How to Keep Mice Out of Your House This Winter

Last updated October 15, 2026

When nights start getting cold in Middle Tennessee, usually from October on, mice start looking for warm, sheltered places with food nearby. Homes offer all three. A few mice can quickly turn into many, and they contaminate food, chew wiring and insulation, and leave droppings in cabinets, attics, and crawlspaces. The best approach is to keep them out in the first place and to deal quickly with any that get in.

Which rodents move indoors here

• House mice are the most common indoor rodent. They are small, gray to brown, and live comfortably inside walls, cabinets, and attics.
• Deer mice and white-footed mice have white bellies and feet and are more common in homes near fields and woods, as well as in garages, sheds, and cabins. Deer mice can carry hantavirus, so cleanup precautions matter.
• Norway rats are larger, burrow along foundations, and tend to enter crawlspaces, garages, and basements.

Homes near farmland, wooded lots, creeks, and new construction sites, all common around Nashville, often see more rodent pressure in fall.

Signs you already have mice

• Droppings about the size of a grain of rice in drawers, under sinks, behind appliances, or along walls
• Gnawed food packages, wires, or wood
• Scratching or scurrying sounds in walls or ceilings, especially at night
• Shredded paper, insulation, or fabric used for nests
• Dark rub marks along baseboards and around openings
• A musky odor in closed spaces
• Pets suddenly interested in a spot under the stove or behind a cabinet

Step 1: Find and seal entry points

A mouse can squeeze through a gap about a quarter inch wide, roughly the size of a pencil or a dime. Exclusion, meaning sealing those gaps, is the most lasting way to control mice. Walk the outside of the house and check:

• Where pipes, wires, cable lines, and AC lines enter the house
• Gaps under exterior doors and around garage doors
• Foundation cracks and gaps where siding meets the foundation
• Crawlspace vents and access doors
• Dryer vents, attic vents, and roof returns
• Gaps around chimneys and where the roof meets the walls

Use materials mice cannot chew through easily. Pack small gaps with steel wool or copper mesh and seal over it with caulk. Cover larger openings and vents with quarter-inch hardware cloth or metal flashing. Add door sweeps to exterior doors and replace worn garage door seals. Foam alone is easy for rodents to chew through, so use it only alongside mesh or metal. Inside, check gaps around pipes under sinks and behind the stove, washer, and dishwasher.

Step 2: Remove food and shelter

• Store pantry foods, pet food, and birdseed in glass, metal, or heavy plastic containers with tight lids.
• Do not leave pet food out overnight, and clean up crumbs and spills promptly.
• Keep garbage in lidded bins and empty indoor trash regularly.
• Move firewood, lumber, and debris piles away from the house and off the ground.
• Trim shrubs and vines away from the walls and keep grass short near the foundation.
• Reduce clutter in garages, basements, and attics, and use lidded plastic bins instead of cardboard.

Step 3: Trap mice already inside

Snap traps remain one of the most effective tools for homeowners. Tips that help:

• Use more traps than you think you need, placed every few feet where you see droppings.
• Set traps along walls with the trigger end facing the wall, since mice travel along edges.
• Bait with a small amount of peanut butter or a similar sticky food.
• Check traps daily and wear gloves when handling them.
• Place traps where children and pets cannot reach them, or use enclosed trap stations.

Glue traps are widely considered less humane and can catch non-target animals. Poison baits carry risks to children, pets, and wildlife, and mice that eat bait can die inside walls and cause odors. EPA rules limit rodent baits sold to consumers to products packaged in tamper-resistant bait stations. If you choose baits, follow the label exactly, or leave baiting to a professional.

Step 4: Clean up safely

Mouse droppings and urine can carry diseases, and deer mice can carry hantavirus. The CDC recommends that you do not sweep or vacuum droppings, which can stir up particles. Instead:

1. Air out enclosed spaces for at least 30 minutes before cleaning.
2. Wear rubber or plastic gloves.
3. Spray droppings and nesting material with a disinfectant or a mixture of one part bleach to ten parts water, and let it soak for about five minutes.
4. Wipe up with paper towels and throw them away in a sealed bag.
5. Disinfect the area, then wash your gloved hands before removing the gloves, and wash your hands again afterward.

For heavy contamination in attics, crawlspaces, or sheds, consider a professional cleanup.

When to call a professional

Call a pest control company if you keep catching mice after a week or two, hear activity in walls or ceilings, find rat burrows along the foundation, or cannot find where they are getting in. A good company will inspect the whole structure, including the crawlspace and attic, point out entry points, and explain whether they offer exclusion work or only trapping and baiting. Prices vary widely with the size of the home and how much sealing is needed, so ask for a written plan that lists what will be sealed, how many follow-up visits are included, and whether any work is guaranteed.

A fall checklist

• Inspect and seal exterior gaps before the first cold snap.
• Install or replace door sweeps and garage door seals.
• Screen crawlspace and attic vents with hardware cloth.
• Move firewood and stored items away from the house.
• Set a few snap traps in the garage, basement, or crawlspace as an early warning.

UT Extension offers homeowner publications on rodent control and exclusion if you want more detail on materials and methods.

Related services

• Rodent Control
• General Pest Control

Sources and further reading

• UT Extension (University of Tennessee Institute of Agriculture)
• Tennessee Department of Agriculture
• U.S. EPA — Bed Bugs
• U.S. EPA — Mosquito Control
• National Pesticide Information Center

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