Backflow – Why It Happens and How to Prevent It

Posted: May 1, 2018 to Backflow Prevention

Water that is coming into the house should only flow one way. When it flows both ways, it can cause backflow. The fresh supply of water might be tainted with some contaminated water when the normal pressure in your system drops abruptly and the supply water flow reverses. This sucks water that is unhealthy from any of those cross-connected sources to your system of freshwater back into the supply of your drinking water.

These sources can be dishwashers, swimming pools, lawn sprinklers, toilet tanks, washing machines, or even garbage cans or gutters that you clean using your garden hose.

Why There is a Drop-in Water Pressure

There are different reasons why water pressure can drop. Common reasons are broken water mains, fire hydrants being opened, or a pumping station failure. When there is a huge loss of water pressure, the water might be drawn into that system at other spots nearby.

How Backflow Can be Prevented

First, you want to have a yearly inspection to detect any potential contamination sources. A plumber will be able to install different devices in your system anywhere the wastewater and fresh water could be cross-connected. So long as municipal water is flowing in just one direction, these devices are going to stay open. But if it reverses, the device will prevent water that is contaminated from going into your system.

There are two kinds of devices that may be used for residential applications:

Hose bib – This will protect one outlet such as a water faucet that is outside. This compact assembly has a spring that only allows water to flow in a single direction. If the water pressure drops, this spring will close and there is a valve that opens which will discharge that backflowing water so that it’s prevented from getting into your supply of freshwater.

Vacuum breakers (pressure type) – These are installed in that pipe that is supplying water to your sprinkler system and it constantly senses pressure in the system. If there is a drop in the system and it goes below the air pressure entering through an inlet above the ground, there is a check valve that will stop backflow.

Backflow can make you and your family sick. So you want to have your water checked if you have municipal water. It can help your family stay safe and healthy and keep your water clean and safe to drink.