All customers are required to have a functioning backflow valve located downstream of the water meter. This backflow valve is part of the homeowner’s private plumbing. We want to take this opportunity to forewarn you that there is a possibility that the backflow preventer may cause your water system to "pop-off", due to thermal expansion. Most often this causes your hot water tank to pop-off and discharge through the relief valve on the tank. In certain cases the thermal expansion may affect, and damage, other parts of your plumbing susceptible to high-pressure. The control of thermal expansion is the responsibility of the individual homeowner, as it is caused by the homeowner's hot-water tank. In some cases, where the hot-water tank overflow pipe is properly drained, the occasional and small amount of "pop-off" water is acceptable to the customer. In other cases bursting pipes or excessive "pop-off" warrants a customer installing one of the thermal expansion control devices, typically a thermal expansion (diaphragm) tank. To learn more about thermal expansion and how to address this problem see the attachment below.
What is Backflow?
Means a flow condition induced by a differential in pressure that causes the flow of water or mixtures of water and other liquids, gases, or other substances into the distribution pipes of a potable water supply system from a source other than its intended source.
What is the most common offender?
Ironically, the ordinary garden hose is the most common offender as it can be easily connected to the potable water supply and used for a variety of potentially dangerous applications.
How can Backflow be prevented?
By installing a Backflow Preventer which is a device or other means which will prevent the backflow of water or liquids of questionable quality into the public water supply system.