(a) The Department is authorized to require disinfection of:
(1) Public water systems introduced on or after January 1, 1972; and
(2) All public water systems, regardless of the date introduced, whenever:
a. The maximum microbiological contaminant level is exceeded; or
b. Conditions exist which make continued use of the water potentially hazardous to public health.
(b) Public water systems shall employ disinfection methods and procedures approved by the Department.