If there is a backflow preventer on your property, you’ll probably need to have it tested from time to time. State laws and ordinances vary, but in Tennessee, “All backflow prevention assemblies should be tested on at least a 12-month basis.”
Annual backflow testing is a routine procedure requiring plumbers to have the proper certification and to document the results of the test. If anything is found to be damaged, a valve may need replacement or you may need to replace the device.
But what makes this service so important? What would happen if your backflow preventer were to fail?
Backflow is the undesirable reverse flow of water through a piping system. Water should only go one way within the pipes, from the public supply into your property. But when something changes in the pressure of the water supply, you could have dangerous contaminants coming up through the pipes in the opposite direction.
One example of a situation in which backflow could affect the water supply is if a water pipe leads to a boiler. The boiler feed water may contain chemicals you don’t want in your drinking water. However, if the pressure builds up in the boiler (higher than the pressure of the water supply), it could potentially move backwards through the water supply.
Another example is a sprinkler system. Water and pesticides could pool up near your sprinkler heads, which typically is not a problem. However, if a firefighter needed to use a hydrant nearby, the water pressure in your supply could drop dramatically. This drop in pressure may allow pesticide water to get sucked back through the pipes, allowing for a dangerous contamination of the public water supply.
Even if you think your property could not be responsible for such a situation, it’s always a possibility. If a hose is submerged in something, you don’t want to be responsible for a potential water contamination situation in your community. The backflow preventer on your property has check valves that prevent such a situation. Be sure to call in licensed plumbers to test yours when you need it!