Intermittent, unexplained odor in house

Who's in the room when you smell it?    Is it all over the house or mainly in one area?

I know for us - our house had a chain smoker and there's one area we didn't paint (closet area under the basement stairs) - when it's super humid - sometimes we smell it.

@jeffl  jamie’s question is a good first one.  Try to isolate its source and any pattern like day vs night, hottest day(s)?, is it only indoors….   How long has this been going on?   Have yu checked the attic?

Any pattern to the way the wind is blowing when there is an odor? (Something outdoors like mulch? Something in the walls/windows/attic/crawl space like mold?)

Maybe you can’t explain it, but can you at least describe it? So far it’s obvious that the smell is 
PSEG…. Gas-possibly 

Plumber…sewerage -possibly 

Pest control agent….cadaverine-possibly 

Could be wafting over from a neighbor’s yard…

Do you have carpets that came with the house, and did previous owner have a pet? Even cleaned carpets can retain a urine smell and release it on a humid day. And/or if they had an intact male cat that marked, the odor might come out on a damp day even if everything was thoroughly cleaned, painted, etc.

Environmental cause from outside the house is another possibility, especially since the odor is intermittent.  Even with windows closed, I sometimes smelled the smoke from the Canadian wildfires last week.  Mulch/manure odors can also waft into the house, especially after a heavy rain. 

Without knowing if others in your house notice it, and time course of the odor being evident:

Olfactory aura - temporal lobe seizure.

Wow!   Thanks for all the suggestions.  I don’t think it’s temporal lobe seizure. No smokers.  No farters. It is definitely in the basement and first floor, not the second floor.  Sometimes even on our deck.  

We’ve detected no pattern for when I happens.  We have definitely ruled out gas.  The pest control guy said dead animals and sewage have similar smells but he checked all around the house, inside and out.  He couldn’t check the eaves. 

Would a dead animal’s smell come and go over the course of a couple months?

Would a sewage smell come and go?  Maybe I get the main drain rootered just to be sure?  No water backs up anywhere in the basement.  

A sewage smell can come and go if the water in any of your p traps has evaporated.  If your washing machine drain hose extends too far down into the drain pipe it can suck water out of the trap when the pump shuts off.  Is there a waste vent pipe through your roof anywhere near your deck?

Something else just occurred to me. We were getting an intermittent sewage-y smell in our basement and my husband was worried about a leak in the air stack, or something like that. I noticed that our low flow toilet in the basement (that we don't use that often) didn't flush all the way and wondered if that was the cause. We started making sure we chose the full flush when we use it, and no more smell. I know you had a plumber in but am not sure if a plumber would necessarily have thought of that. Just worth mentioning I think.

The washing machine drain pipe only goes 4-5 inches into the drain.  The Waste vent pipe is two floors and probably 20 feet away from my deck.

DanDietrich said:

A sewage smell can come and go if the water in any of your p traps has evaporated.  If your washing machine drain hose extends too far down into the drain pipe it can suck water out of the trap when the pump shuts off.  Is there a waste vent pipe through your roof anywhere near your deck?

A third visit from PSE&G determined it was gas.   After a second visit from a plumber. Now to find where the leak is!

We had a similar experience. The gas was coming out of a gas vent outside the house.  Had to have a new regulator installed. 

Argh!   Gas turned off.  Plumber was supposed to pressure test the system after opening up the walls and ceiling.  Still smells like gas!

Jeff have you asked the fire department if they can assist in determining the source of your presumed gas leak with detectors they have?  I know on routine calls fire dept. here arrives with a wide range detection capability.

Any news/updates about the pong?

marksierra said:

Any news/updates about the pong?

the pong?  Yes.  It was a gas leak.  Interestingly, I think it coincides w the water company changing our water pipe.  They tried to snake the pipe out but couldn't.  They ended up trenching my yard and shaking the foundation of the house.  My gas piping has leaks at several joints.  Coincidence?  

jeffl said:

the pong?  Yes.  It was a gas leak.  Interestingly, I think it coincides w the water company changing our water pipe.  They tried to snake the pipe out but couldn't.  They ended up trenching my yard and shaking the foundation of the house.  My gas piping has leaks at several joints.  Coincidence?  

You may want to report this "coincidence" to NJAW, Montana, and the town.  Others may be experiencing a similar issue and be unaware of the cause.  it would also help with evaluation of service line replacement program and could save others from having this problem.

joan_crystal said:

jeffl said:

the pong?  Yes.  It was a gas leak.  Interestingly, I think it coincides w the water company changing our water pipe.  They tried to snake the pipe out but couldn't.  They ended up trenching my yard and shaking the foundation of the house.  My gas piping has leaks at several joints.  Coincidence?  

You may want to report this "coincidence" to NJAW, Montana, and the town.  Others may be experiencing a similar issue and be unaware of the cause.  it would also help with evaluation of service line replacement program and could save others from having this problem.

Good idea, Joan. 

Jeff: What method was used to determine the precise sites of leakage, and who identified them? Were they close to where the gas line enters the interior of the house or more distant from that point?

“Several joints” certainly sounds like secondary to widespread physical trauma - c/w foundation shaking as the etiology. 

dickf3 said:

“Several joints” certainly sounds like secondary to widespread physical trauma - c/w foundation shaking as the etiology. 

Today’s update. The gas leak is back and neither the plumber nor PSE&G have a clue where it’s coming from. No one can explain why the odor can go away for a week and then return with a vengeance. The plumber pressure tested the line after it was repaired and found no leaks. Three days later, the smell was as bad as ever, and the gas is off again.  PSE&G decided they’re going to rebuilt the entire service into the house to eliminate that possibility.   Argh!!!

jeffl said:

Today’s update. The gas leak is back and neither the plumber nor PSE&G have a clue where it’s coming from. No one can explain why the odor can go away for a week and then return with a vengeance. The plumber pressure tested the line after it was repaired and found no leaks. Three days later, the smell was as bad as ever, and the gas is off again.  PSE&G decided they’re going to rebuilt the entire service into the house to eliminate that possibility.   Argh!!!

Could be more than just your house-side line that was impacted.  Has anyone checked to see if there are additional leaks coming from the street side?   It is good that PSE&G is taking this seriously.  Unfortunately, it must be very stressful for you.  Please let us know when the situation is fully resolved.  

When the regulator was malfunctioning at our house and gas was coming out of the outside vent, the repair tech told us this often happens when someone gets a gas appliance replaced, and the gas is turned back on too quickly, causing the regulator to malfunction. I often smell gas when walking the dog, and wonder if it's coming out of someone's gas vent. I think it is fairly common, since it has happened to us twice. (One of those times was when the gas company replaced our meter!)

RichardR said:

We had a similar experience. The gas was coming out of a gas vent outside the house.  Had to have a new regulator installed. 

Could it possibly be coming from the neighbor’s gas meter, or incoming gas line from the street? 
It’s costing you money to identify the source of the leak, what if it’s coming from a neighbor? 
Years ago there was a strong odor of gas coming from the street at the corner of Springfield and Tuscan, right in front of Wyman Ford. 

PSE&G has now replaced the service inside the house and capped an old water pipe that was never capped.  They said that gas could have been coming through there.  I won’t feel like it’s fixed until we’ve had a couple weeks of no smell.  

I never had an issue relating to gas odors, but several years back when they replaced our gas meter I asked the installer about my impression that for some time the gas pressure feeding my stove was different -- perhaps too low. When he tested the pressure he agreed that it was too low, Indeed, almost nonexistent,  and reported it for further investigation. They determined that was a leak (or leaks?) in the pipe leading to the house and sent out a team that lined the pipe leading to the house with something that in my layman terms resembled a hose. The process included digging two four or five foot deep holes on both sides of the street. It worked!  

PSEG takes gas leaks seriously so they'll keep investigating until they find out the source of the odor.

Yeah, we have that plastic sheathing already.  They are taking it seriously and maybe they found the issue today.  Time will tell.  

krnl said:

I never had an issue relating to gas odors, but several years back when they replaced our gas meter I asked the installer about my impression that for some time the gas pressure feeding my stove was different -- perhaps too low. When he tested the pressure he agreed that it was too low, Indeed, almost nonexistent,  and reported it for further investigation. They determined that was a leak (or leaks?) in the pipe leading to the house and sent out a team that lined the pipe leading to the house with something that in my layman terms resembled a hose. The process included digging two four or five foot deep holes on both sides of the street. It worked!  

PSEG takes gas leaks seriously so they'll keep investigating until they find out the source of the odor.

Maplewood just announced that PSE&G is going to begin addressing low pressure gas lines in sections 2 and 3.  They have already identified streets in Section 3 where they are beginning this work.  

joan_crystal said:

Maplewood just announced that PSE&G is going to begin addressing low pressure gas lines in sections 2 and 3.  They have already identified streets in Section 3 where they are beginning this work.  

Map is missing some of section 3. Is that an error or no issues on the missing parts?