My house is a renovation of a 1940 house. Many of the old nonworking disconnected parts were left in during the reconnection, including this 5 or 6" cast iron drain pipe. I recently noticed that the area where this pipe is found (which is in the basement) smells like a cat's litter box. So it could be the result of dampness, or one of my cats took a pee there or - and this is my question - could it be that this pipe is somehow connected to my plumbing elsewhere in the house and that sewer gases are escaping through it. To me this scenario seems highly unlikely. On the other hand, why would they not cut it out and instead cut the plywood around it?

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  • 1
    I think the only way to get an answer is going to be to have someone look at it on site. Too much detail needed. I'd be tempted to try something silly like pointing a thermal camera at it, running hot water, and seeing if it warms up at all, though that would be a minor effect and probably hard to measure. (My house inspector told me he stopped trying to guess at odd plumbing's intent after what looked like an unexpected drain pipe turned out to be the previous homeowner's safe.)
    – keshlam
    Nov 16, 2022 at 7:41
  • @keshlam Sounds like a neat idea. Not many people would look or put their hands in what looks like a drain/waste pipe.
    – crip659
    Nov 16, 2022 at 11:54
  • Please not that the pipe is cut off within the picture.
    – Wynne
    Nov 16, 2022 at 12:59
  • What's behind the paneling? Is that the foundation wall and this pipe runs directly out from under the house? If so, it's possible that it's still connected to the sewer system somewhere. It's possible that it's disconnected, but that it collapsed somewhere outside the house and that a critter has made a nest in it. You're going to need to look in the pipe with a camera to see what's down there. You can rent one or have a plumber come out and look down there - he'll have more experience to ID what he sees, but you could have a look first.
    – FreeMan
    Nov 16, 2022 at 13:55
  • @Wynne: Not cutoff, just goes into the concrete. I have some of that in my own basement. Which, FWIW, is indeed still connected and in use.
    – keshlam
    Nov 16, 2022 at 23:13

2 Answers 2


Since your question is in regards to the source of an odor, I'd suggest the following. To see if it's still active (or the source of your odor), take a sturdy plastic bag, stick it over the end, and use some rubber bands to hold it in place and seal the opening. Then see if the odor remains after couple days. If the odor disappears, that was the source and you can proceed as appropriate to remediate that. If the odor remains, you know the source is elsewhere.


Come at this from the cat angle.

If you are asking yourself - "did my cat pee here?" most of the time the answer is yes. It is part of their charm. You could check the area with a black light aka ultraviolet light.

cat pee


Re interesting old pipe: rubber band a plastic bag around the end. If bag blows off air is coming thru pipe. If bag sucks in air is leaving thru pipe. All fascinating. Then replace bag with wad of rag because rubber band and plastic will deteriorate with time.

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    So, peeing everywhere is "Charming", eh?
    – FreeMan
    Nov 16, 2022 at 18:27

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