# Sweet pungent smell in basement room when opening window



## gksswein (Apr 18, 2015)

We had an addition built about five years ago. We put a full basement under the addition with a ecress window in one room. The contractor also put a round hole in the floor of one room that has a sump pump with pvc pipe going up to the outside. This pump is never used since there are never any water problems in this area. He also burid big black tubing over clay tile around the bottom of the addition before backfilling the hole. the tubing starts at a drain in the egress window pit and goes to the previously mentioned sump pump. 

Here is the problem that we have been trying to figure out now for five years.
There is no smell when the windows in the basement are shut. But if you open any window in the basement and especially the egress window, within a half hour you begin to get this strong sweet pungent odor only in the room with the sump pump whole. If i shut the window(s) the odor disapates within 15 minutes. I have put a shop vac hose(on blower) into the hole of the tubing in the egress window and smelled the air coming out the pipe in the sump pump hole and the air smells fine. Seems to have something to do with the change of pressure? Really stumped on this one. 

Thanks in advance for any ideas.


----------



## Bob Sanders (Nov 10, 2013)

Does this system your contractor installed connect to the sewer system anywhere? I ask because it sounds like you're smelling sewer gas.


----------



## gksswein (Apr 18, 2015)

*No connection to sewer lines.*

Thanks for your response Bob. 

No it does not. Although all the new plumbing for the new upstairs rooms are in this room. All pvc. 

It doesn't smell like sewer gas as in the typical smell I associate with sewer gas. 

I am trying to figure out a logical reason why it only manafests itself when a window is open. And then goes away when closed. 

Gary


----------



## Bob Sanders (Nov 10, 2013)

Is there a gas pressure regulator in the area near the window?


----------



## gksswein (Apr 18, 2015)

No. It is really wierd because the room in which the smell is, is not the room the window is in. Picking up on your first response with the sewer gas, I wonder if the plumbing vent going up to the roof from that room could have a leak at a joint and the window open creates some sort of reverse pressure. It just doesn't really smell like a typical smell you associate with sewer smell. 

Do you know if there are any type of professionals that could test anything. 

Thanks 

Gary


----------



## Bob Sanders (Nov 10, 2013)

gksswein said:


> No. It is really wierd because the room in which the smell is, is not the room the window is in. Picking up on your first response with the sewer gas, I wonder if the plumbing vent going up to the roof from that room could have a leak at a joint and the window open creates some sort of reverse pressure. It just doesn't really smell like a typical smell you associate with sewer smell.
> 
> Do you know if there are any type of professionals that could test anything.
> 
> ...


That was my first guess. Opening the window causes a slightly negative pressure in the basement which is sucking in sewer gas from an opening from the sewer system somewhere. Could be a P trap that has dried out and allowing sewer gas to get sucked in, or it could be coming from the new plumbing your contractor added.

I would look at that first anyway.


----------



## oh'mike (Sep 18, 2009)

First thing to do--look for floor drains and add water to the P-traps---this problem is common --


----------



## carpdad (Oct 11, 2010)

This is a guess only, but composting organics under the slab or from the back fill?


----------



## ron45 (Feb 25, 2014)

Why would you assume it's piping or drainage when it only smells when you open a window.?


----------



## gksswein (Apr 18, 2015)

*Sweet smell in basement*

That has always been my question. The room affected is next to the one with the window. The smell is only their when a window in the basement is open. When you close it, the smell disappears within 5 minutes. It does not really smell like what I usually would associate with sewer gas. It is a very strong smell which is hard to explain other than it is a yuk sweet smell that gets stronger the longer a window is open. We have eliminated dead animals and such because it has been going on since the addition was built over five years ago. Have eliminated paints and things stored there. The only direct connection between openning the window and the smell, is the drainage hose buried around the outside perimeter before the backfill was put in. It goes from the bottom of the egress window well to the sump pump in the affected room. I can't smell the smell coming directly out of the pump hole or the window well. The weird part is that it only smells when the window is open, thats why I have leaned towards something to do with pressure change. 

Thanks


----------



## ChuckF. (Aug 25, 2013)

There are common insecticides that have a sickly-sweet smell, those with permethrin or pyrethrin active ingredients. Did you or a pest contractor apply insecticide outside that window?


----------



## gksswein (Apr 18, 2015)

*insecticides*

No, nothing has ever been applied around the perimeter. Thanks .


----------



## jimn (Nov 13, 2010)

Of course one could keep the window closed. 😉
Does the draft flow in our out of the window when it's open?


----------



## mikegp (Jul 17, 2011)

Open the window and stick your nose near the sump pit. Do you smell it?


----------

