How to Get Rid of Mice in Your Garage

A mouse infestation in your garage can create a surprising amount of damage and debris. The mice might chew walls and electrical cords, as well as leave food waste and droppings. Plus, they can carry diseases.

Fortunately, it’s usually fairly easy to get rid of mice in the garage. Here’s what you need to know.

Signs of Mice in a Garage

Pay close attention to catch signs of a mouse infestation in the garage, mainly because these spaces are often cluttered and you likely don't spend much time there. If you suspect an infestation (or see a mouse), listen for squeaking or rustling in the garage (particularly at night), and check wires, walls, and bags of feed or seed for nibble marks or other damage.

You should also look out for unusual odors (like urine), holes in any materials that weren't there before, rodent nests, or scratching or scampering noises. Check the floor along the edges of the room for droppings. If necessary, move large items the mice might be nesting under or inside to look for signs.

What Do Mice Look Like?

Mice belong to the Rodentia order and Mus genus and infest homes and garages, seeking shelter and food. Garages are especially vulnerable to infestations due to an abundance of food sources, such as bird and pet food.

The best-known species of mouse in the U.S. is Mus musculus, the 3- to 4-inch-long brownish house mouse with a pointed nose and long tail. There are also a number of field mice from the Apodemus genus and deer mice from the Peromyscus genus that can, under some circumstances, infest a home, garage, or outbuilding. These rodents are very similar to house mice, except for having white bellies rather than the solid-colored coat found on the house mouse.

Mice vs. Rats

Another type of rodent that can be a serious garage pest has two types - the black rat (Rattus rattus) and the brown rat (Rattus norvegicus). Black rats are black to light gray in color and 5-7 inches long. Brown rats are brown or light gray and can be 13 inches long or more. Some white varieties of the brown rat have been domesticated as pets.

Rats can be considerably more damaging in a home or garage, and they are also carriers of disease. But methods for eliminating and preventing them are largely the same as for mice. Trapping requires much larger, stronger traps.

5 Ways to Get Rid of Mice in the Garage

Here are five common methods that are effective for ridding your garage of mice.

Spring Traps

Very simple in design, traditional spring traps use a triggering bait tab that loosens a spring-metal bar that snaps down on the offending rodent when it applies pressure while feeding. The iconic bait for catching mice is cheese, but almost any food substance will do.

Ideally, the traps will snap down on the necks or bodies of the rodent, and death from suffocation is usually fairly painless and quick. The creatures are not crushed, as some people think.  There are instances, however, where the mouse will be caught by the leg or even tail, and here you may need to carefully dispatch the still-living mouse in another fashion.

Check the traps frequently. A dead mouse will soon announce its presence from the odor of decay, at which time it’s much less pleasant to deal with.

Sticky Traps

Using a very sticky wax-like substance, glue traps capture any mouse that wanders onto the sticky pad while in search for food. These are sometimes thought to be more humane than spring traps, but a mouse can remain for hours trapped this way and might even chew its own paws trying to escape. And if you do trap a mouse, you’re left with then killing it anyway. It is nearly impossible to extricate a live mouse from a sticky trap.

Sticky traps appeal mostly to people who are uneasy about setting spring traps, but they are no more effective and in many ways are less humane.

Live Traps

If killing a mouse is repugnant to you, there are a variety of live traps you can use to catch them. Most designs have some method of baiting the rodent to enter, then tripping a door or hatch that traps the live mouse.

But you will then need to figure out what to do with the live mouse. Released in a residential area, and you’re just off-loading your own problem on someone else. Released in the countryside, you’re just making the mouse a burden for a farmer. If you must live-trap, perhaps releasing the rodent in the woods or another other wildlife area is the best solution, but remember that here the rodent will likely quickly become a food source for an owl, fox, or hawk. Such a fate is by no means more humane that dispatching the rodent through a traditional live trap.

Rodent Bait

A variety of poisons can be used to kill mice. Many of these use an anticoagulant substances, which act by causing the rodent to bleed internally, usually over the course of several days. In addition to the pain this must create for the mouse, the pellets, tabs, or bait stations can be found by pets or children, and if the substances are eaten, they can cause serious illness or even death.

There are also other toxins used to kill mice and other rodents, and most can be quite toxic for pets and humans. Rodent poisons are not a good choice for homes with pets and children. Nor are they a good choice for garages because the poisons are often carried outside, where wild animals often find them. Small predators like foxes or owls that eat mice contaminated with poison can also be affected. All in all, poison bait is not the best choice for ridding your garage of mice.

Keep a Cat or Dog

Not just any cat or dog is a hunter that will find and kill mice. In fact, statistics show that homes with domestic pets are sometimes more likely to have mice, largely because they also contain stored pet foods.

However, the right kind of house cat, and certain dog breeds, can be very effective at catching mice. Aggressive young cats can sometimes be very skilled mousers, and many terrier species of dogs are bred specifically to catch small animals. If you're lucky enough to have this kind of pet, give it a few hours each week of hunting time in your garage, preferably at night.

What Causes Mice in a Garage?

Mice are a common problem in a garage because these spaces typically have many dark places to hide and nest, they often have good food and water sources, and there are usually plenty of cracks and crevices that allow them to come and go easily. In other words, if a space was designed to shelter mice, it would look a lot like a typical garage. On the other hand, spotlessly clean, well-lit, and airtight garages will not be very attractive to mice and other rodents.

How to Prevent Mice in a Garage

Preventing mice in a garage is largely a matter of denying them their nesting and hiding areas; eliminating food and water sources; and plugging and blocking any cracks, holes, or crevices that allow them to enter. Begin your efforts at prevention by first trapping or baiting any mice already in the garage. At the same time, begin to declutter your garage and seal holes.

• Keep food sealed or out of the garage. And put dog food, fertilizers, and grains in tightly sealed plastic containers.
• Keep the landscaping around the foundation of your home free of brush and thick layers of mulch.
• Carefully inspect concrete slaps and foundations for cracks, holes, and crevices, and fill these with concrete patch. With wide cracks in wood walls, stuffing them with steel wool before patching them over can prevent additional gnawing.
• Commercial rodent-repellant chemicals are available. But if you are leery of commercial repellants, you can concoct a more natural mixture that mice hate. Mix 2 tablespoons of hot pepper sauce (the hotter the better) in a gallon of water with several drops of liquid soap. Spray it on the outside of the garage. It works just like commercial repellents and won’t harm your pets or children. 
• Peppermint is a natural mouse deterrent and is environmentally safe. Spray a solution of peppermint extract and water around the perimeter. This solution needs to be sprayed once a week and after rainstorms. Or you can plant peppermint around the foundation of your home and garage. The smell repels rodents and perfumes your home. (Note that while peppermint oil can help deter mice from entering your home, it is much less effective at removing mice already living there.)
• For another eco-friendly solution, use ultrasonic mouse repellers inside the garage. An ultrasonic mouse repeller is inaudible to humans, but the sound it produces is very painful to mice. Mice will not enter a room where this device is humming. 

The reality is that mice will usually find a way into a garage, and “preventing” them usually means some form of ongoing seasonal effort. In colder climates, mice will be particularly troublesome during the fall, as the rodents begin to seek warm dark areas to overwinter.

When to Call a Pro

Eliminating mice from a garage is usually easy enough, but sometimes a severe infestation is more than you can handle yourself.

If you hear mice scratching in unseen areas of the garage or within the walls, if you're unable to trap them, or if you continue to see droppings after all methods have been tried, it's time to call a professional exterminator. A professional can help you identify how the mice are entering your garage and can resolve your issues faster than a do-it-yourself approach. Even better: They can offer solutions that are both pet- and family-friendly.