Total Haloacetic Acids (HAA5)
HAA5 is the sum of five haloacetic acids formed when chlorine reacts with organic matter. Unlike trihalomethanes they are non-volatile, so they are an ingestion concern rather than a shower concern. The EPA limits HAA5 to 60 ppb (0.060 mg/L).
EPA MCLG Level
0 mg/L
Maximum level that poses minimal health risk based on the latest science
Health Effects
Long-term exposure is associated with an increased cancer risk; dichloroacetic acid, one of the five, is classified a probable human carcinogen. The risk is chronic and lifetime rather than acute.
Common Sources
- Byproduct of disinfecting drinking water with chlorine
- Formed when chlorine reacts with natural organic matter such as decaying leaves, runoff, and algae
- Levels are highest in warm-season surface water
Is your Total Haloacetic Acids (HAA5) result safe? Get a free reading
The EPA MCLG for Total Haloacetic Acids (HAA5) is 0 mg/L. Upload your water test (PDF or a photo) and we'll email a plain-English reading of where your result lands — and every other number — free. Educational only, no medical claims.
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Water filters certified under the following NSF standards are effective at removing Total Haloacetic Acids (HAA5):
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Where is Total Haloacetic Acids (HAA5) Found?
Total Haloacetic Acids (HAA5) has been detected above EPA health guidelines in 3 cities serving 0.0M people across the US.
EPA MCLG Level
The EPA MCLG represents the maximum level that poses minimal health risk based on the latest scientific research. It's often more protective than federal legal limits.
Contaminant Type
Total Haloacetic Acids (HAA5) is classified as a Disinfection Byproducts contaminant.
Related Disinfection Byproducts Contaminants
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