Bad Smell/Sewer Gas? Coming From Closet

Old 03-02-18, 09:44 AM
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Bad Smell/Sewer Gas? Coming From Closet

I live in a ranch/concrete slab style house outside of Chicago, built in the 1950s, but with some renovations since. We have well water, but are tied into the city sewer system if any of that matters.

I've noticed a faint smell that has been getting worse, and after removing everything else, I'm convinced it's coming from this PVC pipe/opening in the floor.

I'm able to easily unscrew the top (there doesn't appear to be any rubber seal or anything that would make an air-tight fit

When I remove the top, I can see that the pipe goes down a bit, and connects to another pipe down below. There is visible water but it looks nice and clean. With it open, I can confirm that it is the source of the smell.

My question is....what do I do to fix this? My first thought is to just make the seal airtight....cover it with something? But I figure there is a 'correct' way to do it and whatever I do won't be correct unless I get some advice from people who know. Can I just caulk the thing shut?

Thank you

EDIT - also if anyone can tell me why my images are blocked out/not rendering I'll fix em
Old 03-02-18, 10:52 AM
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Your pictures are being hosted at a site that DIY doesn't allow.

You can post your pictures directly to the board... How-to-insert-pictures
Old 03-02-18, 12:06 PM
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One quick thing to try is to liberally smear Vaseline over the threads of the cap and screw it back in. The Vaseline will help form an air tight seal. If the smell goes away then I'd tighten the cap down properly. Many plumbing fittings have a tapered thread. When tightened down properly they are water and gas tight. But, if only done hand tight they can let gas escape.
Old 03-02-18, 07:03 PM
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Possibly a dry trap....

If that is possible, just pour some bleach and water in it at first, and then follow up with a few cup of water every few weeks. If this only started happening recently, maybe it is because you changed some habit in the house and are no longer using some fixture that was keeping the trap wet.

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