What rule that sets MCL's for harmful chemicals?

• A. Safe Drinking Water Act
• B. Disinfection Byproduct Rule
• C. Clean Water Act
• D. Radionuclide Rule

Answer: (B)

Disinfection Byproduct Rule sets specific maximum contaminant levels for harmful chemicals formed when disinfectants like chlorine react with natural organic matter in water. This rule targets disinfection byproducts such as trihalomethanes and haloacetic acids, providing the numeric limits utilities must meet to protect public health. The Safe Drinking Water Act provides the authority to set drinking water standards in general, but the actual MCLs for these byproducts come from the Disinfection Byproduct Rule. The Clean Water Act governs environmental water quality and discharges, not the drinking water MCLs, and the Radionuclide Rule focuses on radionuclides rather than the broader group of disinfection byproducts.