(A) The type of protection required under this subchapter shall depend upon the degree of hazard that exists as follows.
(1) An approved air gap separation or an approved reduced pressure principle backflow prevention assembly shall be installed where a public water supply system may be contaminated with any substance that could cause a system hazard or health hazard.
(2) An approved double check valve assembly shall be installed where a public water supply system may be contaminated with any substance that could cause a pollution hazard.
(3) An approved reduced pressure principle backflow prevention assembly shall be installed at the service connection where there exists a plumbing hazard.
(4) In the case of any premises where, because of security requirements or other prohibitions it is impossible or impractical to make a complete cross-connection survey of the customer’s potable water system, a reduced pressure principle backflow prevention assembly shall be installed at the service connection.
(B) An approved atmospheric or pressure vacuum breaker may be used as a backflow prevention assembly where it is not subjected to back pressures. The above assemblies shall be installed in accordance with the requirements of NACZ, Title 179, § 008.01E3.
