(1) The purveyor shall ensure that reliability features are included in all water treatment facilities used to treat surface or GWI sources.

(2) Reliability features shall include but not be limited to:

(a) Alarm devices to provide warning of treatment process failures including coagulation, filtration, and disinfection. Alarm devices shall warn individuals responsible for taking corrective action and/or provide for automatic plant shutdown until corrective action can be taken;

(b) Standby replacement equipment available to assure continuous operation and control of coagulation, clarification, filtration and disinfection processes;

(c) Multiple filter units that provide redundant capacity when filters are out of service for backwash or maintenance, except where waived based on engineering justification acceptable to the department.

(3) The department may accept alternatives to the requirements specified in subsection (2) of this section, if the purveyor demonstrates to the department's satisfaction that the proposed alternative will assure an equal degree of reliability.