Hey everyone,
Over the past couple of days I’ve noticed several large black flies showing up inside my house, mostly near windows and the kitchen. I don’t usually deal with flies indoors, so this feels sudden and a bit concerning.
I’m trying to figure out what might be going on and where to start. A few things I’m wondering about:
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Are large black flies usually a sign of something dead or rotting nearby?
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Could they be coming from drains, walls, or attic spaces?
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Is this something that typically resolves on its own, or does it need action?
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At what point should I consider calling a professional?
Would love to hear if anyone’s dealt with this before and what actually helped.
Large black flies usually mean there’s a food source somewhere. In my case it was a forgotten trash bag in the garage that I didn’t connect at first.
Check your drains too. I had flies coming from a floor drain that barely got used. A deep clean solved most of it.
If they’re clustering around windows, they may already be inside and trying to get back out. Still worth checking for where they came from though.
Seasonal changes can trigger this. When it warmed up suddenly here, flies started emerging that must’ve been dormant.
@NatureLover23 Do you have pets or any chance something got into a wall or crawl space? That’s what caused my fly problem last year.
I wouldn’t panic, but I wouldn’t ignore it either. Flies multiply fast if there’s a breeding source nearby.
Avoid spraying randomly until you know the source. Killing adults helps short term, but it doesn’t stop new ones from appearing.
@UrbanGardener99 Seconding the drain advice. Boiling water + enzyme cleaner worked better than chemicals for me.
If the flies are big and slow, they’re often house flies, not something exotic. Still annoying, but usually fixable with cleanup and sealing.
@RatHunter92 Same here. A small dead rodent in the wall caused weeks of flies. Once it was removed, the problem stopped completely.