PureCityLearnChloramine in Drinking Water: What It Is, Why Cities Use It, and Why Your Brita Won't Remove It

Chloramine in Drinking Water: What It Is, Why Cities Use It, and Why Your Brita Won't Remove It

More than 1 in 5 Americans drink water treated with chloramine instead of chlorine — and most filters designed for chlorine won't remove it. Here's what chloramine is, what the health evidence says, and what filtration actually works.

If your tap water smells or tastes like chlorine but your utility's annual report says they use "chloramine" -- that's not a contradiction. Chloramine produces a similar chemical smell to chlorine, but it's a different compound that behaves differently in your water and requires different filtration to remove.

More than 113 million Americans receive water treated with chloramine. Most of them don't know it. And many people who have filters installed for taste and odor are using filters that don't meaningfully reduce chloramine.

Here's what you actually need to know.


What Is Chloramine?

Chloramine (technically monochloramine, the form used in water treatment) is produced when water utilities add ammonia to chlorine. The resulting compound disinfects water and stays stable in the distribution system as water travels through miles of pipes to your tap.

That stability is the main reason cities use it. Chlorine is an excellent disinfectant at the treatment plant, but it dissipates relatively quickly. For large cities with long distribution systems, chlorine levels can drop too low by the time water reaches the end of a long pipe run. Chloramine maintains its disinfecting power longer.

How to find out if your water uses chloramine: Check your utility's annual Consumer Confidence Report (CCR), published by July 1 each year. It will list the disinfection method. You can also call your utility directly or check the EPA's ECHO database. If you want certified lab confirmation of what's actually in your tap water including chloramine levels and byproducts, the Tap Score Essential City Water Test covers disinfection byproducts alongside 50+ other parameters. See our complete water testing guide for more detail.


Why Did So Many Cities Switch?

The shift to chloramine accelerated after EPA's Stage 1 and Stage 2 Disinfectants and Disinfection Byproducts Rules tightened limits on trihalomethanes (TTHMs) and haloacetic acids (HAA5) -- the byproducts formed when chlorine reacts with organic matter.

Chloramine produces far lower levels of TTHMs and HAA5 than chlorine. So utilities facing compliance challenges with those DBP limits switched to chloramine as the solution.

The trade-off: chloramine produces different byproducts -- notably haloacetonitriles and, as confirmed by a 2024 study published in Science, a previously unidentified compound called chloronitramide anion. Researchers don't yet know if it's harmful; it's simply been detected now that analytical techniques are sensitive enough to find it.


Is Chloramine Harmful?

At the levels used in public water systems (up to 4 mg/L), chloramine is considered safe for healthy adults by the EPA and CDC. The evidence for harm at typical drinking water levels is not strong for the general population.

Where it is a problem:

Dialysis patients. The clearest, most serious concern. When water is used in dialysis machines, it contacts patients' bloodstreams directly through the dialysis membrane. Chloramine at any concentration can cause acute hemolytic anemia and methemoglobinemia in dialysis patients. Dialysis centers are required to remove all disinfectants from water before use.

Fish and aquatic animals. Chloramine is toxic to fish, reptiles, and amphibians at drinking water concentrations. Standard aquarium dechlorination products (sodium thiosulfate) that neutralize chlorine do NOT neutralize chloramine. Use products specifically labeled for chloramine removal.

Sensitive individuals. Some people report skin and eye irritation when bathing in chloraminated water. Chloramine is less volatile than chlorine -- it doesn't steam off in a hot shower the way chlorine does. People with eczema or other skin sensitivities may notice this.

The byproducts picture. Chloramine produces lower levels of regulated DBPs (TTHMs, HAA5) than chlorine -- that's why cities switched. But it produces different byproducts, some less studied. Nitrosamines, particularly NDMA (a probable human carcinogen), can form as a chloramine byproduct at low levels.


The Critical Filtration Problem

Standard activated carbon filters -- including most pitcher filters, Brita, PUR Standard, and typical faucet-mount filters -- do not effectively remove chloramine.

This is not a minor technicality. If you bought a filter because your tap water "smells like chlorine" and your water is actually treated with chloramine, your filter may be providing little to no improvement.

The chemistry explains why. Chlorine is removed by activated carbon through straightforward adsorption. Chloramine doesn't adsorb well to standard activated carbon. You'd need a very large quantity of standard carbon, or a very slow flow rate, to get meaningful chloramine reduction.

What actually works:

Catalytic carbon. A modified form of activated carbon with a more reactive surface chemistry specifically suited to chloramine. Catalytic carbon catalyzes the decomposition of chloramine into its components, then removes them. Filters using catalytic carbon are significantly more effective against chloramine than standard carbon.

Reverse osmosis. RO membranes remove chloramine -- typically 95--99%. However, chloramine can be harder on RO membranes over long periods, which is why many RO systems include a catalytic carbon pre-filter to protect the membrane.

Vitamin C (ascorbic acid). Relevant specifically for bathing -- neutralizes chloramine on contact. Used in some shower filters. Effective but the medium depletes and needs replacement.

What doesn't work: Boiling (chloramine is stable and does not evaporate like chlorine), letting water sit out overnight, standard carbon/Brita filters (minimal effectiveness at normal flow rates), and distillation.


Cities Known to Use Chloramine

Major US cities using chloramine include: Denver, Los Angeles, San Francisco, Philadelphia, Houston, Seattle, Portland, Milwaukee, San Jose, and many others. More than 1 in 5 Americans drink chloramine-treated water.

This is not the same as saying those cities have bad water. Chloramine is a legitimate, well-established disinfection method. But it matters for filter selection.

Enter your ZIP at PureCity to see what disinfection method your utility uses and what's been detected in your local water.


Filters That Remove Chloramine

APEC ROES-50 Under-Sink Reverse Osmosis System
Most Complete Protection
What We Like
  • Removes chloramine, chloramine byproducts, lead, PFAS, and virtually everything else
  • NSF 58 certified; WQA Gold Seal; made in USA
  • On-demand filtered water from a dedicated faucet -- no reservoir to refill
  • Most comprehensive protection for chloramine cities like Houston, Denver, Seattle
What To Know
  • Requires one drilled faucet hole and basic plumbing connection
  • Not suitable for renters without landlord approval
  • 4:1 waste water ratio
🔧
InstallationUnder-sink · DIY-friendly with basic plumbing skills · 1-2 hours · Requires drilling one faucet hole

The most thorough solution for chloramine-treated water. Removes chloramine and all its byproducts plus any other contaminants in your water -- the right choice if you want full coverage.

Frizzlife SK99 Under-Sink Water Filter
Best Catalytic Carbon Filter
What We Like
  • Catalytic carbon block specifically designed for chloramine removal
  • NSF 42, 53, and 372 certified -- covers chloramine, lead, and VOCs
  • No drilling required -- T-valve connection is fully reversible when you move
  • Best value for chloramine reduction without full RO
What To Know
  • Does not remove PFAS, nitrates, or arsenic the way RO does
  • Not suitable for pull-out or non-standard faucet configurations
  • Catalytic carbon capacity is finite -- replace on schedule
🔧
InstallationUnder-sink · No drilling required · T-valve connects to existing cold water line · 15 minutes · Fully reversible

The best under-sink option for renters or anyone who wants strong chloramine reduction without the cost or complexity of RO. If chloramine taste and byproducts are your main concern, this is the right pick.

Clearly Filtered Water Pitcher
Best Pitcher for Chloramine
What We Like
  • Certified for chloramine reduction -- one of the only pitchers that specifically addresses this
  • NSF 42, 53, 244, 401, and 473 certified -- also covers lead, PFAS, and 360+ contaminants
  • No installation required -- good for renters in chloramine cities
  • Best non-RO pitcher for comprehensive coverage
What To Know
  • Slower than a Brita -- around 10 minutes to filter a full pitcher
  • Higher ongoing cost than standard pitchers
  • Holds 10 cups -- may need frequent refilling for larger households
🔧
InstallationNo installation -- just fill and pour

The only mainstream pitcher with documented chloramine reduction performance. For renters in Denver, Houston, Seattle, or any chloramine city who want a no-install option, this is the one to get.

Bluevua RO100ROPOT-LITE Countertop Reverse Osmosis
Best No-Install RO
What We Like
  • Full RO chloramine removal without any plumbing
  • Also removes PFAS, lead, nitrates, arsenic, fluoride, and chromium-6
  • 3:1 pure-to-drain ratio -- more efficient than traditional RO
  • No landlord conversation needed
What To Know
  • Filters into a reservoir -- not on-demand tap flow
  • Takes up counter space; higher upfront cost than pitchers
  • Does not remineralize
🔧
InstallationNo installation -- portable countertop unit, plugs into standard outlet

For renters in chloramine cities who want comprehensive RO coverage without installation. Addresses chloramine and its byproducts plus everything else in one system.


The Bottom Line

Chloramine is a trade-off: it solves the regulated-byproduct problem better than chlorine, but creates different byproducts and requires different filtration. The key insight: check what your water utility uses before buying a filter, and make sure your filter specifically addresses the disinfectant in your water. A standard carbon pitcher will likely disappoint you if your city uses chloramine.


Related Articles


Sources: EPA Chloramines in Drinking Water · CDC Water Disinfection with Chlorine and Chloramine · Water Quality Association Chloramine Fact Sheet · NBC News: Newly Identified Chemical in Chloramine-Treated Water, November 2024 · NSF Certified Products Database