Toilets, Sinks, Showers, Tubs and Disposals - Bathroom odor

Hi,

Ok, I'm stumped. Last November, I noticed a sewage smell coming from the lower level bathroom (half bath). After reviewing the posts in DIY, I replaced the sink and drain and replaced the toilet seal. I also checked the roof vent for any obstructions.

This seemed to take care of the problem until now where the smell has returned.

I poured water into the all of the traps in the house but still no luck.

The house is a 30 year old, split level ranch, with city sewer. The bathroom is on the lower level (concrete slab). There has been no major rainstorms.
I'm going to check the crawl space today.

I'm out of ideas and ready to call a professional, possibly a plumber or drain specialist like roto rooter.

Any thoughts would be appreciated.

If you aren't experiencing any back ups, the drain is probably doing its job. I know you said you poured water in all your drains, and I am only mentioning this, because I find customers fail to think of this. Is there a washing machine stand pipe in the basement? Did you pour water down it? If is it abandoned, you can pour a couple of cups of propylene glycol in it for long term trap fill. The propylene glycol won't evaporate as fast as water.

There is a washing machine stand pipe and I haven't poured water down it. I would think the regular use of the washer would keep the trap in water.

However I will give it a try.

Thanks,

Are you certain there are no breaks/bad gaskets, etc. in any of the traps where the drain water might instead be leaking out of the trap and just going into dirt/crawlspace?

And have you gotten on your knees and bent down and smelled where the toilet bowl and floor meet?

And have you checked to make sure a vent is not plugged on the roof, as if this happens this can cause sewer gas to come out an ill-fitting wax seal at the base of the toilet. This very scenario happened this winter at a commercial business and the blocked roof vent (ice) caused back-up gases to force out under the bowl of the toilet. VERY strong odor.

"I replaced the sink and drain and replaced the toilet seal. I also checked the roof vent for any obstructions.

This seemed to take care of the problem until now where the smell has returned."

Well, sink and drain are still good. Drain and trap properly installed?

Toilet seal? Hmm. Properly installed? What kind? Wax ring or one with hub? Floor flat? Loose bolts? Any movement or rocking of toilet that could have caused breakage of seal?

Roof vent? Hmm? Did the check the correct one? Does it have its own individual vent? How did you check it? Have you checked it again?

Regular use of washer should keep water in trap. Any floor drains that could have gone dry? Any sinks, tubs/showers/toilets or other plumbing in rooms or areas that are used infrequently and traps could be dry?

"I'm out of ideas and ready to call a professional, possibly a plumber or drain specialist like roto rooter." Go through the whole process of elimination again before calling in the expensive option. And, perhaps someone else on our team will have more suggestions.

Do you have a basement drain pipe (say near the water heater)? Make sure you put water down that as well. We had a similar problem and the basement drain pipe was the culprit.

Yep, I poured water down that as well. I'm going to check the crawl space this weekend and the vent stack on the roof this weekend.

Not sure who to call professionally. My plumber told me they don't investigate sewage odors. :-(

Your plumber doesn't investigate sewer odors? Interesting. Try all u can first as others suggested..but if you feel the need just try another plumber. Plumbers DO investigate sewer odors..at least where i live that is part of our job. Never heard of one that didn't.