Please help — I have an ongoing sewer smell/fly problem in my apartment

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iHateFlies365

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Hi all,

I hope this is the right place to post this. I have had a phorid fly and sewer smell problem for a bit over two months now, and I’ve lived in this apartment for 3 months. I live on the top floor (third floor) and it is a corner unit, with no neighbor on the other side, just the staircase for the building. I live in Austin Texas and moved right after the winter storms happened (in case that context helps, not sure). As for the smell, sometimes it’s stronger than other times, but it’s definitely there. I would describe it as mildly annoying on average, to hard to focus on my work/activities at it’s worst. It’s not so bad that I’m nauseous in here, but definitely not pleasant.

For more context, I was fine for about a month with no flies or smell — and then it started happening. I’ve had pest control and maintenance check EVERYTHING for the flies (from the common spots like drains, all the way to the fridge and vents — they found nothing, and I am super clean/take out trash every few days. They are as stumped as I am). I spoke with my downstairs neighbor and they didn’t have any fly problem, so it seems isolated to my apartment only.

I mention both the flies and smell as I believe they’re linked. I tested plenty of times closing the vents for a couple days (and enduring the heat) and the flies would pretty much stop, as well as the smell would reduce (this wasn’t always the case though — sometimes I’d still smell it even with the vents closed). I put tight metal mesh in the vent openings but I’m still seeing them show up, and of course the smell is still here.

I want to mention that I use all my sinks/drains, as I know a dry P trap could be a cause. Doesn’t seem to be that though. And the smell is weirdly weakest in the bathroom, so although I’m not ruling it out I don’t think it’s a loose toilet wax ring or something like that.

As for the AC, it definitely smells stronger when I run it. I have had the coils and condensate pipe checked for mold to see if it was maybe that, but they were clear.

I read online that this could be a backed up sewer line, or a cracked vent pipe near the AC — does that sound right for my situation? Would I be the only one to smell the smell since I’m on the top floor, closest to the roof? Or if it was a vent pipe issue would my neighbors under me also smell it?

Finally, if it is a plumbing problem, could the flies be getting in this way? Somehow entering my apartment only?

Any help is super appreciated. I am at my wits’ end with the flies and this smell!
 

Twowaxhack

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Have them get up on the roof and dump a bottle of peppermint oil down the stacks for your building followed by a couple quarts of water.

If you smell peppermint inside then it’s a plumbing issue, if not then it’s some other cause.
 

iHateFlies365

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Have them get up on the roof and dump a bottle of peppermint oil down the stacks for your building followed by a couple quarts of water.

If you smell peppermint inside then it’s a plumbing issue, if not then it’s some other cause.
Will do! The maintenance guy is luckily very helpful, so I'm sure he'll be willing to help me with this. Thank you!!
 

Twowaxhack

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Maybe a water logged vent froze and broke in the attic.......now bugs and sewer gas is exiting into the attic space. Running the ac might pull the smell into your unit.

That’s just a guess......many possibilities. Keep an open mind.....
 

iHateFlies365

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Maybe a water logged vent froze and broke in the attic.......now bugs and sewer gas is exiting into the attic space. Running the ac might pull the smell into your unit.

That’s just a guess......many possibilities. Keep an open mind.....
Unfortunately it isn't the attic, as they have checked it several times and said it's all clear. (Supposedly) no bugs or vent holes up there
 

iHateFlies365

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I get this type call on occasion, often it turns out to be a dead mouse in a wall.
Right, that makes sense if this was a problem for a few weeks max, but this has been ongoing for over 2 months. If it was a dead mouse or other rodent it would have dried out by now, especially with the heat here in Texas
 

Twowaxhack

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Right, that makes sense if this was a problem for a few weeks max, but this has been ongoing for over 2 months. If it was a dead mouse or other rodent it would have dried out by now, especially with the heat here in Texas
Dead animals smell nothing like sewer gas to me.
 

Jeff Handy

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I have had clients who swore they had a natural gas leak, or sewer gas leak, and it was dead mice.
Or a squirrel in the chimney, dead bird in the bathroom vent or dryer vent.

Still more likely a crack in a vent from the bad weather, or a slow leak in a cracked drain line.
 

bartleyhs

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This building is about 6 years old and the smell started a little over a month ago, surely this would've been a problem before right?
Have you talked to the previous tenant? Do you know it wasn’t a problem before?
Do what Twowaxhack said. It sounds like that will solve the mystery.
 

iHateFlies365

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Have you talked to the previous tenant? Do you know it wasn’t a problem before?
Do what Twowaxhack said. It sounds like that will solve the mystery.
I have no contact to the previous tenant, but according to the office they said this is a new thing (of course they say that though). Again, I had about a month without any problems though so... I don't know.

I'm definitely gonna get that peppermint oil test done this week. Maintenance guy was supposed to swing by on Thursday but ended up ghosting so hopefully Monday he shows. Will keep you all posted!
 

Jeff Handy

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Make sure that anyone handling the peppermint oil has zero access inside your apartment, or even the hallway or nearby.
Roof only.
 

iHateFlies365

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I'll make sure he stays away from the apartment when he does the peppermint test. My question is about the HVAC though -- I smell it mostly when the AC is blowing. Shouldn't I test with the AC on?
 
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