7 Ways Mice Got Into Your House (And How To Get Them Out)

Mice are cute and all in movies, but seeing one in real life is enough to make you cringe or jump on the nearest piece of furniture. If you have mice in your house, you may wonder how the little rodents got in, along with how to get them out and keep them out!

Mice commonly enter homes through cracks and holes in foundations and walls. Other places mice may get inside include exterior vents, pipes and wires that lead outside, gaps in windows and doors, and even plumbing pipes. Sealing these areas of entry is key to preventing mice inside.

Mice are a common pest that invades homes from time to time, especially in the winter. Let’s check out how those pesky rodents are getting in and how to get rid of them!

How Do Mice Get Into Your House In The first Place?

As fall rolls around and temperatures drop, mice are searching for a cozy, warm place to stay for the winter. Unfortunately, your home is the perfect overwintering spot for a mouse.

Mice are active year-round, but you will find them in homes more often in the colder months. According to the University of Nebraska, these prolific rodents can have 5 to 6 litters per year, each litter containing 5 to 6 mice.

That’s a lot of mice!

The main mouse species responsible for all the droppings and ruined grains in your home is the house mouse, Mus musculus. These sneaky mice can squeeze into spaces ¼ inch wide without a problem, so it’s no wonder they slip into our homes.

But not to worry, we’ll go over all the ways mice can get into your home so you can put a stop to the mouse invasion for good! Let’s check them out…

Mice Can Get In Through Cracks & Holes In Foundation

Have you ever noticed concrete slab floors often have cracks in them? It’s not because the work was done badly. At least… most of the time.

What causes those cracks is the settling of the ground after construction has disturbed it. Soils will fill with water, swell, then lose water and shrink. Roots will grow, expand, die off, and shrink again.

This constant growing and shrinking of the soil cause the floor to move. Over time, cracks form in the concrete, in your foundation, and sometimes in the walls of your home.

While this is normal, it’s also something you need to keep an eye out for and promptly fix. Mice will take advantage of those cracks in no time.

The especially vulnerable areas will be the cracks behind bushes or other landscaping plants that might obscure the opening. They might also be beneath your porch or behind stairs.

Mice Can Enter Your Attic Via Cable Wires or Vines

Your attic is a weak spot in your home because it is typically unoccupied. You don’t know if there is a damaged roofing tile or hole in the wall until you hear the pitter-patter of little mice paws up there.

But how do mice get all the way up in the attic? 

Mice are very acrobatic and can even climb rough vertical surfaces and wire cables without difficulty.

If you have cables leading to the roof of your house, close tree branches, or strong vines creeping up the wall, you may provide mice with a route directly into your home.

Once the little rodents climb up to the attic, they can squeeze through damaged roofing tiles, cracks, holes, pretty much anywhere they can find entry. Tile and shake shingles are more likely to give mice an opening than some other types of roofing materials, especially if they are not grouted properly.

Mice Can Get In Through Exterior Vents

The cool thing about homes is a lot of stuff keeps them running smoothly. Things we do not even have to think about. 

For example, our dryers shoot hot air outside through vents instead of spitting hot air into the house. Our chimneys, bathrooms, attics, kitchens, and foundations often have vents leading outside as well.

Vents help release air to the outside and keep air moving inside the house. They also help reduce humidity and moisture buildup in certain areas, like basements and crawl spaces.

The point is, there are many openings in our home we might not think about. Uncovered exterior vents are the perfect little entryway for a mouse-sized rodent. Most times, the air blowing out of the vents is warm, attracting mice even more.

Mice can easily slip through vents that are not screened or covered properly. Don’t forget about your attic ridge vents or soffit vents as well.

Mice Can Get In Through Your Piping & Sewer System

When you turn on the sink to wash your hands, do you ever take the time to think about where the water goes? Probably not. It just goes down the drain and goes away!

Well, eventually, the water has to lead somewhere, whether it be outside or into the sewers. Some water, like accumulated humidity from an air conditioning unit, will be piped outside and into grass or rocks.

Other water, like from your sink or toilet, is piped into the sewer system, as it needs to be treated before it can be released into the environment or repurposed.

If mice are desperate enough or curious enough, they may sneak their way into your home through the plumbing. They can crawl through the bathtub and sink drains, eventually making their way into the walls, basement, or attic.

This is where you’re likely to hear one of the specific sounds and noises that mice make.

This is more likely to happen in weekend cabins that may be undisturbed for a few days out of the week. As long as there is a rough surface to grab onto, mice will climb and claw their way through the pipes.

Mice Can Squeeze Through Electric Line Openings

Just like the vents and plumbing in our home, we can easily overlook wiring holes as a potential mouse entry point. 

Any area where cable wires run from outside to inside is a potential entry point.

The space around the wiring may look small, but mice can fit through the smallest of spaces – ¼ inch! So be on the lookout for these types of openings.

Mice Will Fit Through Gaps In Doors & Windows

It’s nearly impossible to seal every single hole, gap, or crack in your home. But one of the big ones you can look for is the gaps in your doors and windows.

Your doors may look solidly closed, but if the hinges are slightly crooked, mice can slip through the bottom or sides of the door with little trouble. You can check for this using a flashlight on one side and shutting off the lights on the other side of the door.

Old wooden doors that are chipped at the bottom are vulnerable to chewing as well, which can widen the gap enough for a sneaky rodent to slip through.  

Windows can be a vulnerable area for critter entry too. Just like doors, windows can sit slightly crooked in the frame, giving mice a way inside. 

Mice can easily chew door and window screens made of lightweight plastic mesh, giving them easy access to your home. If there are already holes or rips in the screens, it makes chewing through it much easier.

Mice Will Use Your Fireplace To Enter Your Home

Move over Santa. You’re not the only one in town using the chimney to get in the house! Mice have been known to enter homes via the fireplace when it is not in use.

Some fireplaces are more likely to allow mice entry than others. Not all fireplaces are the old-fashioned brick-and-mortar chimney style. Unfortunately, mice can gain entry to your home using almost any type of fireplace.

According to the University of Nebraska, pre-constructed fireplaces that are not brick and mortar are the most vulnerable to mice. This is because there is a hollow space left between the siding and the fireplace.

If a mouse can find their way inside, it will have free access to the rest of your home…

Brick and mortar fireplaces also pose a problem for homeowners looking for a mouse-free house. The rough texture of the bricks can give mice enough of a grip to crawl up and down the chimney.

How To Get Mice Out Of Your House

Now that you know how the mice are getting inside, it’s time to do something about the actual mouse in your house. You can attempt to take care of the problem yourself, or you can hire a local professional to remove the mouse.

If you decide to tackle the problem on your own, there are a few things you can do to make the process easier for yourself. Let’s check out how to get that mouse out of your house.

Locate The Mouse Hot Spots

The first step in getting a mouse out of your house is to figure out where it hangs out the most. This information will be invaluable in getting pesky rodents out of your home.

Some of the most common areas that mice like to hang out include:

• Along kitchen baseboards
• On kitchen counters
• In cupboards and drawers
• Basements
• Attics
• Above drop ceilings
• Near large appliances
  • Refrigerator
  • Dryer
  • Hot water tank
• Furnace room

If mice are invading in the wintertime, your best bet is to check areas that provide warmth such as near large appliances and in furnace rooms. At any other time of the year, you can find mice just about anywhere.

To figure out where the mice are roaming inside your home, look for evidence of mouse activity. Check for droppings, crumbs, holes in food bags, or food with little nibbles taken out of it.

Once you establish the main areas where the mouse (or mice) are moving around in your home, you can move to the next step!

Set Out Traps To Catch Mice

Mice that have made their way inside your home are not likely to leave on their own. If they have a cozy place to sleep and a bit of food and water, they have everything they need to survive.

Plus, if you don’t have cats, there are no predators in your home.

Having mice in the home differs from having a squirrel, raccoon, opossum, or bat. These animals will leave on their own to forage for food. Mice do not need to leave your home to find food.

An adult mouse only needs around 3 grams of food per day to survive. So, a few little crumbs dropped on the floor is enough to keep a mouse fed. If they keep finding them, why would they ever leave the safety of your home?

For this reason, using mouse traps is about the only way you can get mice out of your home. The only exception is during the summer. Mice may leave on their own during this season because it is warm outside and food is plentiful.

There are two major categories of traps you can use for mice: the ‘catch and release’ kind and the ‘catch and dispose of’ kind.

For the catch and dispose of kind, you can use something like the Kat Sense Mouse Traps. These are like the old-fashioned snap traps, but they have been redesigned to be more effective and humane.

Once the mouse is caught, you can dispose of it by releasing the snap while holding the trap over your trash can.

If you would rather use a catch and release product, Gerossi’s Humane Catch and Release Mouse Traps are a good choice. This product comes with a pack of two, so you can place them in different hot spots.

So, which one is better? Catch and release or catch and dispose?

It’s all about what you are comfortable with. Both traps can be quite successful in getting rid of those pesky mice.

However, the main point to take away here is that no matter what trap you use, if you do not seal all entry points to your home, another mouse is likely to move in.

Note: With catch and release traps, be sure to set the mouse loose near your home. Relocating mice far from their original home will not help the mouse and they likely cannot adjust or survive.

If you’d like to learn more about their habits, take a look at our guide on where mice go and live during the day!

What About Glue Traps & Rodenticides?

Sticky boards and glue traps are products that will catch mice and cause their paws to stick to the board. Rodenticides are baits laced with anticoagulants that will cause a mouse to perish.

Both techniques are not recommended to get mice out of your home unless you’ve consulted with a professional about your specific situation.

Glue traps are not humane and the mouse will take a long time to perish via starvation. They can also catch non-target species like lizards, spiders, other small mammals, and birds.

Rodenticides are also not humane because they take a long time to work. The mouse will ingest the bait and then go back to its nest before perishing. If their nest is inside your walls, the mouse can cause an unpleasant odor.

It’s best to stick with quick snap traps or catch and release traps.

You can also place certain scents that mice hate in the potential areas they enter to help them avoid ever entering in the first place!

How To Prevent Mice From Reentering Your House

No matter which method you use to get mice out of your home, they will keep coming back unless you seal all the little holes and cracks they are getting through.

But sealing holes is only one part of preventing mice from invading your home!

Seal ALL Potential Mouse Entrances

This step may sound obvious, but as we said before, there are some openings in your home you may not be aware of.

For a quick reminder, here are all the openings where mice may get inside:

• Cracks & holes in the foundation
• Damaged roofing tile
• Chimney openings
• Exterior vents
• Cable wire entires
• Plumbing pipes
• Gaps in doors & windows

For many of these openings, you can use something like PS Direct Hardware Cloth. This product is 36 inches X 10 feet per roll and the openings are only ⅛ inch. Definitely small enough to keep mice out!

Use the mesh to cover chimney openings, exterior vents, cracks, holes, and drain pipes. For the areas around plumbing pipe and cable wire, shove the mesh into any open space around the pipes or wires.

It does not need to fit perfectly around the pipe or wire, it just needs to block mice from getting through.

For broken or damaged roofing tiles, you will want to replace them. Using wood, plastic, or rubber will not keep mice out, as those troublesome rodents can chew through just about anything.

Similarly, using caulking to fill holes and cracks will not keep mice out. They will chew through it and keep sneaking inside.

If you have more questions about using hardware cloth, take a look at our article that explains whether or not mice can chew through stainless steel mesh.

Habitat Modification

Sealing your home is an excellent solution to your mouse problem. However, sealing every hole may be impossible, especially in older homes.

One way to reduce the presence of mice in your home is to make your yard less attractive to mice. Mice do not have a large home range, so if they’re getting inside, they’re probably living very near your home.

Brush piles, unruly stacks of wood, unused boards, and building materials are all possible nesting locations for mice. They like areas that are covered, warm, and safe from predators.

Try to keep your bushes trimmed so they are not touching the ground. Stack wood neatly and, if possible, off the ground. Discard unused boards or other materials. Trim vines or tree branches that grow close to your home.

Bird feeders are another mouse attractant. Mice will nibble on seeds, including birdseed. Do not worry, you will not have to take down your bird feeder to keep the mice away.

You can use something like Pranovo’s Bird Seed Catcher Tray. It hangs directly from your existing bird feeder and catches all the falling seeds. This will eliminate birdseed that falls to the ground, thus keeping mice and other critters away.

Pet food and water dishes are other mouse attractants. Try to feed your pets indoors or pick up their food dishes each night to avoid attracting mice.

If you are finding mice in your vehicle instead of your home, you can check out our step-by-step guide, on getting mice out of your car here!

Wrapping Things Up

For how small they are, mice can cause a lot of headaches and damage! The little rodents might be cute on TV, but seeing one in real life inside your home is not.

There are a few reasons mice are in your home: warmth, food, shelter, nesting. The good news is, there are ways to get them out and keep them out for good.

Areas like your foundation, doors, windows, attics, chimneys, exterior vents, piping, and cable line entrances are all vulnerable areas. Mice can slip through the smallest of openings – ¼ inch. 

You can use mouse traps to remove mice from your home, but they will keep coming back if your home is not sealed properly. 

Be sure to use metal or concrete to block all your openings so that mice cannot chew through the sealant. 

Using these techniques works well with a mouse here and there, but it’s not meant to work with a full mouse infestation. If you find your home overwhelmed with mice, you can always reach out to a professional. 

Our nationwide pest control finder can help you get in touch with a wildlife control professional near you!

References

Hansen, S. C., Stolter, C., & Jacob, J. (2015, December). The smell to repel: The effect of odors on the feeding behavior of female rodents. Crop Protection, 78, 270-276.

Morris, C. F., McLean, D., Engleson, J. A., Fuerst, E. P., Burgos, F., & Coburn, E. (2012, February 29). Some observations on the granivorous feeding behavior preferences of the house mouse (Mus musculus L.). Mammalia, 76(2).

Singleton, G. R., Tann, C. R., & Krebs, C. J. (2007, March 15). Landscape ecology of house mouse outbreaks in south-eastern Australia. Journal of Applied Ecology, 44(3), 644-652.

Sked, S., Abbar, S., Cooper, R., Corrigan, R., Pan, X., Ranabhat, S., & Wang, C. (2021, March 01). Monitoring and Controlling House Mouse, Mus musculus domesticus, Infestations in Low-Income Multi-Family Dwellings. Animals, 11(3), 648.