Frequent Questions

What chemical contaminants are regulated by the haloacetic acids (HAA5) standard? Are there individual maximum contaminant levels (MCLs) or maximum contaminant level goals (MCLGs) for these contaminants?

Five haloacetic acids (HAA5) are regulated under the Stage 1 Disinfectants and Disinfection Byproducts Rule (Stage 1 DBPR). The MCL for HAA5 is the sum of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, and dibromoacetic acid. The HAA5 MCL is 0.060 mg/L. Two of the HAA5 have individual MCLGs but there is no collective MCLG for this group (40 CFR 141.53). The individiual MCLGs are zero for dichloroacetic acid and 0.3 mg/L for trichloroacetic acid (63 FR 69390, 69396; December 16, 1998).
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