If your utility uses chloramine, do not assume a filter designed only for free chlorine will perform the same. Verify the disinfectant in your consumer confidence report before buying whole-house carbon.
Why utilities use disinfectants
Disinfectants control microorganisms as treated water travels from the plant through miles of pipes. Chlorine has been used for more than a century; chloramine is used by many systems as a longer-lasting secondary disinfectant.
EPA states that water containing chloramines and meeting regulatory standards is safe for drinking, cooking and bathing.
Why chloramine is harder to filter
Chloramine is chemically more stable than free chlorine. Standard carbon can reduce it, but performance is more sensitive to contact time and carbon chemistry.
Catalytic carbon is commonly used when chloramine reduction is a primary whole-house goal.
How to find out what your utility uses
Check your annual Consumer Confidence Report or utility treatment page. Search for “disinfectant,” “chlorine,” “chloramine” or “monochloramine.”
Do not infer the disinfectant from taste or odor alone.
Treatment choices by use case
For drinking water, a certified point-of-use carbon or RO system may be enough. For shower odor, laundry and every tap, whole-house treatment may be more rational.
The correct scope depends on where the nuisance or contaminant exposure actually occurs.