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Haloacetic acids (HAA5) in drinking water

Also called HAA5, Haloacetic acids, HAAs.

Legal limit
60 ppb
Health goal
None

Values in parts per billion (ppb). Forms or is added in treatment.

Where the rules stand

Final MCL of 60 ppb (0.060 mg/L) for five haloacetic acids combined: monochloroacetic, dichloroacetic, trichloroacetic, monobromoacetic and dibromoacetic acid. EPA sets no health goal for the group as a whole. No NSF or WQA listing shows an HAA5 claim. NSF's VOC claim includes tribromoacetic acid, which is not one of the five.

The scale every TapBuff report uses for this contaminant: the legal line at the middle, twice it at the right.

What EPA says about health

EPA lists an increased risk of cancer from long-term exposure above the MCL.

Where it comes from

EPA calls HAA5 a byproduct of drinking water disinfection.

What handles it

No NSF/ANSI reduction claim exists for Haloacetic acids (HAA5), so no filter can be certified to remove it. Be wary of any product that says otherwise.

Sources

  1. National Primary Drinking Water Regulations, U.S. EPA. Checked Oct. 4, 2026.
  2. 40 CFR 141.2 Definitions (HAA5 and TTHM), eCFR. Checked Oct. 4, 2026.
  3. Search for NSF Certified Drinking Water Treatment Units (standards and reduction claims lists), NSF. Checked Oct. 4, 2026.
  4. NSF listings for the NSF/ANSI 53 "VOC Reduction" claim (footnote lists included chemicals), NSF. Checked Oct. 4, 2026.
  5. Find WQA Certified Products (Gold Seal listings by standard and claim), Water Quality Association. Checked Oct. 4, 2026.
  6. SDWA Dataset Download Summary (codes from SDWA_REF_CODE_VALUES.csv, 2026 Q2 extract), U.S. EPA ECHO. Checked Oct. 4, 2026.