N.C. Gen. Stat. § 143-215.66
In order to provide for adequately monitoring the discharge of wastes to the waters and the emission of contaminants to the outdoor atmosphere and their effects upon the quality of the environment, all persons subject to the provisions of G.S. 143-215.1, 143-215.108, or 143-215.109 who cause such discharges or emissions shall establish and maintain adequate water and air quality monitoring systems and report the data obtained therefrom to the Commission. Each monitoring system shall include the collection of water or air quality data as appropriate from such locations, in such detail, and with such frequency as required by rule of the Commission for evaluating the efficiency of treatment facilities or air-cleaning devices and the effects of the discharges or emissions upon the waters and air resources of the State.
N.C. Gen. Stat. § 143-215.66