This page contains affiliate links. If you make a purchase after clicking a link I may get a commission at no cost to you.
It’s deeply distressing when a swarm of flies appears in the house. We all associate flies with filth; after all, we’re used to seeing them around trash heaps, manure, and carrion. What’s worse is that, if the flies are there long enough, you’ll find maggots, too. There are many reasons why you might suddenly find a bunch of flies in your house, and, fortunately, there are several easy ways to get rid of them.
Why are there so many flies in my house all of a sudden? 5 reasons
1. Something’s rotten
Flies need rotting organic material to reproduce, they lay their eggs in it and their larvae (maggots) need it to feed on. You’d be surprised at how little they need, too. A few food scraps left in the trash can too long, or going too long without running the garbage disposal, can be all it takes.
In fact, if there are a lot of flies in your house, it’s pretty much a guarantee that there’s some rotting food somewhere in the house. A small number of flies laid their eggs in it, and they all hatched at once, which means they all matured into adult flies at once.
The result is a swarm of flies appearing all at once, with no warning. It’s certainly alarming, but it doesn’t mean your house is filthy, they can breed in truly tiny amounts of rotting matter, and even the cleanest home can develop a fly problem.
Naturally, you’ll want to clean your house thoroughly once you’ve discovered flies, but you still need to deal with the flies that are in your house before they have a chance to breed. One good way to get rid of them is with a bug zapper. These may seem old-fashioned, but they work remarkably well.
This zapper includes a scent attractant in addition to the light. It makes it irresistible to flies, mosquitoes and fruit flies. It’ll clear up your problem in no time. We’ve been using this same one for weeks now and it has certainly helped.
2. Your house isn’t sealed up tight
Flies don’t just appear from nowhere. The flies in your house may have hatched inside your home, but their parents had to come from somewhere. Whether it’s the seal around a window or a door, or somewhere in the walls or the roof, there’s a gap that they got through. While it’s a good idea to try to seal it up, flies can get through tiny spaces that may be hard to find.
It won’t do you much good to get rid of the flies that are already inside your house if more flies are able to get in and lay their eggs. So, you need to prevent the flies from getting in. It’s possible that every door and window is perfectly sealed, and flies get in anyway. Every time you open a door or the window, that’s an opportunity for flies (and other bugs) to get in your house.
Obviously, leaving doors and windows open for a long time is even worse, but any time their opened a fly or two could get in. And, of course, you can’t avoid opening them, either. So, what can you do?
You could hang the bug zapper we recommended to you outside, it’s suited to both indoor and outdoor use. But you could also use traps like these. They’re non-toxic, highly effective, and don’t require batteries. Just hang them up near your doors and windows and watch them fill with flies, gnats, and mosquitos. These traps work well, too.
Also consider some new weather stripping or even some magnetic screen doors to help seal up your home.
3. Your house needs to be cleaned
Flies can breed in tiny amounts of filth, but a tiny amount of filth is still filth. If you want to fix your fly problem, you need to figure out where they’re breeding and clean it up. Odds are that it’s something you haven’t noticed, and it could even be something small and hard to see.
That means it may take some effort to find the spot you need to clean. One good way to do this is to lay out glue traps. Place near likely places for food debris like the garbage disposal, the trash can, and any place your or your family likes to eat.
After a few hours come back and check the traps. The trap with the most flies in it is likely the one closest to where they’re feeding and breeding. That should help you figure out where the problem is. In addition to removing whatever the flies are feeding and breeding in, be sure to check back in a few days.
This time, you’re looking for maggots, or fly larvae. You may have removed the food they were going to eat, but once they’ve hatched they can definitely find more food, so you want to get rid of them as soon as possible. Just grab a vacuum and and clean them up. Be sure to dump the vacuum bag out immediately, though, or you’ll end up with a vacuum full of flies.
4. Your yard needs to be cleaned
In addition to keeping the house clean, you want to keep your yard as clean as possible. if there are fewer flies outside the house, there’s less of a chance that flies will get into the house. Make sure you’re picking up all the dog waste in the back yard.
You might be surprised by how much of a difference this can make in the size of the fly population. Especially if you’ve noticed an unusual amount of flies out in the yard, picking up all of the dog poop can make a huge and immediate difference.
5. You didn’t kill all the flies last time
Flies breed fast. If you don’t get rid of every fly in the house, there’s a very good chance they’ll lay more eggs and, in a few days, your fly problem will return. You’ll need to be thorough. Set up the bug zapper, the traps, and get out the fly swatter.
Of course, none of these is guaranteed to get every single fly. You’re going to have to go hunting. A fly swatter is a great tool, but it has it’s limits. First, it’s actually pretty hard to hit a housefly with one. Flies are fast and they can see you coming from almost any direction. Second, if you actually hit one, your left with a smear of pureed fly on the wall.
Finally, a fly swatter can only hit the flies you can reach. And flies can, well, fly. They can get out of reach easily. You need to try the Bug-a-Salt. At first glance it seems like a novelty item, but it’s actually a very practical way for killing the flies and other bugs you can’t reach.
It works better than a fly swatter, because the fly can’t see it coming. And it can easily hit flies that are far out of your reach. Just add the salt to the hopper and get hunting. If they’re old enough you can even get the kids involved and put bounties on the flies!
