What is backflow?
–Back-siphonage occurs when a sudden drop in pressure causes suction of used or contaminated water back into the water supply. For example, let’s say a homeowner uses pesticide in their lawn, then waters the yard and water pools around a sprinkler head. Then the fire hydrant down the street is used, causing a sudden drop in water pressure. The water around the sprinkler head can be sucked back into the potable (public) water supply, contaminating the community’s drinking water supply. Back-pressure occurs when water is forced to flow in the opposite direction due to pressure downstream increasing the system pressure.
A backflow preventer can be installed on your home’s pipes. It prevents water from being siphoned or forced back into the potable water supply. Backflow preventers are mechanical in nature and have many moving parts which have a higher potential to malfunction than non-moving pieces – so you should have your backflow preventer tested annually to ensure that it is functioning properly. If your backflow preventer is not functioning properly, it must be repaired.
3 Types of Backflow Preventers
There are three types of backflow preventers – pressure vacuum breaker assemblies, reduced pressure zone assemblies and double check valve assemblies.
- Pressure Vacuum Breaker Assemblies
The most commonly used assembly is the pressure vacuum breaker, which has the simplest design – making them easy to install, maintain and repair. This assembly prevents back-siphonage only, not back-pressure.
- Reduced Pressure Zone Assemblies (RPZ)
RPZs are the most complex and expensive backflow preventers but, when functioning properly, are most reliable. This type of backflow preventer can be installed either above or below ground, although above ground is preferred, and protects against both back-siphonage and back-pressure.
- Double Check Valve Assemblies (DCA)
Double check valve assemblies are the best option for underground or indoor installations. DCAs are the most commonly approved underground backflow preventer, although they can also be installed above ground, depending on the installation code for your area.
If you’re unsure if you have or need a backflow preventer, need your existing backflow preventer tested or need it repaired or replaced, give us a call and we can help!