Why Your Basement Toilet Smells

Learn why your basement toilet smells worse than other toilets in your house from Master Plumber John Wood in this plumbing repair video from Howcast.

We’re gonna talk about why basement toilets seem to smell bad, worse than other toilets in the home. Okay?

There’s only one real reason. That’s because the basement may have suffered a clog in the past. Now when a clog happens, the water is going to back up out of the sewer into the lowest point in the house which is normally the basement toilet.

So let’s say this is your basement toilet. If there were a floor drain right over here it would come up out of the floor drain too because the floor drain is lower than the toilet but in this case the toilets the lowest one on the system. Okay?

So the water has no where to go. So this is my sewer pipe leaving the home for argument sake, okay? And for some reason, maybe roots or another reason we have a clog and now all this water that should be going down and out, it’s coming back this way. All right, and it comes back up.

It’s got one water tight seal here, this is the wax ring. You’ve probably seen a wax ring or maybe you haven’t below a toilet bowl. Now what happens normally when the toilet is not under what we call back pressure from the sewer this wax seal kind of squishes down. It makes a water tight seal between the porcelain of the toilet bowl and the iron flange that fits on top of the sewer pipe.

A lot of times what happens when the clog occurs is that this seal is blown out and we fix the clog and the seal is not replaced. So now instead of a nice clean wax ring around here blocking all the sewer gas from coming back in we’ve got a compromised waxed ring that’s not blocking sewer gas.

So the bad smell you’re getting from a basement toilet is most likely sewer gas. Another way that could happen is by perhaps a broken vent line but that’s very unusual. Normally speaking that’s why your toilet stinks in your basement.