Chloramine vs. Chlorine in Tap Water: What's the Difference?
How chloramine disinfection differs from chlorine and why it matters for filtration.
Most cities have switched to chloramine
Chloramine (a combination of chlorine and ammonia) is now used by the majority of large US water systems because it lasts longer in distribution pipes and produces fewer disinfection byproducts than free chlorine. However, chloramine is harder to remove and presents unique challenges for home filtration.
Why it matters for filters
Standard granular activated carbon (GAC) removes free chlorine effectively but struggles with chloramine. You need catalytic carbon for chloramine removal. This is a critical distinction when shopping for whole-house carbon filters. If your city uses chloramine and you buy a standard carbon filter, you may not get the chlorine removal you expect.
How to find out which your city uses
Check your city's Consumer Confidence Report or look up your city on CheckMyTap. Most cities list whether they use chlorine or chloramine. The taste and smell can also differ: chlorine has a sharp pool-like smell, while chloramine has a milder, slightly chemical taste.