Smelly plumbing issue

I don't know if there are any plumbers here or not, but maybe someone can chime in.

One of my bathrooms smells like a sewer pipe. The other two don't.

I replaced the wax seal under the toilet a few weeks ago and it seemed to help for a while, but now it's back full-force.

What could the problem be? I don't think I installed the wax ring that badly (what is there to screw up?), but I'm not going to totally discount it. But if there's some other reason this might be happening, I'd like to know.

I know if (and, probably, when) I call a plumber, he's going to come out and just replace the wax ring, despite the fact that I will have told him that I've already done it. So I'd like to avoid that if possible.

I'd never heard of these wax rings before so I felt compelled to investigate further. I found this article which explained it nicely.

A couple of observations...

The guy in the article mentioned using a deluxe ring that incorporates a plastic funnel that prevents water leaking if the wax seal's integrity isn't 100%.

From reading between the lines it looks like you need to bed the porcelain on the wax just enough to sit flat and sealed, but not so much so that the wax is deformed beyond where it seals completely.

I would get your plumbing vent pipes snaked out.

http://www.naturalhandyman.com/qa/qasinkdrainodor.html

Not too long after I posted this, I noticed that the water level in one toilet bowl fluctuated when I flushed the other, which led me to the same conclusion about the vent. As it turns out, my wife already called a plumber, so I told her what to tell him. I may write it down.

For the record, I had the worst installed wax ring in history on one of my toilets. Never had a problem with bad smell. Definitely check vent pipes and traps.

Now when the water in the clothes washer smells like sewer, that's what I'm stumped on.

You know what they say...

Sewer in, Sewer out.


Edit... Check the trap to see that water is staying in it. There is a P-trap in your washing machine's outlet, isn't there?