40 CFR 141.503 - What does subpart T require?
There are seven requirements of this subpart, and you must comply with all requirements that are applicable to your system. These requirements are:
(b) If your system is an unfiltered system, you must comply with the updated watershed control requirements described in §§ 141.520-141.522;
(d) If your system is considering making a significant change to its disinfection practices, you must develop a disinfection benchmark and consult with the State for approval of the change as described in §§ 141.540-141.544;
(e) If your system is a filtered system, you must comply with the combined filter effluent requirements as described in §§ 141.550-141.553;
(g) You must comply with the applicable reporting and recordkeeping requirements as described in §§ 141.570 and 141.571.