Many residents are often confused about Backflow and Backflow Prevention Devices (BPD)…so allow us to help educate you on this topic.
Backflow is the undesirable and hazardous reversal of flow of non-potable water or other substances through a cross-connection and into the piping of a public water system or consumer’s potable water system. Backflow can threaten the safety of the public water supply, which is why New York State has mandated the usage of prevention devices.
A backflow condition may arise when very low or negative street pressure occurs due to water main breaks, hydrants knocked over, etc. When these infrequent events present themselves, water in home and commercial plumbing systems might be siphoned backwards towards the street water main in the absence of a backflow prevention device (BPD).
Backflow Prevention Devices, when properly installed and maintained, guard against these conditions, so please check with our office regarding requirements when installing new plumbing systems including underground irrigation. Please note that underground irrigation systems are often mistakenly called sprinklers.
Your licensed plumber or irrigation system contractor is also knowledgeable about these requirements. If you have a BPD already installed on your plumbing systems, be sure to have it tested annually! Please take note that there are 3 types of BPD commonly used, 1 of which does not require annual testing:
- Reduced Pressure Zone (RPZ)
- Double Check Valve (DCV)
- Pressure Vacuum Breaker (PVB)*
*Irrigation systems using solely a PVB do not need to be tested annually, if no other backflow condition exists on the premises. An initial inspection is required, then subsequent inspections every five years.
Of special note, when winterizing underground irrigation systems, be sure the irrigation system is isolated from the potable feed line before using the air compressor to blow out the lines!
To properly install a Backflow Prevention Device, use the appropriate document below:
Need a few examples of why you need a backflow device?
Water pressure drops suddenly due to a nearby hydrant being utilized to extinguish a fire. Any water that has ‘puddled’ near the irrigation/sprinkler heads, where fertilizers are often present, could be siphoned back into the water supply that you and your neighbors rely on for drinking.
Since a situation where water pressure unexpectedly drops is not uncommon, backflow prevention devices must be used to stop back siphonage from potentially entering the public water system. New York State law mandates the installation of backflow devices on all appliances attached to the public water system such as:
- Underground Irrigation Systems (PVB)
- In-ground Swimming Pools
- Dark Rooms
- Solar Heating Systems
- Private Wells
- Hot Tubs
Most everyone that owns a pool uses the garden hose to fill it up. At the same time the garden hose is submerged in the water, the street water main ruptures thereby setting up a possible negative pressure condition to allow the back siphonage of the pool water. Of course there are many other conditions, including backpressure, which can pose a hazard to the potable supply.