Mice usually get into a house through gaps around doors, utility lines, vents, foundations, crawl spaces, and the roofline. Start outside and inspect one continuous loop around the house. The CDC says a mouse can fit through an opening about 1/4 inch wide, roughly the width of a pencil.
Check these entry points first
- Exterior and garage doors: Look for daylight, worn weatherstripping, and open corners.
- Utility lines: Check where plumbing, electrical, cable, gas, and HVAC lines cross a wall.
- Foundation and siding: Inspect cracks, missing mortar, sill gaps, and siding transitions.
- Vents and roof edges: Look for loose covers, torn screening, damaged soffits, and gaps around eaves.
Photograph each opening and note its location. A label such as “north wall, cable line” beats a camera roll full of mystery holes.
Use indoor signs to narrow the route
Check behind appliances and cabinets; around pipes, vents, windows, and doors; and inside attics, basements, and crawl spaces. The EPA lists droppings, chewed packaging, nesting material, and gnawed holes among the clues worth checking.
Attic activity points you toward the roofline. Signs under a sink make nearby plumbing gaps a sensible next stop. Garage activity puts the main door seal, side door, and utility lines near the top of the list. Mice are not carrying blueprints, but their signs can still point you in the right direction.
How should you seal a mouse hole?
Match the repair to the opening. The CDC suggests steel wool held with caulk for small holes, and metal, hardware cloth, cement, or similar durable materials for larger gaps. Repair worn sweeps, vent covers, screens, trim, or mortar instead of treating every opening like a caulk problem.
Keep required ventilation and drainage working, and do not pack material against hot or electrical equipment. Get the appropriate trade professional when a repair touches a system you should not modify.
Reduce the reasons mice stay
Exclusion works best alongside dealing with mice already indoors and removing easy food, water, and shelter. Store pantry goods, birdseed, grass seed, and pet food in sturdy containers. Fix leaks and close garbage. This is not a cleanliness lecture. Mice can enter a well-kept home.
Handle droppings carefully
Do not sweep or vacuum dry rodent waste. Follow the CDC cleanup guidance. Large contaminated areas or uncertainty about safe cleanup are good reasons to get qualified help.
When an inspection makes sense
Get help when fresh signs keep appearing, the suspected opening is unsafe to reach, or you are not sure which animal is present. Thrive's Nashville mouse-control service starts with the evidence and travel routes. Homeowners east of Nashville can review the Mt. Juliet service area, and our rodent-control guide covers broader signs.
The short version
Inspect doors, foundations, vents, utility lines, crawl spaces, and roof edges. Use indoor signs to prioritize likely routes, then make durable repairs without blocking ventilation or other building functions.
Need help beyond the article?
If the signs around your property match what you are reading, you can review the related service or call Thrive with the details you have.
