Sewer Line Backflow Peventer

What is a backflow preventer?

As a Realtor helping people buy and sell homes in the Dayton area,  I’ve seen my fair share of unexpected surprises in homes, and one issue that often takes homeowners off guard is sewer backflow. This is when the sewer system reverses flow and comes back into the plumbing of the home. There’s a device that can stop this, and it’s not very expensive.  $25.00 to $50.00.  It’s called a backflow preventer.  

What types are there?

There are 2 basic types. A gate valve and a float. They both are simplistic devices. The gate valve is nothing more than a one way flapper door.  The door  lets water flow out, but shuts when water tries to reverse flow like what happens when the sewer backs up. The gate style  is for new construction to be installed in the floor prior to pouring the concrete.  

Float style uses a ball that allows water to pass as it goes down the drain and in the event of a backup at the street, the ball ‘floats’ upward and blocks the flow of water from making it to the interior of the home. This one is easier to install in an existing home. Remove your current floor drain cover and fit it inside the drain.  

Do all homes have them? 

Older homes generally won’t have these devices but they are great insurance. If you are in a new or newer home you may have noticed what looks like a 4 inch plastic disk on the floor, flush with the concrete floor. Hmmm, wonder what that is? That’s the maintenance cover to the valve so you check and maintain it. Whether you’re buying a new home or safeguarding your current one, understanding how a sewer backflow preventer works could save you from one of the messiest (and most expensive) plumbing problems you’ll ever face.