Authority Having Jurisdiction – The official, board, department, or agency authorized to administer and enforce the provisions of the Uniform Plumbing Code. In Tacoma, the Public Works Department’s Building and Land Use Services Office is the Authority Having Jurisdiction but Tacoma Water is responsible for cross connections.

Backflow – The undesirable reversal of flow of water or other substances through a cross-connection into the public water system or the consumer’s water system.

Backflow Assembly Tester (BAT) – A person certified by the State of Washington to test backflow assemblies.

Double Check Valve Assembly – A testable assembly approved for installation by the State of Washington Department of Health that consists of two independently loaded check valves and two resilient seated shut off valves.

Double Check Detector Assembly – A testable assembly approved for installation by the State of Washington Department of Health that consists of two approved double check valve assemblies arranged in parallel. The bypass assembly is equipped with a meter to detect leakage or water use.

High Health Hazard – A cross connection that could impair the quality of water and create a public health hazard through poisoning or spread of disease.

Low Health Hazard – A cross connection that could cause an impairment of the quality of water to a degree that does not create a hazard to public health but does adversely and unreasonably affect the aesthetic quality of the water.

Pressure Vacuum Breaker Assembly – A testable assembly consisting of an internally loaded check valve, an independently operating air inlet valve and two resilient seated shut-off valves.

Reduced Pressure Backflow Assembly – A testable assembly approved for installation by the State of Washington Department of Health that consists of two independently loaded check valves, a spring-loaded differential pressure relief valve and two resilient seated shut-off valves.