401 KAR 8:510. Disinfection Byproducts
Samples shall be collected according to the approved sample site plan. Total residual samples shall be collected in tandem with 401 KAR 8:200 bacteriological monitoring. Compliance is calculated on a four-quarter running annual average with a maximum residual disinfectant level of 4 mg/L.
Here is information from EPA on disinfection byproducts.