floor drain check valves

I’m looking for some input on how/ what to report when you see a floor drain check valve; I’m talking about a little floating ball trapped in a cage that gets screwed into a floor drain to prevent back-ups. To me this indicates there was a problem with the drain backing up but I can’t prove this because the house has been winterized. Any thoughts would be appreciated.


Bruce Cargin

My thought, you are off track big time. I was told to install them to prevent the loop from evaporating over time, as a back up to a loop who can evaporate, and they also serve as a good seal for preventing migration of radon into a home.

The ball does nothing for reverse flow. NOTE: “since you do not have a photo, I’m guessing it’s not a ball check”

“Be the ball, be the ball…na na na”


More reading:




P.S. Went and got images for what I was talking about, since op was vague.

Floor drain backwater valve

Thanks Tom & Dale for your replies but that’s not what I’m looking at here. This is a plastic ball trapped in a threaded cage that threads into the floor drain after it is installed. The ball floats on the water in the trap and rises up to close off the drain when water tries to flow up/backwards through the drain. As a handyman I have installed several of these to prevent backflow from the heavy flow of a washing machine and they work very well.

Bruce Cargin
Hastings, MN
Gone for the holidays




I like reading material to support concepts, and options. Since I went down a road about a product I confused for what you asked, I thought I would follow up with a movie I found that might be what you are talking about.


P.S. A few g checks gave me this, is this what you meant?

P.S.S. We like photos here. :wink:

Could be a Dranjer product:


I think you nailed it Tom

We use to install a product years ago in a floor drain for the A/C condensate that was called by brand name Stinky Stopper fit into a cage simular to what your video showed but had nothing but a Ping Pong Ball inside that floated up when ever water was entering the drain when the water flow stopped the ball sealed the drain no dry trap sewer gas.

Hmmmm… Backflow preventer (of any kind) that reduces the 3" opening of a floor drain.
Usually, a ball check is for commercial applications and where the local system has ground water problems, etc. I would check with locals authorities to be certain.