Backflow Preventers: What Are They & How Do Backflow Preventers Work?
Is Your Drinking Water Threatened by Backflow? It’s possible! Most times, water flows in a forward direction from your water supply source or water system into your main line and then into your home. Backflow is a term that describes the flow of water when it takes a backward direction and flows back into your water supply. Essentially, backflow happens when the water in your home (as the name implies) flows back into the public water supply. Backflow can also be caused when water that is flowing through a garden hose makes its way or flows back into your home’s water supply. Backflow is caused by back pressure or sometimes back-siphoning of the plumbing system. If the water is pure, backflow is not an issue. But if the water that flows back contains bacteria or chemicals, then it can lead to a dangerous or unhealthy situation.
A garden hose is a common cause of backflow, typically when a pesticide or fertilizer applicator is attached to the hose. When using these applicators, any drop in water pressure can cause the supply system to “suck up” those chemicals into the water in the hose. Without an effective backflow preventer in place, these chemicals can be present the next time you (or even one of your neighbors) turns on the tap. Water pressure drops are common in all municipal supplies. Once a backflow preventer is installed, water is unable to flow back into the public supply lines. This device effectively creates a closed plumbing system.
The backflow preventer is a device that prevents your water system from becoming contaminated from water flowing backwards into your supply lines. A backflow preventer is installed where the water main is routed into your home. It is also a good idea to install a backflow preventer if you have a sprinkler system. For this application, the backflow preventer would be installed where the sprinkle lines feed into the ground. A backflow preventer might also be known as an air gap.
How Does it Work?
A backflow preventer is simplistic yet ingenious in its design. It is comparable to the design of the heart valve in the human heart in that it allows the flow of water through one way and then closes when there is pressure coming back through. The way it works is simple. When water is pulled through the “main” line in your water system, such as when you turn on the tap in the kitchen, start a load of laundry, or flush your commode, the water is siphoned through a branch line. During this process, the water brings with it whatever is in the line. In the case of a sprinkler system, for example, you may be using weed killer, fertilizer, and so on, to take care of your lawn. Without a backflow preventer on the sprinkler system cut-in, your water system can inadvertently draw those toxins into your water supply.