Chloramine is chlorine bonded with ammonia – longer-lasting but harder to filter. Chlorine evaporates and gets caught by basic carbon filters. Over 1 in 5 U.S. water systems switched to chloramine in the past decade to meet disinfection rules, which is why many carbon filters suddenly stopped working.
If your water filter worked fine for years and then suddenly your tap water started tasting like a swimming pool, the problem probably isn't your filter. It's chloramine.
According to the EPA's Safe Drinking Water Act requirements, utilities must maintain a disinfectant residual in distribution pipes to prevent bacterial regrowth. Chlorine has been the default for over a century. But when utilities started failing EPA limits on disinfection byproducts (trihalomethanes and haloacetic acids), many switched to chloramine – a compound that forms fewer regulated byproducts but behaves completely differently in your home.
Here's what changed and why it matters.
| Dimension | Chlorine | Chloramine | |-----------|----------|------------| | Smell/Taste | Strong pool smell, dissipates in 24 hours | Faint or no smell, persists for days | | Standard Carbon Filter | Removed easily (activated carbon) | Breaks through GAC; needs catalytic carbon | | Byproducts Formed | Trihalomethanes (THMs), haloacetic acids (HAAs) | Lower THMs/HAAs, but forms NDMA (not federally regulated) | | Cost to Utility | Higher (requires more frequent dosing) | Lower (longer-lasting, single dose at plant) | | Removal Method | Evaporation, boiling, or standard carbon | Catalytic carbon, reverse osmosis, or long contact time | | Health Risk (EPA View) | Safe at required levels (≤4 mg/L) | Safe at required levels (≤4 mg/L) but concerns for dialysis, fish tanks |
The table shows why utilities love chloramine and homeowners hate it. Chloramine costs less and meets federal disinfection byproduct limits more easily than chlorine. But it also slips right through the pitcher filter that used to handle chlorine just fine.
Standard granular activated carbon (GAC) filters remove chlorine through a fast surface reaction. Chlorine molecules hit the carbon and break down within seconds. Easy.
Chloramine is a more stable molecule. It doesn't break down on contact with standard carbon – it needs catalytic carbon, which is carbon treated to speed up the breakdown reaction. According to the American Water Works Association's 2023 disinfection report, chloramine requires 3-5 times longer contact time with carbon media compared to chlorine, or a different filter media entirely.
If your utility switched from chlorine to chloramine and didn't tell you (many don't – they're only required to notify in the annual water quality report buried on their website), your existing filter didn't change. The water chemistry did.
Translation: your Brita or PUR pitcher, which was certified to remove chlorine taste and odor, probably isn't certified for chloramine. Check the NSF 42 certification on the box – if it only says "chlorine reduction," it won't touch chloramine.
Honestly, this catches most people off guard. You assume your filter broke. The filter's fine. Your water utility just switched disinfectants and nobody sent you a letter.
Over 113 million Americans now drink chloraminated water, according to EPA's 2025 Public Water System Survey. Major switches in the past decade include:
The pattern: older pipe systems with THM violations switched first. Newer systems are staying with chlorine unless they hit regulatory limits.
Not sure which disinfectant your city uses? Check your water quality by ZIP code – our tool pulls EPA data that includes disinfectant type.
The EPA sets maximum residual disinfectant levels at 4 mg/L for both chlorine and chloramine. Both are considered safe for drinking at those levels.
But the byproduct story is more complicated. Chlorine reacts with natural organic matter in water to form trihalomethanes (THMs) and haloacetic acids (HAAs), both of which are linked to bladder cancer risk at high exposure levels. The EPA regulates these tightly: 80 µg/L for total THMs, 60 µg/L for HAA5.
Chloramine forms lower levels of THMs and HAAs – that's why utilities switch. But it forms a different byproduct: N-nitrosodimethylamine (NDMA), a probable carcinogen. The EPA has not set a federal limit for NDMA in drinking water, though California set a notification level of 10 ng/L in 2023.
According to the Centers for Disease Control's 2024 guidance on drinking water disinfection, the cancer risk from either disinfectant at EPA-allowed levels is far lower than the risk of not disinfecting water at all. Waterborne disease outbreaks (cholera, E. coli, Legionella) killed thousands annually before disinfection became standard in the early 1900s.
My take: the disinfection tradeoff is worth it. Chloramine's NDMA risk is probably lower than chlorine's THM risk, but we don't have a federal limit on NDMA yet so it's hard to say for sure. The research here is early – most long-term epidemiology studies tracked chlorine, not chloramine.
The bigger concern is for specific populations: - Dialysis patients must remove chloramine from water used in dialysis machines (it damages red blood cells if it enters the bloodstream directly) - Aquarium owners must remove chloramine before adding tap water to fish tanks (it's toxic to fish and beneficial bacteria) - Some people with chemical sensitivities report skin irritation from bathing in chloraminated water (anecdotal, not well-studied)
If you fall into one of those groups, removal matters. For everyone else, it's mostly about taste and whether you want to filter it out.
Removing Chlorine: - Let it sit uncovered for 24 hours (it off-gasses) - Boil for 1 minute (speeds up evaporation) - Run through any activated carbon filter (Brita, PUR, fridge filter, faucet-mount) - Reverse osmosis system
Removing Chloramine: - Catalytic carbon filter (look for NSF 42 certification that specifically lists "chloramine reduction") - Reverse osmosis system - UV light + catalytic carbon (some whole-home systems use this combo) - Long contact time with standard carbon – 10+ minutes, which is impractical for most home filters
We recommend catalytic carbon for chloramine. It's the most practical option. Standard carbon eventually works if the contact time is long enough, but pitcher filters don't give you 10 minutes of contact – water passes through in under 30 seconds.
Popular filters certified for chloramine removal include: - Aquasana AQ-5200 under-sink filter (catalytic carbon, NSF 42 for chloramine) - Big Berkey with Black Berkey filters (claims chloramine reduction, though NSF certification is unclear) - ZeroWater 10-Cup Pitcher (ion exchange, not carbon – removes chloramine but also all minerals, which affects taste)
For a full breakdown of which filters handle both chloramine and PFAS contamination, see our water filter guide.
Boiling doesn't work for chloramine. It's chemically stable at boiling point. So if you're trying to remove it for coffee or tea, you need a filter, not a kettle.
Three ways:
You can also look at the full list of contaminants your utility tests for – if they report "monochloramine" or "total chlorine residual (with ammonia)," that's chloramine.
Affiliate Disclosure: This article contains affiliate links. If you purchase through them, we earn a small commission at no extra cost to you.
Does chloramine cause lead leaching? It can, if the utility doesn't adjust pH and add corrosion inhibitors. Washington, D.C.'s 2001-2004 lead crisis was partly caused by switching to chloramine without adequate corrosion control. But chloramine itself doesn't cause lead leaching – it's the lack of corrosion control that does. When managed properly, chloramine doesn't increase lead levels.
Can I remove chloramine by leaving water out overnight? No. Chloramine is too stable to off-gas in a reasonable timeframe. It takes days to weeks for chloramine to break down naturally in an open container, and even then it doesn't fully evaporate the way chlorine does.
Is chloramine worse for your skin and hair? Possibly. Some people report dry skin, brittle hair, or eczema flare-ups after their utility switched to chloramine. The science here is thin – most dermatology studies focus on chlorine in pools, not chloramine in tap water. If you suspect this is an issue, a shower filter with catalytic carbon can remove it.
Why don't utilities just use ozone or UV instead? Some do, but ozone and UV don't provide residual disinfection. They kill pathogens at the treatment plant, but they don't keep water disinfected as it travels through miles of pipes to your home. Chlorine and chloramine provide that residual protection.
Do I need to filter chloramine out? That depends on what you care about. If you dislike the taste or smell, yes. If you're on dialysis or have an aquarium, yes. If you're just drinking it and have no health conditions that require chloramine removal, the EPA considers it safe at regulated levels.