How to Keep Mice Out of Your House

Block All Entry Points

The single most important preventive measure you can take to keep mice and rats away is to inspect the foundation and walls of your house to make sure any potential entry points are blocked.

The fall season, when rodents seek to get in from the cold, is an especially good time to run your inspection tour. Mice can enter by squeezing their way through cracks as small as 1/4-inch in diameter, so block foundation cracks with a masonry repair material, and inspect joints around windows and door sills for cracks that might allow rodents to enter.

Make sure weather seals along the bottom edges of garage doors are in good shape. If your garage is insulated, it may become a cozy home for a rodent.

Check your attic, as well, since rodents love the warmth of insulation. However, there's no completely effective rodent-proof insulation on the market as of yet, although spray foam insulation may help keep rodents at bay.

Move Bird Feeders Far From the House

The seeds and ground grains that go into most bird-food mixtures are a delightful treat for rodents, as evidenced by the presence of squirrels (larger cousins to rats) that frolic around any bird feeder.

Feeding birds is an admirable hobby, but you shouldn't be surprised when mice and rats are drawn to the ground around your feeders. If you must feed birds, keep your feeders as far from the house as possible.

Seal Pet Food

Transfer dog and cat foods to sealed, airtight storage containers immediately after buying them. More than one homeowner pouring a bowl of dog food has dumped out a squeaking mouse at the same time.

Dry pet foods are mana from heaven for rodents, so store them in tightly sealed containers well above the floor.

Seal Garbage Bins

Garbage cans and bins kept alongside the house or garage will be a siren call to rats and mice (and maybe bigger pests, such as raccoons or stray dogs and cats) unless they are kept tightly sealed with air-proof lids.

If possible, keep these utility containers as far from your house as you can, put them on platforms above the ground, and as an added prevention, secure lids with bungee cords or heavy rocks.

Control Foundation Plantings

Dense shrubs and garden planting that butt up close to the house provide hiding spots for mice and rats (and termites) as they seek entry holes through foundations or walls.

Shrubs along the house should be planted a few feet away from the foundation, and make sure to keep the soil level low enough that mice cannot squeeze their way up behind the siding.

Seal Dry Foods

Flour, sugar, and other food kept in bags or paper cartons are easily broached by rodents and bugs, such as weevils. Instead, keep these foods in tightly sealed plastic or metal containers on high shelves or in the refrigerator.

Rodents will have no incentive to take up residence in your house if they don't smell any source of food.

Clean Floors and Countertops

Casual, messy housekeeping that leaves spilled crumbs or food scraps on floors or countertops is an invitation for mice and rats. Always have a handy sweeper to capture crumbs and never leave uneaten bowls of pet food in dishes on the floor.

If you have a pet bird, sweep up scattered seeds that have fallen on the floor under the cage.

Keep Outside Doors Closed

Garage doors left wide open can be an invitation to rats and mice, especially in the fall when these rodents are seeking a warm place for winter.

Get into the habit of closing your garage door immediately after entering or exiting with your car, and also keep side entry doors to the garage closed. Keep sliding patio doors and basement windows closed, or at least protected with screens, to prevent rodents from entering.

Never leave a garage door, or other entries open overnight, as the dark hours are when rodents are especially active.

Set Traps and Bait

Mostly as a diagnostic measure throughout the year, set a few traps and bait stations indoors. A live trap is a humane and poison-free way to trap and release rodents while alerting you when they are finding entry into your home.

The best live traps are chamber-type devices with a spring-loaded door that snaps shut when the mice enter in search of food. Avoid sticky trap designs, since mice have been known to chew their own feet in an effort to free themselves from the adhesive—these traps are by no means humane.

If you have no qualms about killing mice, then traditional spring traps are a good choice; they usually kill mice very quickly and without much pain to the creature.

Use Natural Repellents

In one study, eucalyptus oil showed some success in repelling rats. But efficacy was improved when the oil was applied daily and alternatively as compared to when applied once a week indicating low persistence of the repellent effect due to the volatile nature of the oil.

Adopt Pet Predator

A pet that loves to hunt prey, or even an owl nesting outdoors in your garden can be excellent rodent control. But because pet food is always present in a house with pets, rodents may find your home to be a good source of food.

However, a young, aggressive cat, or a dog species such as a terrier with a reputation for hunting small animals, can often catch rodents before they can take up housekeeping and form nests to reproduce.