1. “Approved air gap” means a physical separation between the free-flowing end of a potable water supply pipeline and the overflow rim of an open or nonpressurized receiving vessel. To be an air gap approved by the department, the separation must meet the dimensions defined in WAC 246-290-490.

2. “Auxiliary supply” means any water source other than the public water supply that may be available in the building or on the premises.

3. “Backflow” means the undesirable reversal of flow of water or other substances through a cross-connection into the public water system or consumer’s potable water system.

4. “Approved backflow preventer” means an approved air gap, an approved backflow prevention assembly or an approved atmospheric vacuum breaker. The terms “approved backflow preventer,” “approved air gap” and “approved backflow prevention assembly” refer only to those approved backflow preventers relied upon by the city’s cross-connection control specialist for the protection of the public water system.

5. “Backpressure” means a pressure (caused by a pump, elevated tank or piping, boiler or other means) on the consumer’s side of the service connection that is greater than the pressure provided by the public water system and which may cause backflow.

6. “Backsiphonage” means backflow due to a reduction in system pressure in the city’s distribution system and/or consumer’s water system.

7. “The city of Monroe” is the authority having jurisdiction, in regards to this chapter, to administer and enforce the provisions upheld in the city’s cross-connection control program.

8. “Cross-connection” means any actual or potential physical connection between a public water system or the consumer’s water system and any source of nonpotable liquid, solid or gas that could contaminate the potable water system.

9. “Cross-connection control program” means the administrative and technical procedures the city of Monroe implements to protect the public water system from contamination via cross-connections as required in WAC 246-290-490 as defined in WAC 246-290-010. Cross-connection control program requirements are found in the city’s Cross-Connection Control Manual.

10. “Cross-connection control specialist” means a person holding a valid cross-connection control specialist certificate issued under WAC 246-290-292.

11. “Fire system” means a wet or dry piping system that can either be categorized as a closed, flow-through, or combination.

12. “Premises isolation” means a method of protecting the public water system by installation of air gaps or approved backflow prevention assemblies at or near the service connection or alternative location acceptable to the city’s cross-connection control specialist to isolate the consumer’s water system from the city’s distribution system.

13. “Double check valve assembly” (DCVA) means an assembly composed of two single, independently acting check valves, including tightly closing shutoff valves located at each end of the assembly, and suitable connections for testing the watertightness of each check valve. This assembly shall only be used to protect against a non-health hazard.

14. “Double check detector assembly” (DCDA) means a specifically designed assembly composed of a line-size approved double check valve assembly with a bypass containing a specific water meter and an approved double check valve assembly. The meter shall register accurately for only very low rates of flow up to three gallons per minute (gpm) and shall show a registration for all rates of flow. This assembly shall only be used to protect against a non-health hazard. This assembly is primarily used on fire sprinkler systems.

15. “Reduced pressure backflow assembly” (RPBA) means an assembly incorporating two check valves and an automatically operating differential relief valve, located between the two shutoff valves, and equipped with necessary appurtenances for testing. This assembly may be used for non-health and health-hazard applications.

16. “Reduced pressure detector assembly” (RPDA) means a specifically designed assembly composed of a line-size approved reduced pressure backflow assembly with a bypass containing a specific water meter and an approved reduced pressure backflow assembly. The meter shall register accurately for only very low rates of flow up to three gpm and shall show a registration for all rates of flow. This assembly shall be used to protect against a non-health hazard or a health-hazard. The assembly is primarily used on fire sprinkler systems with chemical injection. (Ord. 016/2021 § 2; Ord. 002/2012 § 1; Ord. 784, 1985)