Whenever a public water system:
(1) Is not in compliance with the drinking water rules;
(2) Fails to perform an applicable testing procedure or monitoring required by the drinking water rules;
(3) Is subject to a variance granted for inability to meet a maximum contaminant level requirement;
(4) Is subject to an exemption; or
(5) Fails to comply with the requirements prescribed by a variance or exemption,
the supplier shall as soon as possible, but not later than 48 hours after discovery, notify the Department and give public notification as prescribed by the drinking water rules.