a fish tank and your utility uses chloramines, you need a dechlorinator that specifically states it neutralizes chloramine, not just free chlorine. Check the product label carefully.

Dialysis patients. Dialysis machines pass large volumes of water directly into the bloodstream in effect, so disinfectants that are safe to drink can be harmful in that context. Dialysis centers are required to treat water to remove chloramines before use. If you receive home dialysis, your care team should be handling water treatment as part of your setup. Confirm it with your dialysis provider.

For both groups, this isn’t a minor inconvenience. It’s a genuine safety issue.

How to Remove Chloramines from Drinking Water

Chloramine is harder to remove than free chlorine, so your filter choice matters.

Catalytic carbon filters are the most practical option for most households. Standard activated carbon, the kind in most pitcher filters, has limited effectiveness against chloramine because chloramine bonds are more stable than free chlorine. Catalytic carbon has a different surface structure that’s specifically effective at breaking those bonds. Look for filters labeled “catalytic carbon” or certified to NSF/ANSI 42 for chloramine reduction.

Reverse osmosis systems remove chloramines effectively. RO pushes water through a semi-permeable membrane that blocks most dissolved contaminants including disinfectants. If you’re already considering RO for other reasons, it will handle chloramines too. See our treatment page for more on how RO works.

Vitamin C (ascorbic acid) neutralizes chloramines on contact. It’s commonly used in whole-house shower systems and for filling pools or hot tubs. Some shower filters use ascorbic acid cartridges specifically for this purpose.

What doesn’t work well: Standard activated carbon alone. Boiling. Free chlorine will off-gas if you leave water out overnight or boil it, but chloramine doesn’t evaporate the same way. Boiling water won’t meaningfully reduce chloramine levels, and may actually concentrate some other dissolved solids.

Shower Filters: A Specific Note

Most shower filters sold online and in stores use calcium sulfite as the primary filter media. Calcium sulfite works on free chlorine. It’s much less effective on chloramines.

If your utility uses chloramines and you want to reduce them in the shower, you need a filter that specifically addresses chloramine. KDF-55 media and vitamin C (ascorbic acid) cartridges are the options with meaningful effectiveness. Ideally, look for NSF/ANSI 177 certification that explicitly covers chloramine reduction, not just general chlorine removal.

Don’t buy a shower filter that says “removes chlorine” and assume it covers chloramine. Those are different claims.

How to Find Out If Your City Uses Chloramines

Call your utility and ask. That’s the fastest way. They’re required to disclose their disinfection method.

You can also read your Consumer Confidence Report (CCR). Every community water system is required to send customers an annual water quality report. It lists what disinfectant your utility uses. If it says “chloramine” or “monochloramine,” you have your answer. Your testing page has more on reading water quality reports and understanding what the numbers mean.

If you find your water uses chloramines and you want to reduce your exposure, a catalytic carbon filter at your kitchen tap is the most practical starting point. Make sure the product is specifically rated for chloramine reduction, not just general chlorine. That one distinction determines whether the filter actually works.

For byproducts like THMs that chloramine helps reduce but doesn’t eliminate entirely, see our page on disinfection byproducts.

Health disclaimer: WaterAnswer.com provides general information only. This page is not medical or clinical advice. Dialysis patients should consult their care team about water treatment requirements. If you have concerns about specific health conditions related to water quality, speak with your healthcare provider.