Some homes and businesses can at times experience something called backflow. This is the term used for the event when water goes the wrong direction through your sewage pipes. This is very serious since it can cause plumbing fixtures to back up, as well as, contamination of your water. If this happens it can lead to very serious sickness.
Backflow can be caused by back-pressure in the plumbing system, such as, when there is a broken water main or when the fire department uses large amounts of water for fighting a fire. It can also be caused by back siphonage when there is a vacuum in the water supply line.
To prevent it from happening, there are devices called atmospheric vacuum breakers. These are fairly inexpensive compared to other devices that are used for backflow prevention, and they last a long time. If you have an atmospheric vacuum breaker and notice water leaking from the top of it, it means that it failed and should be replaced as soon as possible.
