industrialUnregulated by EPA

Phenols

Reviewed for accuracy against EPA data and peer-reviewed literature · Updated May 2026

A group of organic compounds containing a hydroxyl group attached to a benzene ring. Phenol and chlorophenols can enter drinking water through industrial discharge and as byproducts of chlorination reacting with naturally occurring organic matter.

CAS 108-95-2

EPA legal limit

No federal limit

Maximum Contaminant Level

EWG health guideline

No guideline

Science-based, stricter target

Health effects

Phenol is acutely toxic at high concentrations and causes taste and odour issues at very low levels. Chlorophenols formed during chlorination are of greater concern — some are suspected carcinogens. At the trace levels typically found in treated drinking water, health effects are uncertain.

Where it comes from

Industrial discharge from petroleum refining, plastics manufacturing, and pharmaceuticals. Chlorophenols form as disinfection byproducts when chlorine reacts with naturally occurring phenolic compounds in source water.

How it's regulated

No specific EPA MCL for total phenols. Individual chlorophenols are monitored under the Unregulated Contaminant Monitoring Rule.

How to filter phenols

Not all filters address phenols. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.

Activated carbon block filterNSF 53
Reverse osmosis (RO)NSF 58

Frequently asked questions

What is phenols?

A group of organic compounds containing a hydroxyl group attached to a benzene ring. Phenol and chlorophenols can enter drinking water through industrial discharge and as byproducts of chlorination reacting with naturally occurring organic matter.

What are the health effects of phenols?

Phenol is acutely toxic at high concentrations and causes taste and odour issues at very low levels. Chlorophenols formed during chlorination are of greater concern — some are suspected carcinogens. At the trace levels typically found in treated drinking water, health effects are uncertain.

Is phenols regulated in drinking water?

No specific EPA MCL for total phenols. Individual chlorophenols are monitored under the Unregulated Contaminant Monitoring Rule.

Where does phenols come from?

Industrial discharge from petroleum refining, plastics manufacturing, and pharmaceuticals. Chlorophenols form as disinfection byproducts when chlorine reacts with naturally occurring phenolic compounds in source water.

How do I remove phenols from tap water?

The most effective methods for removing phenols are: Activated carbon block filter, Reverse osmosis (RO). Look for NSF-certified systems—independent certification confirms removal claims have been verified.

Is phenols in your water?

Enter your ZIP code to see the measured level in your specific utility.