How to Get Rid of Mice: Trapping, Sealing, and Preventing Re-Entry (2026)
Mice in the house require trapping the current population and sealing every entry point. This guide covers identifying entry points, choosing effective traps, placement strategy, and exclusion to prevent return.
Mice in the house: set snap traps, not poison bait. Poison bait kills mice inside walls where they decompose and attract secondary pests; snap traps produce a contained, disposable kill. Place snap traps perpendicular to walls (mice run along wall edges, not across open floors) with the trigger end against the wall. Use peanut butter — a pea-sized amount pressed into the trigger. Set traps in every room where you've seen droppings. Replace bait every 2–3 days. After catching begins: seal every entry point with steel wool and caulk.
Frequently Asked Questions
How do I find mouse entry points?
Mice enter through holes as small as 1/4 inch (the size of a dime). Common entry points: gaps around utility pipes and wires where they enter the foundation or walls, gaps under the sill plate at the foundation level (visible in the basement or crawl space), gaps around dryer vents and HVAC penetrations, gaps under garage doors, unsealed crawl space vents, and openings around conduit. Inspect the exterior foundation at ground level with a flashlight — look for any hole, crack, or gap. Inside: look for entry points under kitchen and bathroom cabinets, in corner gaps, and near the water heater and furnace.
What is the most effective mouse trap?
Victor Original snap traps (the classic wooden base + wire bail) are the benchmark for effectiveness and economy — $2–$3 each. Modern plastic snap traps (Victor Easy Set, Tomcat) are comparable and easier to set without risk of finger injury. Electric traps (Victor Electronic Trap) are effective and more hygienic — they deliver a high-voltage kill and are enclosed, so no visible mouse. Glue traps are inhumane and inefficient — mice can escape and carry pathogens; avoid. Live-catch traps relocate the problem unless you release the mouse at least 1 mile from your home. For a house with an active infestation: set 6–12 snap traps the first night — multiple catches on night one indicates a larger population.
How do I seal mouse entry points permanently?
Seal using materials mice can't chew through: (1) Steel wool — stuff large gaps (1/2 inch to 2 inches) tightly with steel wool. Mice don't like to chew through it. Follow with caulk over the steel wool to hold it in place. (2) Copper mesh (Stuf-fit) — similar to steel wool but more durable; doesn't rust. (3) Expanding foam with a pest-stop product (Great Stuff Pestblock foam contains a pest repellent). Avoid regular foam alone — mice can chew through it. (4) Sheet metal flashing for gaps around utility penetrations at the foundation. For the garage: install a door sweep with a metal bottom channel; standard rubber sweeps can be gnawed through.
Do ultrasonic pest repellers work on mice?
No — research consistently shows that ultrasonic pest repellers do not effectively deter or eliminate mouse infestations. Mice quickly habituate to the sound. The FTC has taken action against manufacturers making false efficacy claims. Money spent on ultrasonic devices is better spent on snap traps and exclusion materials.
When should I call a professional exterminator for mice?
Call a professional when: the infestation is large (multiple mice caught per night for more than a week), the entry points can't be located (mice are living in a wall or ceiling void with no accessible opening), or the infestation recurs after thorough exclusion work. Professional mouse control typically involves perimeter bait stations with tamper-resistant rodenticide blocks (used correctly outside — not inside walls), and a thorough exclusion audit. Cost: $200–$500 for initial treatment and exclusion recommendations.
Mice in the house: set snap traps, not poison bait. Poison bait kills mice inside walls where they decompose and attract secondary pests; snap traps produce a contained, disposable kill.
Trap aggressively on night one — setting too few traps extends the infestation.
What you need
- Victor snap traps ($10–$15 for a 6-pack)
- Peanut butter (bait — more effective than cheese)
- Steel wool for sealing
- Silicone caulk or expanding foam (to seal over steel wool)
- Flashlight (for inspection)
- Disposable gloves
Step 1: Identify the activity areas
Look for mouse droppings (small, dark, 1/4-inch pellets) along walls, behind appliances, in cabinet corners, and in drawers. Droppings indicate the main traffic areas. Also look for gnaw marks on food packaging and grease smears along baseboards.
Step 2: Set traps
Place snap traps perpendicular to walls (trigger against the wall) in every area with droppings. Set 6–12 traps on the first night — better to over-set. Bait with a pea-sized amount of peanut butter pressed firmly into the trigger.
Check traps every morning. Dispose of kills with gloves, reset with fresh bait.
Step 3: Seal entry points (begin after initial catches)
Inspect the exterior at ground level and all interior utility penetrations. Stuff steel wool into any gap larger than 1/4 inch. Apply silicone caulk over the steel wool. For larger openings around pipes: use copper mesh or metal flashing.
Continue trapping while sealing — trapping catches the current population, sealing prevents re-entry.
Step 4: Clean up attractants
Store all food (including pet food) in sealed hard plastic or glass containers. Fix any leaky pipes — mice need water daily. Clear clutter from the garage and basement that provides nesting material (cardboard boxes, paper bags).
Related guides
- How to Get Rid of Ants — spring ant control
- Annual Home Maintenance Schedule — fall pest exclusion checklist
- Identify activity areas
Look for mouse droppings (small dark pellets, 1/4 inch) along walls, behind appliances, in cabinet corners, and in drawers. Droppings indicate the main traffic routes. Also look for gnaw marks on food packaging, grease smears along baseboards, and nesting material (shredded paper, insulation) in undisturbed areas. Map all affected areas before setting traps — you'll need traps in every room with evidence.
- Set traps aggressively
Place Victor snap traps perpendicular to walls with the trigger end touching the wall — mice run along wall edges, not across open floors. Bait with a pea-sized amount of peanut butter pressed firmly into the trigger. Set 6–12 traps on the first night across all active areas. Check traps every morning, dispose of kills with gloves, and reset with fresh bait. Do not use poison bait — mice die inside walls where they decompose and attract secondary pests.
- Seal all entry points
After initial catches confirm the population size, inspect the exterior at ground level and all interior utility penetrations for holes larger than 1/4 inch (the size of a dime). Stuff steel wool tightly into all gaps — mice avoid chewing through it. Apply silicone caulk over the steel wool to hold it in place. For larger openings around pipes: use copper mesh (Stuf-fit) or metal flashing. Install a metal-bottom door sweep on the garage door if needed. Continue trapping while sealing — trapping removes the current population while sealing prevents re-entry.
- Remove food and harborage
Store all food (including pet food and bird seed) in sealed hard plastic or glass containers — cardboard boxes and paper bags are not mouse-proof. Fix any leaking pipes — mice need daily water access. Clear cardboard boxes, paper bags, and insulation from storage areas that provide nesting material. Move firewood away from the house exterior. Mice don't need much: food, water, and shelter within a small territory.
Free: 10-Point Home Maintenance Checklist
Prevent costly repairs with this seasonal checklist. Save hundreds every year by catching problems early.
Your checklist is ready!
Open Checklist →Something went wrong. View the checklist here.