What is Backflow? It is the undesirable reversal of flow of water or mixtures of water and other liquids, gases or other substances into the distribution pipes of the potable supply of water from any source or sources. In other words contamination of your drinking water.

What is Cross-Connection? Any unprotected actual or potential connection or structural arrangement between a public or a consumer's potable water system and any other source or system through which it is possible to introduce into any part of the potable system any used water, industrial fluid, gas or substance other than the intended potable water with which the system is supplied. Examples would be hooking a garden hose to an insectiside sprayer or putting the hose in the car radiator without some kind of backflow protection device.

What is Backsiphonage? A form of backflow due to a reduction in system pressure which causes a subatmospheric pressure to exist at a site in the water system. Most common cause is when there is a fire and the fire department starts pumping water out of the mains causing a drastic reduction in main line pressure that can siphon water right out of your pipes back into the city main if a preventer doesn't exist!

How is backflow caused? It exists whenever the pressure in your water lines exceed the pressure in the cities supply lines. This can be caused by city pumps going out, fire department depleting pressure due to fire fighting, a pump on a customers site reversing the flow of water pressure and many other ways.

What does the law require? Where it is possible that a pollutional, contaminant, system or plumbing hazard may be created by a water user an approved backflow prevention assembly of the proper type should be installed.