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TJ22 04-24-2014 08:31 AM

Open pvc pipe in basement ceiling
Off and on I was having a sewage smell in the basement. Last time it happened I tracked the smell to a open pvc pipe sticking down from the ceiling. Not home currently but I think it was like 1 1/2 - 2" in diameter. I cannot easily trace it but I am assuming it is connected to the plumbing ventilation. Is this normal? I do have an older gas furnace I thought maybe it was to pull air in but it is very far from the furnace. I put some duct tape over it and the smell stopped. Can I permanently cap it off?

nealtw 04-24-2014 08:53 AM

That sounds like a mistake, put a cap on it.

bud16415 04-24-2014 08:54 AM

When water flows down a pipe it needs air behind it or the vacuum caused will slow the water and pull water from traps and drains along with it. You will hear “clugging” from other drains when a vent is blocked. If smell is coming from it and water isn’t it sounds to me like a vent not done properly. It should exit the house at minimum. Most of the time people don’t want sewer gas coming out low on the house and getting sucked in windows and this is why you see vents going up and thru the roof.

JoeD 04-24-2014 09:48 AM

Plug it with something and see what happens. Could be a left over vent line from a removed or not yet installed sink in the basement.

bud16415 04-24-2014 10:21 AM

If it’s sticking down from the ceiling in the basement I would suspect its venting something on the first floor. I would figure out where that point is on the first floor and go up there and take a look. Maybe a bathroom or kitchen is above that location. If the pipe is located in a wall it gets a little trickier but I doubt a plumber running vents in a wall would opt to go down and just stop there. Clearly smell is coming out it so it is connected to a live line.

We could guess as to what’s above, but the OP can take a look and let us know easier. Capping it off might work or it might seem to work until someone runs a sink or two and flushes a toilet all at once and then a trap will get sucked dry and there will be a new location for a smell. There are a many things it could be maybe someone installed a cheater vent and ran the air inlet down and now the cheater is stuck. We just don’t know the facts beyond it’s an open pipe and sewer gas is coming out of it.

nealtw 04-24-2014 10:32 AM

Bud Either way, this has to by capped. If there is another problem there will have to be another solution to that problem.

bud16415 04-24-2014 10:37 AM

Cap it or extend it outside.

CallMeVilla 04-24-2014 08:26 PM

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I say cap it temporarily then test drains upstairs. If they run slowly, that might be the culprit ... and you DO need a vent. If you cannot re-route it easily, then the only option I can suggest might be an air admittance valve. (see pic and link)

The difficulty is I believe AAVs need to be mounted vertically, not upside down. They certainly cannot be mounted on an angle. The manufacturer can explain this ...

TJ22 04-28-2014 09:53 PM

Thanks for all the info. I apologize for the delay. Since taping it off I have not been having the issue so it slipped my mind. I will take a look and se if I can figure out where it goes. It's near a bathroom above but maybe it is a vent for future basement plumbing. I hadn't thought about that.

kok328 04-29-2014 08:56 AM

Future plumbing would have been already capped off. Perhaps there used to be a bathroom down there and was removed? Maybe a exhaust pipe for a radon removal system that is no longer there?

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