(1) All new residential and commercial facilities shall have both containment assemblies and internal-protection assemblies and devices. Containment assemblies shall be installed on the outlet side of the water meter.

(2) New facilities shall have the option to separate distribution mains for fire and domestic use, with a WSSC-approved backflow-prevention assembly on each branch.

(1) Containment assemblies and internal-protection assemblies and devices in facilities built before May 1, 2007, shall remain in service. Containment assemblies shall continue to be tested annually or repaired, and internal-protection devices shall be replaced every five years.

(2) Facilities built before May l, 2007, without containment or internal-protection backflow preventers and low-hazard facilities shall generally not need to be retrofitted, unless WSSC determines that retrofitting is warranted.

(3) WSSC shall require retrofitting if WSSC identifies high-hazard facilities without containment assemblies or if WSSC identifies high-hazard facilities with a type of containment backflow preventer(s) that is not commensurate with the degree of hazard.

(1) Backflow preventers shall conform to American Society of Sanitary Engineers (ASSE) standards as listed in the WSSC Plumbing and Fuel Gas Code.

(2) Application of backflow preventers as listed in the WSSC Plumbing and Fuel Gas Code shall be subject to field verification of hazards and conditions by WSSC. (Amended during 2019 codification; REG-REGS-EC-2014-004 § VI(A))