Hey everyone,
I woke up this morning to find several large black flies buzzing around my kitchen and living room. 
I haven’t left any food out, and the windows and doors have mostly been closed, so I have no idea how they got in.
Has anyone experienced this before?
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Could they be coming from drains or vents?
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Is this a sign that something died in the walls or attic?
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How do you find and stop the source before it turns into a full-blown problem?
Would really appreciate any insight or similar experiences.
Hey @HouseHelp101! That happened to me once right after my garbage disposal broke. Turned out some organic matter got stuck inside and became a breeding spot. Check your drains, especially in the kitchen and bathroom.
If they’re slow and kind of noisy when flying, they might be cluster flies. They usually sneak in through tiny gaps and tend to show up in warm weather. They’re annoying but harmless.
You might want to check the attic or crawlspace. I found a dead mouse up there once and that’s exactly when the flies appeared. Once I cleaned it out, the problem disappeared within a day.
Sometimes they come from indoor plants if the soil stays damp for too long. I’d move the pots outside for a bit and let the soil dry before bringing them back in.
Good idea to check windowsills and vents too. Flies love sneaking in through loose screens or tiny openings around air ducts. A quick reseal or screen patch worked for me.
I had this exact problem last summer. It started with just a few flies, then I realized they were coming from the recycling bin under the sink. Even small residue from bottles can attract them.
If they’re appearing all of a sudden, there’s usually a food or moisture source somewhere nearby. Clean behind the fridge, under the stove, basically all those forgotten spots. You’d be surprised what turns up.
They might be coming up from basement drains. I pour hot water down mine once a week just to keep things clear. Works well and keeps smells away too.
I’ve noticed these flies often show up when it gets humid. Dehumidifying the space or keeping windows open for airflow helped a lot in my case.
Once you track down the source, they’re easy to get rid of. I just kept things clean, dried out damp areas, and after a few days, no more flies anywhere.