capping laundry room floor drain?

We had carpet professionally installed 1 1/2 years ago in our laundry/furnace/play area. The laundry drain was not capped and the drain recently dried up and sewer gas started to stick up the house.

I lifted the carpet and put water down the drain. That took care of the smell. We are afraid that we will ruin the rug and padding if we continue to lift up the padding and carpet in order to put water down the drain.

Is there a more permanent solution, so I dont have to keep on lifting the rug every time the drain dries up? The house was built in 1969. Thanks

Remove as much of the water from the trap as possible by sponging. Then push a rag into the drain leaving 3"-4" of space. Mix a batch of Fixall and fill that space full. If in the future you wanted to restore the drain, you would have to drill/chisel the Fixall out, but it could be done.

Pour mineral oil in the trap. It won't evaporate.

Would the antifreeze solution used to winterize mobile homes also not evaporate?

If you don't plug the drain, a drain clog could cause a backup that would come out under your carpet. I think the best thing to do is to seal the trap solidly.

How about a test plug?