New build that's almost 3 years old.  Never had issues with flys till 2 months ago.  Then its like someone gave them a key to the front door and they let all their friends in.  Most are in the kitchen area but there is always 1 or 2 somewhere else in the house.   A good example is I bought a few of those sticky long fly trap things that you hang.  I put 1 in the kitchen above the stove *we rarely use the stove anyway* and 1 in the hallway.  The kitchen will get between 6-8 flys a day.  The hallway....maybe 1.  Which tells my the source is SOMETHING in the kitchen.   Wife and I have literally pulled everything out of the cabinets, pantry, drawers,  ect and cleaned it top to bottom.  Trash gets taken out every 2-3 days even if it's not full and I cover the sink/garbage disposal hole.  Still...  doesn't matter and I'll still get 6-8 flys on the fly trap.  

I guess I should add, we are not messy people.  House always looks clean and I usually spend 30 mins a day just picking up or wiping down stuff.  Food isn't left out and there are not odd smells anywhere.  I've even checked the vents and don't see anything. I'm at my witts end.  Anyone have any other ideas?

You might be better served looking for the entry point, I had a bad fly problem one year from letting teh dogs in and out all day long.
Found a parasitic wasp that preyed on flys and it really cut down on them, they lay an egg on the maggot and eat it, wasps themselves are tiny, gnat sized.

I thought it could be that too, but I'm down to just the 1 dog.  She's older and only goes out twice a day.  That being said, I also cleaned all around the back patio and did the whole waving arms thing as I'd open and close the door to let her out.  I never recall seeing flys make it in but it's possible.

Houseflies, fruitflies, horseflies?

We have a couple of stinky fly traps about 30 feet from the back door and they have helped a ton.

Just regular house house fly.   I'll try 1 of the traps right outside the back door and see what happens.  Thanks.

Checked the fly trap outside by the door and 0 flys.  

Checked the fly trap in the kitchen this morning and probably another 4-5 flys on it.  

The 1 in the hallway...1.  

So it's still telling me it's something in the kitchen.  I guess I'll just have to go through the kitchen again, clean everything, and see what I find.  Or don't find.

Are you sure they are houseflies and not cluster flies?

I had to Google wtf a cluster fly was

Yeah, these definitely arent cluster flys.  Looks like the normal house fly.  Plus it's not THAT many of them.  I'll admit, ever since I put up the fly traps, the # of them just randomly flying around has dropped to almost 0.  Infact 1 was flying around when I replaced the old 1 in the kitchen with a new 1.  I came back to get something out of the kitchen a few minutes later and saw it already found the trap.  I'm going to get a ladder and check the vents this weekend.

My house was absolutely infested with cluster flies when we moved in. 2 years of treatment wipe them out. The reason I asked is they don't usually enter through the doors. They enter through other gaps, just looking for a warm place to sleep for the night (or the entire winter) and it's inevitable that of the tens of thousands in the walls and attic, a few find their way in through a lighting fixture etc.

FWIW, the only way I can tell a cluster fly from a house fly is it's behavior. They look very similar and I can't get my magnifying glass close enough to see the subtle differences without them flying away...

Sure glad I don't have to deal with them anymore though. I still have some, but it used to be swarms of them in early spring and fall. They would be outside sunning themselves on every single surface that the sun was hitting.

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PT Alpine Pressurized Fly Bait - 16 oz can - by BASF Brand: Alpine 4.6 4.6 out of 5 stars    4,043 ratings

Here I have not just flys but also gnats, and it sucks to mow the lawn with the gnats trying to get in your face.. Same with the flies..  

So I got one of those foggers/blowers that literally throws insecticide around the trees and side of the house..   No more bugs, and I am really surprised at the knockdown power of those things..  It was bug free in less than 30 minutes..  Of course if you have dirty neighbors, then the flies will come back since they are close...     (spray on their side of the fence, so the insecticide will kill them as they land on the fence)


You are doing good with indoor traps..  Trap the ones you can and that is most of the battle..Kill anything outside so it can't come in.

We built a house 18 months ago and this was our second summer.  Last summer, our first, we kept getting tons of flies daily and couldn't figure it out at first.  They were in our attic, hundreds of them.  Our house is fully sealed with spray foam.  No idea how they got in, if they someone got in during the build and bred during the winter.  That was our source.

Bug bombed the attic and killed them all.  Not a single issue this year.

Very strange, but that is where ours were.

OP, curious, is your house attached to your garage, and do you store your trashcans in your garage?