What’s a Backflow Preventer And When Do You Need One?

Backflow preventers are valves that are installed on your home’s plumbing supply line or an irrigation water supply line that allows water to flow only in one direction but never in the opposite direction. The purpose of its design is to prevent possible contaminated water from flowing into your city’s drinking water supply lines.

But just what is “backflow”  when it refers to plumbing? Is this something the average Charlotte homeowner needs to worry about?

Never fear, we’ll answer these questions and more in our written guide blow to Backflow Preventers. To begin, let’s look at how contamination from backflow can occur.

What Causes “Backflow” To Occur?

When the water supply from a well or city water enters your home, it should only ever go in one direction. But sometimes due to pressure changes and other circumstances, that water can be prone to flow in reverse in the supply lines.

One example is backflow can happen when there’s an accidental break in the main water line or when a fire hydrant is used. Because of lost or reduced pressure during these events, the water is no longer pushed into the direction of your home and can actually flow back into the city supply.

If this happens, unclean water backflow can potentially contaminate the public drinking supply with:

• Human waste
• Fertilizers/pesticides
• Soap from sinks/dishwashers/showers
• Chlorine from pools/spas

And that’s where a backflow prevention system comes in handy. In some cities like Charlotte, for certain applications like irrigation to your lawn, it’s actually mandated that you have a backflow preventer installed with an inspection and permit. Let’s take a closer look at how a backflow prevention system works.

This is Why A Backflow Prevention System Prevents Backflow

Backflow prevention systems are devices installed into your water supply that only allow water to flow only in one direction.

You can think of the backflow preventer as a one-way gate that allows water from the city’s public water supply to flow into your home but stops water if and when it ever tries to flow back into the main water supply.

Here’s a diagram of how a Backflow Preventer works

So When Do You Need A Backflow Preventer Installed?

Firstly, Charlotte residents who have an irrigation system or a well are required to install a backflow preventer at their water meter (because both systems are at risk of contamination due to backflow).

Do you live somewhere else? Or are you a Charlotte resident without an irrigation system or well? If so, you’re probably wondering if you need a backflow preventer installed at your home at all.

The general recommendation, in that case, is you have a backflow preventer installed anywhere the water supply and any wastewater might be cross-connected should a backflow occur.

Some new construction homes may have built-in backflow preventers on certain water lines but in order to know for sure if your house has proper backflow preventers set up, we suggest having a plumber inspect your home’s plumbing system. They’ll install a backflow prevention system where it’s needed.