A reverse osmosis system does remove chloramine, but not with the part people assume. The carbon stages do nearly all of the work; the membrane contributes little and is actively damaged by chloramine that reaches it. That distinction decides how you maintain the system and how long the expensive part lasts.
Chloramine is not chlorine with a different name
Chloramine is chlorine combined with ammonia, used by many utilities because it persists further through the distribution network and forms fewer disinfection byproducts. That persistence is exactly what makes it harder to remove: it does not gas off if you leave a jug on the counter, and it does not clear with a quick boil. It is also the reason some households notice a swimming pool smell that plain chlorine treatment would not leave.
Carbon does the removing
Activated carbon reduces chloramine, but more slowly than it reduces free chlorine, so contact time is everything. A large carbon block or a catalytic carbon specifically made for chloramine will do the job; a small, fast prefilter may not. Catalytic carbon is the upgrade worth paying for on a chloraminated supply, and on a whole-house system it means a properly sized bed rather than a token cartridge.
The membrane needs protecting, not credit
Thin film composite membranes are degraded by chlorine and chloramine. Once oxidized the damage is permanent and shows up as a steady rise in the dissolved solids of the product water. So the carbon prefilter is not a taste refinement in a reverse osmosis system on a chloraminated supply, it is the component keeping the membrane alive. Change it on schedule even if the water still tastes acceptable, because carbon loses its capacity for chloramine before it loses its capacity for taste.
Check whether you even have chloramine
Every community water system publishes an annual Consumer Confidence Report and the EPA maintains a finder for it, and that report names the disinfectant your utility uses. Reading it first is worth ten minutes: if the supply is chlorinated rather than chloraminated, a standard carbon block is plenty and the catalytic upgrade is money spent for nothing. Vendors list stage configurations and prefilter types on their own system pages, so shortlist against what your utility actually doses.
Questions people ask about does reverse osmosis remove chloramine
Will a basic carbon pitcher remove chloramine?
Only partly. Pitchers give short contact time, and chloramine needs longer contact or catalytic carbon to be reduced dependably.
Does boiling or standing water remove chloramine?
No. Unlike free chlorine, chloramine is stable and does not gas off usefully when water stands or is briefly boiled.
How often should I change the carbon prefilter on a chloraminated supply?
Follow the manufacturer's rated volume or interval and do not stretch it. The prefilter is what stops chloramine reaching and destroying the membrane.