How to Prevent Sewage Backup During Basement Flooding

LESLIE: Ed in Colorado is on the line with a basement-plumbing question. What can we help you with today?

ED: Oh, I live in the area of Colorado that suffered from the floods. Fortunately, I wasn’t one of the persons that had a flood but some of my friends that did have had sewerage backup in their basements. And somebody mentioned that there was such a thing as a check valve that can be installed that still lets it act as a drain but will stop any backups. And I was wondering if you have a recommendation, if there’s any problem with them that you know of.

TOM: Yeah, Ed, that’s called a “backflow preventer valve” and it’s a type of valve that is installed in the main waste line. And it does just what you explained. If the sewage flow reverses and there’s pressure onto the sewage pipe to kind of pump that sewage back into your house – which can get terrible because it can come up through every drain in the house – the backflow preventer valve will stop that from happening.

But just keep in mind that it’s not to be confused with the sewer trap, which stops sewage gas from backing up. You actually need the sewer trap but you also need the backflow preventer valve, especially if you have an area that apparently is susceptible to this.

So I think it would be a good thing to do. You’re going to need a plumber to install it. It’s a bit of a project because you’ve got to get access to the line to do it but it is a good idea to have it done.

ED: Do I have access through the drain and the little screen that’s over the top of it?

TOM: Well, the line has to be actually – this is a valve that has to be plumbed into it, so it depends on whether or not there’s enough room to kind of move the pipes around to get this backflow preventer valve in there.