A chloramine filter has to work harder than a chlorine filter, because chloramine is a stable bond of chlorine and ammonia that does not release on contact the way free chlorine does. Ordinary activated carbon removes it slowly and incompletely. The two things that decide whether your system works are the grade of carbon and how long the water stays in it.
Why chloramine is the harder target
Utilities use chloramine because it stays active far longer in the distribution network than free chlorine, holding disinfection all the way to the end of a long main. That same stability is what defeats a small carbon cartridge. Free chlorine reacts with carbon quickly and is gone. Chloramine has to be broken apart first, which ordinary granular carbon does only sluggishly, so water passes through carrying most of it, along with the flat chemical taste and the effect on aquarium life, dialysis equipment and sensitive skin.
Catalytic carbon and contact time
Catalytic carbon is activated carbon processed to have a much more reactive surface, and it is the standard media for chloramine because it breaks the chloramine bond rather than merely adsorbing. Even then the water has to stay in the bed long enough. That is a matter of media volume against flow rate, which is why a whole house chloramine system is built around a tall tank rather than a cartridge housing. Ask any vendor for the flow rating and the media volume together, because either number alone tells you nothing useful.
Whole house or point of use
If your concern is drinking and cooking, a catalytic carbon block under the sink, or a reverse osmosis system with a good carbon prefilter, is a modest and effective answer. If the reason is skin, hair or the smell during a shower, treatment has to be at the point the water enters the house, because a kitchen filter does nothing for a shower head. A shower filter is a middle option that helps with smell, though the very short contact time inside one limits how much chloramine any of them can genuinely take out.
Confirm chloramine is what you have
Not every utility chloraminates, and some switch between chloramine and free chlorine seasonally, which is a common cause of a filter that seemed fine suddenly failing on taste. Every community water system publishes an annual Consumer Confidence Report, and the EPA maintains a finder for it, so the report names the disinfectant in use. A total chlorine test strip at your own tap confirms it, since total chlorine reads chloramine while a free chlorine test does not. Our whole house water filter guide covers sizing the tank once you know the answer.
Questions people ask about chloramine filter
Does a standard carbon filter remove chloramine?
Only partly and slowly. Standard granular carbon is aimed at free chlorine, and chloramine passes through much of it, which is why catalytic carbon is the recommended media.
How do I know if my utility uses chloramine?
The annual Consumer Confidence Report names the disinfectant, and the EPA maintains a finder for it. A total chlorine test at your tap confirms what is arriving today.
Does reverse osmosis remove chloramine?
The carbon prefilter does most of the work, and chloramine damages the membrane, so systems on chloraminated supplies should use a catalytic carbon prefilter and change it on schedule.
Will boiling drive off chloramine?
Not usefully. Free chlorine dissipates with boiling or standing, but chloramine is far more stable and will largely remain, which is why aquarium keepers treat it chemically instead.