Why chloramine suits a long trip
Chloramine is chlorine combined with ammonia. It breaks down more slowly than free chlorine, so it keeps protecting water through miles of mains and then through a building's pumps, tanks and risers. For residents on upper floors, that slow decay is part of how the water stays disinfected all the way to the tap. It is also why the smell can be noticeable in a hot shower.
The annual free-chlorine weeks
About once a year NMB Water switches the Norwood plant from chloramine to free chlorine and flushes hydrants. Its January 2022 newsletter described one such period, noting that system disinfection and hydrant flushing help maintain water quality for all customers. During those weeks the chlorine smell can be stronger, and brief discoloration is possible.
Why the usual fixes fall short
NMB's website suggests flushing cold taps for 5 to 10 minutes for three days, letting water sit overnight, or using a carbon filter to minimize chlorine taste. Those work well on free chlorine. Chloramine is more stubborn: it does not dissipate from a pitcher overnight the way free chlorine does, and it needs longer contact with the right media, usually catalytic carbon. That is why a small pitcher or shower filter rated only for chlorine may leave the smell. Our chloramine filter guide explains more.
Watch your rubber parts
NMB Water notes that chloramine may cause some plumbing fixture rubber to break down faster than normal. If o-rings, gaskets or toilet flappers fail within a few years, it recommends chloramine-resistant fixtures. Black specks in an aerator can be a sign, though NMB also lists spent carbon filters as a source of fine black particles.
Certification and options
- NSF/ANSI 42 listing that names chloramine, not only chlorine.
- NSF/ANSI 58 for reverse osmosis systems.
- Look up the exact model in the certifier's listing, with its rated flow and capacity.
| Property | Option |
|---|---|
| Condo unit | Under-sink RO with carbon stages for drinking water; chloramine-rated shower filter |
| House or townhome | Whole-home catalytic carbon system, often plus RO |
| Building | Central treatment, if the association chooses it |
Living Water describes its Puronics Clarius iGen and Goodspring whole-home systems as removing chlorine and chloramine; ask for the documentation on the exact unit quoted.
Check your current filter
Fill one glass from the tap and one from your filter, let them reach room temperature, and smell both. If the filtered glass still smells like a pool, the filter may not be rated for chloramine or may be spent. Jorge can measure total chlorine before and after it. Call, text or WhatsApp (305) 793-5974.
https://www.citynmb.com/DocumentCenter/View/14691/2025-CCR-ENGLISH-web-version
https://www.citynmb.com/917/Chlorine-Taste-and-Odor
https://www.citynmb.com/913/Black-Particles
https://www.citynmb.com/DocumentCenter/View/8844/Drops-of-Knowledge-January-2022
Updated 2026-10-17 · Living Waters · Jorge Canela, Water Quality Specialist