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How to Get Rid of House Mice: A Comprehensive Guide

July 12th, 2024 | 6 min. read

By Louis Greubel

A mouse inside of a cardboard tub that is propped up against a wooden ledge. The animal's ears are up, and it appears to be looking at the camera.

It’s no secret that mice love to get inside our homes. The classic cartoon trope of the little rodent scurrying into the arch-shaped hole in the base of the wall to gnaw on its cheese is decades-old.

But in reality, a mice infestation is far less entertaining than an episode of Tom and Jerry. It’s frustrating, typically expensive to resolve, and potentially harmful to your health.

But how do you know whether or not you have mice, anyway? What should you look out for? How do they get in? And, most importantly, how do you get — and keep — them out?

At HY-C, we manufacture dozens of nuisance and wildlife control products under our HY-GUARD EXCLUSION brand name. We’re also a partner of the National Wildlife Control Operators Association (NWCOA) and the National Pest Management Association (NPMA).

And in this guide, we’re going to explain exactly how to handle a mice problem.

We’ll cover some frequently asked questions about mice, how they get into your house, and methods you can use to get rid of them. We’ll also explain some myths around mouse deterrents and the best way to actually keep mice from coming back.

By the time you’re finished here, you’ll know everything you need to find, eliminate, and prevent a mouse infestation.

Mice: Frequently Asked Questions

The best way to stop a mouse problem (or any nuisance wildlife issue, for that matter) is to know as much as you can about the biology and habits of the animal. With that in mind, let’s address some of the most common questions people have about mice.

When Do Mice Infestations Occur?

Mice tend to get into homes during the fall months. As the weather gets colder and food becomes scarcer, they need warmth and shelter — and homes are an ideal environment for them.

How Long Do Mice Live?

The lifespan of a mouse is typically between 6 months and 2 years, with species and habitat playing a key role in how long the critters can survive.

How Many Young Do Mice Have?

Female mice typically bear between 6 and 12 young (called pups) at a time. From conception to birth, the pregnancy usually only takes 20 days. This short gestation period is why infestations tend to spiral out of control so quickly.

Can Mice Climb?

Mice can easily climb trees, bushes, and more vegetation. When it comes to homes, brick essentially acts as mouse scaffolding. They can scale it with ease.

Do Mice Have Rabies?

It’s very, very rare for a mouse to have rabies, and there are no documented cases of mice passing rabies on to humans. On the other hand, they can spread hantavirus through their urine, saliva, and feces, posing a threat to any residents in the home.

Do Mice Bite?

If a mouse feels threatened, it can (and will) bite you. Avoid picking them up if you see one. And if for any reason you are bitten, wash your hands thoroughly with soap and hot water and notify your doctor as soon as possible.

How Do Mice Get in Your House?

It’s shocking how little room a mouse needs to get into a home. They can squeeze through holes just a bit bigger than the width of a regular pen (around ⅜”). Even the smallest cracks or holes in any part of your home can result in a mouse gaining access.

That said, some entry points are more common than others. And if you know where they are, you may be able to stay one step ahead of them.

How to Find Mice Entry Points

Aside from any structural or exterior damage, the following are some of the most common vulnerable areas mice use to get into houses.

HVAC Line Sets

HVAC lines running into a hole in the side of a home. There is a gap between the HVAC line and the side of the hole.

Heating and cooling pipes need to get inside your house somehow. To set them up, contractors drill holes in your wall and run the pipe through. Once the lines are in place, they’ll seal them up with caulk.

Over time, however, weather damage can cause the caulk to crumble. Also, the lines themselves may shift, leaving an opening small enough for a mouse.

Siding Gaps

A close-up of the point at which the foundation of a home meets its siding. There is a clear gap between the siding and the foundation.

Check the spot where the foundation of your home meets the siding. As your houses settle over time, a gap can open up in this spot. Mice can exploit it to get inside your walls.

Sealant can help, but as with the HVAC line sets, it’s not a permanent solution. Products like Pest Armor can be installed along these gaps to keep mice and other animals out for good.

Crawl Space Vents

A foundation vent installed in a cinder block foundation. The vent is unsecure and beginning to come loose from the foundation.

Foundation and crawl space vents tend to be made of aluminum, a thin metal that’s highly susceptible both to environmental damage and animal tampering. Mice can easily squeeze through these vents even if they’ve only been slightly damaged.

A good foundation vent screen, on the other hand, is made from steel. These screens can stand up against weather and wildlife alike, keeping mice out.

Gable End Vents

A white, octagonal gable end vent installed on the side of a house with a brick face.

A common entry point for bats, gable end vents are vulnerable to mice, too — especially if they’re installed on a brick facade. Mice can easily climb up the brick face of a home, squeeze through the gable vent, and quickly make a home in your attic.

Roof Vents

A black, hood-style roof vent on a home with dark-gray shingles.

There are several types of roof vents, and mice are small enough to get past nearly all of them. If a tree or a tall bush grows alongside your home and hangs over your roof, mice can access the roof and bypass the vents to get into the attic. You can prevent this by installing roof vent guards.

How to Tell if You Have Mice in Your House

A mouse chewing on an electrical wire that is plugged into a socket. There are frayed wires and a bit of mouse poop on the floor.

Mice are small and nocturnal. Combined, these factors often make them hard to detect until an infestation has grown out of control. Luckily, though, there are a few key indicators to help you tell whether or not a mouse may be living in your home:

  • Feces: Mouse poop is dark and shaped like a grain of rice (though it’s actually a bit smaller than rice). They tend to defecate along travel routes, too, as opposed to one set area. So look for lines of small, brown, rice-shaped feces.
  • Chew marks: Mice love to chew. If your electrical wires, furniture, or food shows signs of small bite marks, a mouse may be to blame.
  • Nests: Mice make nests just like birds. They can be made of all kinds of materials, like cardboard, paper, straw, cotton, fabric, and more. If you find one, you likely have mice.
  • Smell: You probably won’t smell a mouse’s poop, but if there are enough of them, their urine can be particularly pungent.
  • Noise: Keep an ear open for scratching sounds or scurrying coming from inside your walls or attic.

Be on the lookout for any of these indicators. If you start experiencing two or more of them, that’s very strong evidence that you have a mouse problem.

How to Get Rid of Mice

A side-by-side image. On the left is a mouse trap, and on the right is a person setting out some blue rodenticide.

Unfortunately, it’s very difficult to catch mice humanely. The most effective means of removing a mouse usually involve killing the animal. That said, there are two way to go about it:

  1. Mouse traps
  2. Rodenticides

You can hire a wildlife control operator or a pest management professional to handle the problem, or you can attempt to take it on by yourself. The method you use — traps or toxicants — can depend heavily on where the critters have settled in.

How to Get Rid of Mice in the Walls

If you have mice inside your walls, that means one of three things:

  1. They’re coming and going from outside your home
  2. They’re coming and going from inside your home
  3. They’re coming and going from both outside and inside your home

Either way, setting mouse traps is your best bet. You can find these traps from companies like Wildlife Control Supplies or Animal Traps and Supplies.

Be sure to identify the entry points they’re using and set several traps. You can also attempt to discover their travel routes by looking for trails of feces. Usually, these routes run alongside a wall. Set the trap perpendicular to the wall to catch the mice either coming or going.

When baiting the traps, don’t use the same food for each one. Mix it up. New and different food will keep the critters interested.

Also, don’t rely solely on food as bait. Mice need materials to build their nests. Adding some stray cotton or loose fibers can draw them in just as easily as something edible.

How to Get Rid of Mice in Your Attic

You can certainly set traps in your attic to deal with a mice infestation, but that may require going up there to check the traps often. That can be a lot of work. Instead, for an attic infestation, most people prefer to use rodenticides.

Coming in the form of pellets or blocks of food, these toxicants don’t kill mice right away. It takes several days to a week for the animal to succumb to their effects after they’ve ingested them. This provides plenty of time to get rid of as many as the fast-reproducing critters as possible.

Rodenticides are a good choice for mice in attics because children or pets living in the home will be far less likely to ingest them accidentally than if they were in a kitchen or living room.

Can You Repel or Deter Mice?

A container of cinnamon, a box of Arm & Hammer baking soda, and a bottle of peppermint oil side-by-side against a white background.

Identifying, trapping, and baiting are hard work. Surely there are easier remedies to take care of a mice problem, right?

You may have heard several catch-all solutions like dryer sheets, peppermint oil, mothballs, baking soda, or cinnamon. The idea here is to repel mice naturally with a smell that they hate.

The truth is, though, these “solutions” offer temporary success at best and complete ineffectiveness at worst.

Imagine that a set of train tracks is built just a few hundred yards from your house. At first, the constant noise of the train would probably drive you crazy. But after a little while, you’d simply grow used to it. In fact, many people live near trains or airports and just become accustomed to the noise.

The same is true of mice and deterrents. Once they’ve identified your home as their shelter, a little bit of peppermint oil isn’t going to drive them away. You’ll need a more permanent solution.

How Do You Keep Mice out of Your House?

After the last mouse is gone, the job is not yet finished. The final step is to ensure no mice come back. But if deterrents can’t repel them, how do you keep them out?

The most effective way to keep mice (and any other nuisance wildlife) from getting in your house to begin with is through a process called wildlife exclusion. This process involves installing physical barriers over common wildlife entry points to lock them out permanently.

Our HY-GUARD EXCLUSION product line offers several wildlife exclusion screens and guards to keep critters out of bathroom vents, roof vents, chimneys, and more. And, with the help of a wildlife control operator, you can secure your home against mice, bats, squirrels, and other common nuisances.

Louis Greubel

Louis earned a bachelor's degree in English with a focus in rhetoric and composition from St. Louis University in 2017. He has worked in marketing as a content writer for over 5 years. Currently, he oversees the HY-C Learning Center, helping HY-C subject matter experts to share their decades of home solution products experience with homeowners and sales partners across the country.