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How Are Flies Getting in the House? How To Check Your Home

A house fly on a window sill with its reflection seen in the window.

Flies seem to show up out of nowhere in the home. They can be highly distracting, and very annoying, and some of them can transmit diseases, making them a health concern.

How are flies getting in the house? Flies come inside when they see light or feel a gust of air that’s warmer or cooler than the temperature outside. They enter through windows, doors, drains, and crevices. Sealing up cracks and garbage and installing screens will help keep them out.

Your home has several entry points through which flies can enter.

Let’s take a look at each one and what type of flies they attract, along with how to prevent flies from coming in.

Cracks and Holes

Flies are attracted to light and air coming from your home. At night, lights will bring flies to your windows.

Warm air coming from the house on a cold day and cool air on a warm day will also attract flies to your home.

While flies are crawling around your windows and doors, they might find little cracks and holes to crawl through.

If you have cracks around your ceiling fan or baseboards, they can come in from there as well. 

Types of Flies

Many flies will utilize cracks and holes to get inside, but the most common type you’ll see are house flies.

You might also find mosquitoes, blow flies, and gnats coming in from these spots too.


Sealing cracks is the best way to keep flies from crawling through them. You can use caulk from a hardware store to seal them up.


Drains are dark, moist, and occasionally gooey – the perfect habitat for several different flies.

If you have flies in your kitchen, the sink should be one of the first places you check. Built-up food or hair are irresistible homes for flies.

Types of Flies

Drain flies get their name because they love to hang out in bathroom sinks. They might also be found in kitchen sinks.

Kitchen sinks can also house fruit flies, gnats, and house flies.

Kitchen sinks are more likely to have flies than bathroom sinks and shower drains just because there can be more rotting material in there.


In the kitchen, use the garbage disposal frequently if you have one.

For all drains, clean them out with hot water and dish soap, a wire hook, or hot water and salt. Clean frequently to prevent flies from moving in.


Doors are a huge entryway for flies. Obviously, they can fly right over your head and into your home as you’re going in and out.

They hang around doors in search of light or more comfortable conditions, so they’re just waiting for a way to get inside.

Screen doors are also an easy way for flies to get in. Screens can break and flies will find those openings faster than you can grab your fly swatter.

Types of Flies

Any fly can make it into your house. House flies, mosquitoes, blow flies, and gnats are usually the most common pests that make their way in.

If you have a porch light by your door, whatever is flying around it will probably come in if it’s brighter inside.


Don’t leave doors open any longer than it takes for you to step in or out.

Holding the door open for several people to walk through at once might make it easier for flies to get in.

Frequently check your screen door for damage, and repair it as soon as you notice it’s broken.

Strategically placing several fly traps in the general vicinity of doorways is also a good preventative measure.

Read “Best Fly Traps to Safely Get Rid of House Flies ” to see our top recommendations and “How to Get Rid of Flies ” for a complete guide on banishing house flies.


Fruits are typically an attractant instead of an entry point, but it’s possible that you’re smuggling in tiny fly eggs you don’t even see when you bring home fruit from the grocery store, orchard, or farmers’ market. 

Types of Flies

Medflies, or the Mediterranean fruit fly, will most likely be the kind of fly you bring home with fruit.

The medfly is only found in the southern parts of the United States and in tropical areas of the world, so they may not be that common where you live.

Fruit flies may also be brought home, although it’s less likely because they prefer rotting fruit over fresh fruit and they probably won’t lay their eggs in fresh fruit. 

You can view pictures of each type of fruit fly here and learn how to best stop an infestation from occurring.


Wash your fruit as soon as you bring it home. It’s also wise to wash it and cut it open before you eat it.


This is arguably the main source of fly infestations. Flies love garbage – it smells bad, it’s kept in a dark place, and it’s moist and rotten.

Flies will lay their eggs at the bottom of garbage cans and in garbage bags directly on top of the garbage.

Reproduction is the main goal of an adult fly, so it’s critical to prevent their endeavors as often as possible. You can learn more about their lifespan and life cycle in this article.

Types of Flies

House flies are usually what you’ll find in the trash, although blow flies and the occasional mosquito might call this place home, too. 


Keep a tight lid on your garbage and take it out to the dumpster frequently.

Trash cans inside your home, especially in the kitchen, should be taken out at least once a day to prevent flies from settling in.

Keep outdoor garbage cans away from doors and windows.


Houseplants are a wonderful way to spruce up your home, but they can also be the breeding ground for gnats.

Gnats are attracted to the moist soil plants live in.

When you bring home a new plant, it’s possible you’re bringing home tons of little gnats that you didn’t realize were there.

On the other hand, house flies find many plants to be offensive (a list can be found here), so it might be worth the risk if you’d rather repel house flies and chance bringing in some tiny gnats.

Types of Flies

Gnats are usually what plagues houseplants. They love to swarm around grass and other plants too.


Check the soil before you bring home a new plant. Plant nurseries usually take good care of their plants, but gnats are so small that they can’t always be spotted.

Once you bring your plant home, repot it in clean soil that has been kept in a sealed bag.

Allow your plant to dry up completely before you water it again. Gnats don’t like to live in dry soil.


Water is the source of life, so there’s bound to be some flies hanging around water sources. Standing water is irresistible to many aquatic flies.

Puddles near the back door, birdbaths filled with water, and even the cup of water you forgot about on the table for three days will all be inspected by flies.

Once they’re near your door, they have a chance of flying in the next time you open it.

Types of Flies

Mosquitoes, crane flies, and some gnats like to lay their eggs near water. So, standing water will attract them as they look for a place to lay their eggs. 


Keep water away from the entry points of your home. If you catch rainwater, catch it away from your doors or move it to a different location as soon as you’re able to do so.

If flies are flying around your home, a cup of water might attract them, so keep the cup and straw covered so they don’t land on it. 

After it rains, remove puddles with a broom or leaf blower if you know they’ll stay there for a while.

You may even need to wipe down water spots around windows.


Just like doors, windows are a big entry point for flies. Many flies like to rest on window sills because of the light.

If you have a fly trapped inside, they’ll fly toward the windows when the sun is out.

Types of Flies

The same type of flies that go through doors are also likely to go through windows. House flies are the most common fly that will try to find their way into your home.


Many windows have a glass layer and a screen layer with space in between. Installing this type of window in your home will add an extra layer of protection.

If the screen breaks, flies will still have to get through the glass, which likely won’t happen.

Keep windows closed unless they have a screen. Repair broken screens and caulk up cracks as soon as you’re able to do so.

Final Thoughts

There are tons of ways flies can get into your home. You can minimize the number of flies by sealing up all entry points and keeping your home clean.

Piled up garbage, dirty drains, and standing water will make flies want to come inside.

If you don’t have these things, you won’t see as many flies buzzing around.

We have plenty more tips on dealing with flies. In fact, we have an entire series of fly articles here, each dealing with a specific problem and solution.

Head on over to discover a ton of information.