Two glasses of city water can taste noticeably different even when both are fully compliant — usually because of which disinfectant the utility uses to keep water safe on its way to you. Chlorine is the older, sharper-tasting choice. Chloramine, made by adding ammonia to chlorine, is the quieter, longer-lasting one — and considerably harder to remove at home, which is where most wasted filter purchases begin.
We have not hands-on tested the filters discussed here. What we have done is check the chemistry and removal claims against EPA sources and the certification standards themselves, so you can tell a filter certified for your disinfectant from one certified only for the other. First find out which your city uses — our what’s in my water tool is the fastest route. Background: the water quality hub.
Disclosure: TapChecked is reader-supported. If you buy through links on this page we may earn a commission, at no extra cost to you. It never changes which products we pick or how we rank them. See how we check and our full disclosure.
What chloramine actually is
The EPA’s definition is short: chloramines are disinfectants most commonly formed when ammonia is added to chlorine to treat drinking water. The form utilities intend to make is monochloramine. Chloramines have been used since the 1930s, and the EPA notes that more than one in five Americans uses drinking water treated with chloramines — a mainstream, long-established practice, not an experiment.
The key word in the EPA’s description is longer-lasting: chloramines provide longer-lasting disinfection as water moves through pipes to consumers. Utilities generally use chlorine first, as the primary disinfectant, and chloramine second — secondary disinfection — as the residual that must survive days in the system and still be working at the last house on the line. The federal ceiling is the same for both: a maximum residual disinfectant level of 4.0 mg/L, measured as chlorine.
Why utilities switch
The EPA states the compliance reason directly: some public water systems changed their secondary disinfectant to chloramines to meet disinfection byproduct requirements. When chlorine reacts with natural organic matter, it forms disinfection byproducts, and the regulated ones are capped — total trihalomethanes at 80 micrograms per litre, haloacetic acids at 60. Chloramine reacts less readily, so switching tends to produce fewer of them. The trade is stability against strength: chloramine is a weaker, slower disinfectant than free chlorine, which is why it is used as the residual rather than the primary treatment — and why it persists to your tap.
Why your water tastes different
Free chlorine announces itself: the sharp, swimming-pool note, fading as chlorine dissipates. Chloramine’s taste and odour are generally flatter and less sharp — but they do not fade the same way, because the disinfectant itself does not leave. Residual levels also vary with distance from the plant, so two households on one street can disagree. A sudden taste change often means a switch — some utilities temporarily return to free chlorine for system maintenance, a common cause of a “tastes like a pool again” month. Taste alone cannot identify your disinfectant; the report in the next section can.
How to find out which one your city uses
- Your Consumer Confidence Report. The annual water quality report names the disinfectant and lists its measured level against the 4.0 mg/L maximum residual disinfectant level. If the row says chloramine, that is your answer.
- Our ZIP lookup. The what’s in my water tool identifies your system, which is the name to search or to ask about.
- Ask the utility. Disinfectant type is basic public information; a short call or email settles it, including whether a temporary chlorine switch is in progress.
Do this before buying any filter — the removal question turns on it.
Why chloramine does not evaporate like chlorine
The folk remedies for chlorine taste — leave a jug standing overnight, or boil the kettle — work on free chlorine because it dissipates over hours. Chloramine was chosen specifically not to do that. EPA guidance treats standing at room temperature and ordinary boiling as not removing monochloramine; its residual decreases far more slowly than chlorine’s, slowly enough that utilities rely on it surviving the whole distribution system. The jug on the counter still tastes of disinfectant the next day because persistence is the design feature. If you want it out, you have to filter it out — with the right carbon, which is the next problem.
Removal: contact time is the whole game
Carbon removes chlorine quickly, in a fast reaction at the surface. Chloramine removal is slower: the carbon has to break the chlorine–ammonia bond, and that takes contact time — much more of it. Standard carbon sized for chlorine can let most chloramine through at normal flow. The media made for the job is catalytic carbon, treated to speed that reaction, typically in a larger bed so water stays in contact longer.
The worked math explains the sizing. Contact time is roughly bed volume divided by flow. One cubic foot of media is about 7.5 gallons of bed volume: at 5 gallons per minute the water gets about a minute and a half in the bed; at 10 gallons per minute, about 45 seconds. Halve the contact and chloramine reduction falls with it — why chloramine whole-house systems are physically big, why flow ratings matter more than brand names, and why a small cartridge that handles chlorine beautifully can do almost nothing here. Options that fit that physics are in our best whole-house water filters guide.
The certification trap: chlorine is not chloramine
Under NSF/ANSI 42, the aesthetic-effects standard, chlorine reduction and chloramine reduction are separate claims, tested and listed separately. A filter certified for chlorine taste and odour has been proven on chlorine only; certifier listings show exactly that split, and most carbon filters hold the chlorine claim alone. So “NSF 42 certified” on the box is the beginning of the check, not the end: open the certifier’s listing for that exact model and confirm the words chloramine reduction appear. How the standards divide the work is in NSF 42 vs 53 vs 58 vs 401.
At the tap, an under-sink system whose certification names chloramine — usually catalytic carbon or a long-contact carbon block, sometimes ahead of a reverse-osmosis membrane — is the proportionate fix. In the shower, be more sceptical. The shower-filter standard, NSF/ANSI 177, covers free available chlorine reduction only; there is no chloramine claim under it. Vitamin C shower filters are marketed for chloramine, but we found manufacturer claims rather than a certifier listing or independent shower test behind that promise — treat them as unproven for chloramine, however well they handle chlorine. Certified options are compared in our best shower filters guide.
Two groups who must remove it: fish and dialysis
The EPA is clear that water containing chloramines and meeting regulatory standards is safe for drinking, cooking, bathing and other household uses. Two exceptions are about water used differently. Chloramines, like chlorine, are toxic to fish and amphibians at the levels used for drinking water — aquarium water must be treated with a product that specifically addresses chloramine, not just chlorine. And water used in kidney dialysis must have chloramine removed first, because dialysis brings water into contact with blood across a membrane; dialysis facilities handle that treatment as part of their equipment. Neither exception changes the drinking-water conclusion — both are about water that is not being drunk.
Frequently asked questions
Is chloramine less safe than chlorine?
The EPA regulates both to the same maximum residual disinfectant level, 4.0 mg/L as chlorine, and states that water meeting the standards is safe for drinking, cooking and bathing. Utilities switch to chloramine mainly to stay within disinfection-byproduct limits. It is a different trade-off, not an unregulated one.
Will a standard pitcher or fridge filter remove chloramine?
Only if its certification specifically lists chloramine reduction under NSF/ANSI 42. Most are certified for chlorine only, and at pitcher flow and contact time, chloramine largely passes through a chlorine-only cartridge. Check the certifier’s listing for the exact model.
Can I just boil chloramine out, or let the water sit?
No. Those methods rely on dissipation, and chloramine’s stability is why utilities use it. EPA guidance does not treat standing or ordinary boiling as removing monochloramine.
Do I need to remove chloramine at all?
For health, per the EPA, no — water meeting the standards is safe to drink as delivered. Removal is a taste decision for most households, a necessity only for aquarium and dialysis water. If taste is the issue, match the filter to the disinfectant: catalytic carbon, and a chloramine claim on the certification.
The bottom line
Chloramine is chlorine plus ammonia, chosen because it lasts longer and forms fewer regulated byproducts. That stability defeats standing, boiling and chlorine-only filters. Find your disinfectant in your report, then buy only against a certification that names it.