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Where Are Mice Coming From? (A Tour of Your House's Secret Doors)
You keep a clean house. The doors are shut. And yet: mouse. So where are they coming from? Somewhere small — very small.
Quick answer: Most mice come in from outside through gaps of ¼ inch or more — garage doors, gaps around pipes and wires, the foundation and sill plate, vents and the roofline — usually in fall when it gets cold. Fresh droppings and grease marks along walls point you toward the door they use.
The top mouse doors in New Jersey homes
| Entry point | What to look for |
|---|---|
| Garage door | Worn rubber seal, gaps at the bottom corners |
| Pipes, gas lines, AC lines | Gaps where they go through the wall — classic route (see sealing materials) |
| Foundation & sill plate | Cracks and gaps where the house sits on the foundation |
| Doors | Missing or worn door sweeps |
| Vents | Dryer vents with broken flaps, crawl space vents |
| Roofline | Gaps at roof corners and soffits — mice climb, see mice in the attic |
| Things you carry in | Boxes, firewood, bags of bird seed from the garage |
How to find their door
- Follow the droppings — they get thicker near entry points and nests.
- Look for dark grease rub marks along baseboards and pipes.
- Check under sinks and behind the stove where pipes enter.
- Do the pencil test outside: if a pencil fits in a gap, so does a mouse.
Then close the door: what keeps mice out of your house · mouse fun facts
Watch: Silver Bullet mice & rat work
Can’t find how they get in? Silver Bullet Pest Control handles mouse control and rodent exclusion across Bergen, Passaic and Essex counties. Call 973-510-2585, text us, or request a free quote.
What to look for
More about mice
- 20 Fun Facts About Mice
- Does Irish Spring Soap Keep Mice Away??
- What's the Best Mouse Trap Bait??
- Does One Mouse Mean More??
- All pest questions, answered
Fun facts about other pests
- 21 Fun Facts About Ants
- 20 Fun Facts About Squirrels
- 20 Fun Facts About Bees and Wasps
- 18 Fun Facts About Rats
- 18 Fun Facts About Cockroaches
- Waterbug vs. Cockroach: Fun Facts
Common questions
Where do mice come from in a house?
From outside, through small gaps in the garage, foundation, around pipes and wires, vents and the roofline.
Why do I have mice all of a sudden?
Cold weather in fall pushes mice inside looking for warmth and food.
How do mice get into a clean house?
Cleanliness doesn’t matter if there’s a gap — they come in for shelter and warmth, not just food.
How do I find where mice are getting in?
Follow droppings and grease marks, check where pipes enter walls, and look for gaps of ¼ inch or more outside.
Schedule today
Call 973-510-2585, text us or request a free quote online. Silver Bullet Pest Control is licensed and insured in New Jersey.