Hey everyone,
I’m hoping someone can help me figure this out. Over the past few days, several large black flies have suddenly shown up inside my house. They’re bigger than fruit flies and way louder, and I can’t figure out where they’re coming from.
I’ve checked windows and doors, taken out trash, and cleaned the kitchen, but they keep appearing—mostly in the living room and near one corner of the house. I’m starting to wonder if there’s something I’m missing, like a hidden source or entry point. Any ideas on what usually causes this?
Large black flies usually mean there’s something attracting them nearby, often something decaying. Even a small source can cause a big spike.
Had this happen once and it turned out a mouse had died in the wall. Not saying that’s your case, but sudden fly appearances are often tied to something like that.
Check floor drains and rarely used sinks. Flies can come up from plumbing if there’s buildup or organic matter down there.
@MousePatrol Same experience here. We thought it was random until the smell showed up a day later. The flies always arrived first.
@CleanLivingAmy I didn’t even think about drains. I’ll check the basement sink since we never use it.
If you have pets, check hidden areas where food or treats might have rolled under furniture. That caused a mini fly explosion at my place.
Seasonal changes can trigger this too. Flies sometimes emerge indoors if they pupated earlier and temperatures shift.
@ScienceBuffBen Are they mostly near windows during the day? That usually means they’re already inside and trying to escape, not coming in fresh.
The key is finding the source, not just killing the flies you see. Once the source is gone, they disappear surprisingly fast.
I’d do a full check of attic, garage, and wall-adjacent areas. Flies showing up all at once is almost never random.