They look like drain flies.... help!

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Old 06-30-17, 10:39 AM
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They look like drain flies.... help!

I used a bacteria waste eliminator. The microbes eat the waste that clogs drains and septics. Bacteria culture, amylase, protease, cellulase and lipase enzymes attack grease, decaying organic matter, etc.

Started noticing the flies in my daughters bathroom. They'd work their way into the hallway, but seemed to originate in bathroom. Cleaned her sink drain with brushes, etc. and the same for shower drain. Then used the bio-clean. No more drain flies.

Except...

They swarm in my attic. Cannot figure this out. They certainly like windows, but I don't have any moist, rotting organic matter for them to hatch and thrive on outside. This all started after we did some work on our house in early winter 2016. This included some plumbing work. Over the winter, the attic smelled funny, almost gassy. That smell is gone, but the cute little drain flies returned.

I can't see anything that vents INTO the attic. Only vents to the outside: system vent, and two dehumidifier vents that seem well sealed.

HELP!!!!
 
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Old 06-30-17, 11:06 AM
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I started a new thread for us.

Are you positive that they are what is commonly called a “drain” fly or “sewer” fly?The specific name is “psychoda”. Do a search and see what you think. If you can’t be sure what they are, then a positive ID from an entomologist or county agricultural extension agent would give us a positive ID which would point us in the proper direction as to their breeding habits, preferred locations, food sources, etc. With flies, both large and small, their habits differ so much that it really is important to know specifically what we are dealing with.

The behavior you describe does sound like the “drain” flies or psychoda. If so, then there is decomposing organic matter somewhere otherwise they wouldn’t exist. Attics typically aren’t where we find these guys, though.

Is the attic open across the top of the living spaces? Private septic or public sewer? If they are psychoda then I suspect a drain venting issue somewhere.
 
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Old 06-30-17, 02:20 PM
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I am positive they are drain flies...flying pattern, basically made of dust, cleaned out the drain in daughter's sink and found the clear-ish goop they nest in... they're "psychos" all right. We have a private septic. The attic is not open across living spaces. Please ask me whatever you need; I am determined. I was about to order Rid-X to treat the septic, but remembered there's no way they can to get into the attic. I may just try it anyway...can't hurt. They're not appearing anywhere else in the house.
 
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Old 06-30-17, 02:52 PM
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The vent lines don't vent into the attic..... they pass thru the attic and vent out thru the roof.

However..... the vent line may have become disconnected or has a hole in it.
That may have occurred in the wall where it can't be seen.
 
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Old 06-30-17, 03:10 PM
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I understand that they vent through... that's the mystery. It's like a high school reunion in my attic, but I don't know how everyone got there. Today I contacted the plumber who did the work to see if he had ideas. No response yet. Suggestions as to how to narrow down the location of the leak? Or, just use a product to address the septic system? I treated the bathroom drains with bio-clean, the kitchen sink, I don't think I missed anything. Thanks for all the quick replies.
 
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Old 06-30-17, 03:20 PM
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Yes.... let us know what work he did.

I'm not sure the pests would be in the septic itself but I would think they could be living off the sludge on the plumbing in the walls.

Finding that leak is a little out of my expertise but if it was me I'd be sending smoke down the vent line to see where it came out.
 
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Old 06-30-17, 03:23 PM
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I also started cleaning the attic today. Not finished yet, but maybe when done I can look for patterns of where they come from....
 
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Old 07-01-17, 08:00 AM
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Getting up there and cleaning/investigating is a good step. Even when one doesn’t know exactly what they are looking for, the very act of being up there may provide a clue.

I too suspect a separated/broken vent line that may look intact but isn’t. Since the attic doesn’t go overtop of the entire house, is it possible that some plumbing vent lines are not visible?

I doubt that Rid-x will help if there is a venting compromise.
 
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Old 07-01-17, 09:19 AM
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Dehumidifier vent

First, I misunderstood your question about the attic being open across the top of the whole house. Yes, the attic runs the length and width.

I disconnected the vent line from the bathroom vent. My thinking was that maybe drain flies, which disappeared from every place besides the attic, may have been going up into the bathroom vent. If there was any water or organic matter accumulated in there they might have thrived.

Ugh. I just need to look INTO the vent box in the attic.

Comments? Thoughts?

Thanks again all.
 
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Old 07-01-17, 10:33 AM
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The work the plumber did: Installed a new bathroom including a walking shower and two sinks and toilet. Installed an entry to the wastepipe in the basement for the discharge hose of a Catgenie (ha!) . Installed plumbing for relocated washer and dryer in mudroom and new half bath in mudroom with sink and toilet. I think that's it...

Still no word from him. He's good about getting back to me so we'll see...
 
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Old 07-02-17, 07:48 AM
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The “vent” lines that we are talking about are not the exhaust fan or air ducts/vents.. The plumbing vent lines/pipes are made of the same material, usually white pvc, that the sewage pipes/drain pipes are made of. They don’t carry the actual waste but they do penetrate through the roof to provide venting so that when a toilet is flushed or sink full of water goes down the drain, that the waste water is not pulling against a minor vacuum. These lines/pipes are directly connected to the sewage pipes so that is why flies would use them to enter living spaces in the event of breaks/separations/etc.

I wanted to make sure that we are all on the same page when we say “vent”. That term can mean different things to different people.

What is the “vent box” that you referred to?

Find every roof penetration in the attic and move the insulation around it or reach through and use you hands, bare skin, to feel for dampness on or around the base of the vent pipe. Inspect everything that is involved with the vent/sewer pipes and inspect all of it. If/when you get close to the source you will see much more activity as you disrupt them. This is the physically unpleasant part of the job but someone has to do it.
 
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Old 07-02-17, 10:21 AM
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Awesome. Thanks. Yes, I felt we needed to get on the same page with "vent". I've been doing that with the insulation... I will follow and get back. Attic is uninsulated and since my daughter sleeps until 9 right below it's creaky floors I can really on work on it when sun has gone down.
 
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Old 07-26-17, 06:11 AM
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Update:
Cleaned the attic, and it's now free of the stupid drain fly corpses. I also detached the vent hose from my daughter's bathroom fan, both of which, I think I mentioned, are in the attic. I didn't see ANY live flies while I was cleaning. Granted, we have left the 2 attic windows about 2" open for hot air ventilation and to let the remaining flies leave, but that was before I started cleaning. So, while they MIGHT be proliferating, my guess is that they were growing inside the fan. The attic heat has been circulating around the exposed fan opening so maybe it dried any fly nests? We'll find out. Since cleaning, I haven't seen ANY flies up there. As we know, they have very short flight spurts. The fan is in the center of the attic, about 20 feet from each window. They used to come down the stairs, too, and not just out the windows. None appear between the fan and windows, or anywhere else. Zippo. Keeping my fingers crossed.
 
 

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