What Backflow Is and Why It Must Be Prevented

The New York City Department of Environmental or DEP is responsible for providing potable water to more than nine million people. Therefore, NYC backflow preventer testing is legally mandated for certain businesses and highly advised for many other businesses and residences. So, what is backflow, what are the risks associated with it and how is it prevented?

Types of Water

There are three primary categories of water: potable, gray and black. Potable water is sometimes called white water to keep with the color naming convention. This is the water that is safe to drink. Gray water has been infused with chemicals and may be safe for plants at low levels is but generally deemed unsafe for humans to drink or even bathe with. Black water has been contaminated with organics, such as fecal matter, and it can provide a serious risk to all life.

What Is Backflow?

In the context of plumbing, backflow is an undesired reverse flow of water. Your washing machine draws water from the main water supply for your home. During use, that white water becomes gray, and should backflow occur, then you would experience contamination of your supply. In commercial environments, the scale and seriousness can threaten the water supply for an entire city.

How Is Backflow Prevented?

The most common way to prevent backflow is with an aptly name backflow preventer. A backflow preventer is positioned along the water supply. After water has passed through it, it cannot flow in the other direction, and this can be achieved as simply by maintaining an air gap.

Why Must Backflow Prevention Devices Be Tested?

Prevention devices comprise valves and other parts that will wear out over time and need to be replaced. If the device configuration is not precise, you can experience leaking or, worse, the prevention can fail outright, and you can experience backflow. When backflow prevention is legally mandated, most jurisdictions require annual testing.