Unpleasant smell in the bathroom

[seamlyne]

...and, no, it's not me.

We've been smelling something unpleasant in the main bathroom for a couple days now. It smells a bit like sewer gas, but lacks the characteristic strong rotten eggs smell of hydrogen sulfide, and none of us are experiencing (so far as I know) the usual symptoms associated with exposure (eye irritation, sore throat and cough, shortness of breath). It's just an unpleasant smell that appears to be coming from the bathtub drain.

I've run sufficient water to fill the trap below - it's a large-ish brass(?) cylinder - and we're going to experiment to try to isolate the cause. Here's what we know:

The toilet has water in the bowl, and unless it's leaking around the base - and there's nothing on the floor around it to indicate that it is - that's not it.

The trap under the sink has water in it.

Putting the stopper in the tub overnight seems to have helped, but the smell is cloying and might have seeped into the towels and other items in the room so it's hard to tell. We also ran the exhaust fan all night.

The tub has started draining slow - we noticed it about two weeks ago.

The laundry shares the same stack one floor below, and there is no smell coming from down there, so THAT trap has water in it.

Any advice, hints, previous experience?

[HayZee518]

seems you hit the nail on the head for the tub drum trap - it drains slowly

[seamlyne]

And now, the smell is gone. What's up with that? I probably shouldn't question my good fortune, and just be grateful.

So, we were smelling something from the drum trap?

[seamlyne]

Alright, the smell came back yesterday. I put the stopper in, and the smell dissipates. So, what's the story? A slow drum trap that somehow drains too much? Is there a fix I don't have to call a plumber for?

[nt4usb]

fwiw... I find a cup of bleach down the drain goes a long way to reducing odors.
Might give it a try.
It's a temporary fix until you get the drain cleared.

[HayZee518]

the drum trap has a brass cleanout cap on it. it may be buried somewhere in your floor

[rdgallo]

Where do you get a brass cleanout cap for the drum trap? I can only find the cheap pot metal ones that corrode through every 2 years.

Thanks!

[HayZee518]

go to a good reputable plumbing supply house. they should have a brass cleanout cap with a soft lead coating on the threads. It is a tapered thread in the lead

[rdgallo]

I have tried a couple of plumbing places around here and they say they do not have anything. Is there anyone on line selling them?

Thanks