How to Keep Mice Out of the House

Rat in the house
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Unless it's your pet mouse or rat in a cage (which may still cause some family members to jump on a chair if it gets loose), any wild rodent in your home is cause for concern. In addition to startling you with unexpected sightings, rodents such as mice and rats can contaminate food, chew up important papers, damage electrical wiring, and spread disease. In addition to fires caused by when the insulation on electrical wiring is chewed through, these rodents can carry diseases such as the hantavirus, which is transmitted through accidentally inhaling dust containing an infected rodent's dried urine.

It can be quite difficult to completely eradicate rats or mice that have infiltrated your home and established hidden nesting areas, so it's best to prevent infestations before they can happen. When you do find your home playing host to mice, rats, or other unwanted rodents, take whatever measures necessary to remove those pests and block their entry points into your home.

Signs of Rodent Presence

When a mouse or rat decides to visit, it often goes unseen—at least at the start. Usually, signs that rats or mice are present include small dark droppings (feces) that look like tiny grains of rice that are found along walls or in places where food materials are present. You may also notice other destruction, such as chewed holes in boxes and bags of dry goods in a pantry, in pet food bags, or in bags of grass seed in the garage.

Close inspection along baseboards or near any holes in the floors, such as where radiator pipes come through, may show rub marks or gnawed areas where the rodents have chewed to gain free access. In hidden areas beneath cabinets, you may find small nest areas filled with shredded paper or wood shavings.

If you have pets, your dog or cat may exhibit alert behavior, sensing the presence of a rodent. And you may even hear sounds of scurrying or scratching in the walls or floors, especially at night when the house is silent and dark.

Learn how to keep mice out of the house with these 11 best, and mostly poison-free practices.

  1. 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 are seeking to get in from the cold, is an especially good time to run your inspection tour. Mice can enter by squeezing their way through the smallest cracks, so block foundation cracks with a masonry repair material, and inspect joints around windows and doorsills 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, unless you use spray foam insulation, which may help keep rodents at bay.

  2. Keep Bird Feeders Far From 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 the 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.

  3. 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 make sure to store them in tightly sealed containers well above the floor.

  4. 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 airproof 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.

  5. 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 foundations 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.

  6. 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.

  7. Clean Floors and Countertops

    Casual housekeeping, especially in the kitchen, 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.

  8. Close Outside Doors

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

  9. Set Live Traps and Baits

    Mostly as a diagnostic measure throughout the year, set a few live 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. A bait station contains poisonous and thirst-producing pellets that make the rodent seek water outdoors where it dies. It is much easier to catch one or two mice or rats at the start of an infestation than to deal with it after a whole colony has set up a home in your walls. Put any type of live trap or rodent poison baits completely out of reach of children and pets.

    Poison Bait Dangers

    If you must use poison baits, never set them outdoors, since squirrels and pets will find and eat them. Rodent poisons are a major cause of pet poisoning in the United States, and indoor mice that are killed by poisons may die in the walls, leaving you with the issue of their decaying remains.

  10. Use Holistic Repellents

    Though this is purely a preventative measure, add safe and holistic repellents around the inside and outside of your home. Peppermint oil is known to irritate a rodent's nasal passages thanks to its strong menthol odor. Try growing peppermint leaves around the perimeter of your home or spray essential oils around your home to deter their entry. If you don't like the smell of peppermint indoors, instead, try spraying a bit of clove essential oil.

  11. Adopt a Pet

    A pet, such as a cat that loves to hunt prey, or even a barn owl, can be the best 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. But a 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 and reproduce.