What is backflow?

Backflow is the reverse flow of non-potable water through a cross-connection and into the piping of a public water system or customer’s potable water system.  Two types of backflow are backpressure backflow and back-siphonage.

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What is back-siphonage?

Back-siphonage is backflow caused by negative pressure in a public water system or customer’s potable water system. Back-siphonage can occur when there is a stoppage of water supply due to a break in a water main, nearby firefighting, etc.

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What is a backflow prevention assembly?

A backflow prevention assembly is a mechanism to prevent backflow. The basic mechanism for preventing backflow is a mechanical backflow preventer, which provides a physical barrier to backflow.  The principal types of backflow preventers are the pressure vacuum breaker assembly, reduced-pressure principle assembly and the double check valve assembly (see image below).

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Why do I need a backflow device and why does it need to be tested?

These devices safeguard the public drinking water and protect the health of its residents. They do this by helping to ensure that any contaminants that could backflow into the public water supply system are isolated within the internal distribution system.

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Most water districts in New York State require each customer to  have a backflow prevention device installed on either the house water main or sprinkler system feed. They require that your device be tested annually.