Frequently Asked Questions
What is a backflow preventer - A backflow preventer is a means or mechanism to prevent backflow. The basic means is an air gap, which either eliminates a cross-connection or provides a barrier to backflow. The basic mechanism is a mechanical backflow preventer, which provides a physical barrier to backflow. The principal types of mechanical backflow preventers are the reduced-pressure principle assembly, the pressure vacuum breaker assembly. A secondary type of mechanical backflow preventer is the residential dual check valve.
What is backflow - Backflow is the backward movement of normal water flow. This can result from a drop in the customer's water pressure or from suction in the water supply caused by a break in the water distribution piping. This can cause contaminants to drain back into the drinking water supply.
What is backsiphonage - Backsiphonage is backflow caused by a negative pressure (i.e. a vacuum or partial vacuum) in a public water system or consumer’s potable water system.
What is cross-connection - A cross-connection is a physical link between a potable water supply and any connection to a non-potable water source or apparatus. An example of a cross-connection is a drinking water pipe which is connected to contaminated source, such as chemical substances or well water without backflow protection.
Why do backflow assemblies have to be tested - Backflow assemblies have internal check valves, seals, springs and moving parts that are subject to wear or weakness over time. These assemblies need to be tested annually to ensure that they are working properly in protecting the water supply.