Backflow 101: Understanding the Basics of Common Backflow Prevention Devices


Backflow is a term o describe water flowing in the wrong direction into your home. In the case of backflow, dangerous contaminants can make their way into the water supply, causing a slew of health ailments. Because of the risks associated with backflow, many homeowners opt to install backflow prevention devices to alert them of the occurrence.

Understanding the Basics of Common Backflow Prevention Devices

There are several different types of backflow prevention devices. Let’s break down the basics of the two most common:

Double-check backflow preventers

Double-check backflow devices are the most commonly used. These devices have two layers of protection against backflow. Double-check backflow devices work well in residential, low-risk uses. Each of the two internal valves can hold up to one pound of backflow. However, if the backflow is more than the valves can handle, it can still make its way into the pipes. Hence, double check backflow devices are not ideal for “high-risk” locations. 

Reduced pressure zone backflow preventers

These devices are also commonly used to protect against backflow. Similar to double-check backflow devices, reduced pressure zone devices contain valves. In reduced pressure zone backflow devices, a third valve acts as an added barrier to backflow. If water is able to bypass the first two check valves, the third valve (open to the atmosphere) will open and drain. Because of this added layer of protection, reduced pressure zone backflow devices work well for high-risk locations. 

If you live in a high-risk location, it’s important to make sure that you have a backflow prevention device installed in your home’s plumbing system. To determine whether a backflow prevention device is necessary, it’s best to first contact the water supply company. They will be able to inform you of the risk level of your residence. If a backflow prevention device is deemed necessary, that’s where we come in.

Licensed plumbers in Los Banos, Turlock, Merced, and Patterson

To learn more about backflow prevention options for your home or for help with any other plumbing issue, give All American Plumbing, Heating & Air a call today at (209) 710-5629.