(1) A cross-connection on a public water supply system must be eliminated by the disconnection of the cross-connection whenever reasonably practicable. Whenever elimination of a cross-connection is not reasonably practicable and the cross-connection creates a health or non-health hazard, the hazard must be eliminated by the insertion into the piping of an approved backflow prevention assembly or device in accordance with (2).

(2) For the cross-connections identified below, the following types of approved backflow prevention assemblies or devices must be used:

(a) A health hazard created by a cross-connection that may be subject to back pressure must be eliminated by an approved reduced pressure principle backflow prevention assembly (RP) or an air-gap.

(b) A health hazard created by a cross-connection that may be subject to back siphonage, but not subject to back pressure, must be eliminated by an approved air-gap, pressure vacuum breaker assembly (PVB), spill-resistant pressure vacuum breaker assembly (SVB), atmospheric vacuum breaker (AVB), or a reduced pressure principle backflow prevention assembly (RP).

(c) A non-health hazard created by a cross-connection that may be subject to back pressure and back siphonage must be eliminated, at a minimum, by an approved double check valve assembly (DC). This cross-connection condition may also be eliminated by an air-gap or by an approved reduced pressure principle backflow prevention assembly (RP).

(d) A non-health hazard created by a cross-connection that may be subject to back siphonage, but is not subject to back pressure, must be eliminated, at a minimum, by an approved double check valve assembly (DC), pressure vacuum breaker assembly (PVB), spill-resistant pressure vacuum breaker assembly (SVB), or an atmospheric vacuum breaker (AVB). This cross-connection condition may also be eliminated by an air-gap or by an approved reduced pressure principle backflow prevention assembly (RP).

(3) Backflow prevention assemblies and devices must be approved by the department.

(4) A backflow prevention assembly or device must be installed and maintained, at a minimum, in accordance with the manufacturer's specifications.

(5) This rule applies to piping between water systems outside of any building and to piping within any building, including cross-connections in plumbing systems.

(6) The department may not approve a plan for the construction of a public water supply system containing provisions for cross-connection unless provisions for the protection of the public water supply are demonstrated in the plan.