Boiling can reduce free chlorine, but it is not an efficient household treatment for chloramine. For ongoing tap-water use, choose a filter specifically designed and tested for the disinfectant your utility uses.
Free chlorine is volatile
Free chlorine can dissipate from water with time, aeration and heating. Boiling accelerates that process, which is why chlorine odor can decrease.
Chloramine behaves differently
Chloramine is more stable and is intentionally used by utilities because it persists longer in distribution systems. Boiling is not an efficient practical strategy for routine chloramine removal.
Carbon is the practical household solution
Activated carbon can reduce free chlorine. Catalytic carbon is commonly preferred when chloramine is the primary disinfectant, especially at whole-house flow rates.
Check the utility first
Before buying a whole-house filter, confirm whether the utility uses chlorine, chloramine or seasonal conversions between them. The media and required contact time can change.