Recently we purchased a new home. It was originally built in 1895 and was remodeled and gutted several times soon. Inspection was clean. We moved in and immediately noticed a sewer smell in the master bath.
Had a plumber come out, he cut open the wall by the tub and saw the tub was not trapped. He installed a trap on the tub. Since we intended to redo the shower soon, we did not touch it, instead we just put a airtight cap on the drain incase it also was not trapped.
Later we would discover that it was trapped wit a big 2inch trap already.
The smell went away and we hired a remodeling company to come build us a new shower.
Maybe 50% into their work, they removed the plug and the smell came back. Their plumber said it was because the trap was dry since the shower had not been used in a while.
We ran water. Smell persisted. We plugged the the drain in the shower but this time the smell persisted.
I assumed that they punctured the vent in the wall when installing the new concrete board, so I had them remove the drywall on the other side. Vent is fine, there is no damage, it is all sealed with the purple primer stuff. And there is no smell coming from inside the wall.
However, in the new shower, which is tiled floor, walls and cealing, you can still smell it.
The drain is plugged.
The vent pipe is installed correctly
All the other drains in the bathroom are trapped and the traps contain water, and i closed the drains on them all also.
The tub has been filled with water to rule out that. The overflow protector is taped off.
And yet ONLY inside the shower can you still sense the odor.
I am running out of ideas and I was wondering if anyone has any suggestions or thoughts that may help.
This is a true mystery.
We have done the pepper mint test with no rael results, and I will do a smoke test soon, but I am not sure it is going to uncover anything.
Thanks in advance for any ideas