Chloroform

Category: disinfection byproduct

Written by WaterFilterMatch Editorial TeamApril 2026

EPA MCL

Not regulated

Status

EPA Regulated

NSF Standard

NSF/ANSI 53

Health Effects

Classified as a probable human carcinogen (Group B2) by EPA. Associated with liver and kidney damage, central nervous system effects. Most abundant trihalomethane in chlorinated water.

Source: EPA National Primary Drinking Water Regulations

Where It Comes From

The most common trihalomethane formed during water chlorination. Part of the TTHM group - regulated under the Stage 2 Disinfectants and Disinfection Byproducts Rule as a component of total trihalomethanes.

Where It's Commonly Found

Present in virtually all chlorinated water. Typically the dominant THM species. Higher levels in warmer water with high organic content.

No individual MCL - regulated as part of TTHMs (0.080 mg/L for total). Individual MCLG is 0.07 mg/L. Found in nearly all chlorinated public water systems.

How to Remove It

Effective Technologies

  • activated carbon
  • carbon block
  • reverse osmosis

Does NOT Remove It

  • UV
  • ion exchange
  • water softener
  • mechanical filtration

Official Sources

Related Contaminants

Learn More

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Informational guidance based on EPA data and NSF standards - not medical advice.