I might have posted about this problem before? In our basement in our laundry room we have a floor drain, which I assume most households would have, and we periodically get a sewer smell from it. My routine has been to fill a bucket with hot water with some dish soap, vinegar, bleach, etc then dump it down the drain. I assumed due to lack of use, the P trap was drying out. Today, looking further into things, I did some reading about a clean out hole and noticed the ones I seen all had a cap on them to stop sewer smells from coming back into the house. In these pics you will notice ours doesn't but you can also see what looks like weeping tile inside this side pipe/clean out spot so I am stuck wondering what to do? The floor opening drain is 4 inches as is the clean out hole. I am confused on this inner weeping tile and what it's purpose is? What I am afraid of is, if I block/cap this hole and because of the weeping tile, will I be blocking something off? Could this possibly be from our outside weepers and could they possibly drain to this floor drain? I have never heard water draining into it but that doesn't necessarily mean it doesn't, does it? So if this is just an inner weeper for some reason and it doesn't drain from here, what can I use to block/cap this off? My dilemma is both holes are 4" inches. Is there something that is available that I will be able to get down there, turn 90 degrees then cap this clean out hole off? I've looked at a few plugs but because both holes are the same size, it is going to be difficult (maybe?) to get something down there to do this.