WebLock Pest Control
·5 min read

Why Mice Come Inside in Fall (and How to Stop Them)

Pennsylvania mice need only a 1/4-inch gap and a warm hint. Here's why fall is rodent season and what to seal first.

Mice aren't trying to ruin your fall

They're just cold and hungry. A Pennsylvania mouse can squeeze through a hole the diameter of a pencil. Once the nighttime temperature drops below about 55°F (usually mid-September here in Bucks County and Northeast Philly), they go looking for somewhere warm. Your house is the easiest option in their neighborhood.

The four favorite mouse entry points

1. Where utility lines enter

Cable, gas, electrical, AC line set. The hole around the line is almost always larger than the line itself. Seal with copper mesh + foam.

2. Under garage doors

Even a 1/4-inch gap at the side or bottom corner is enough. Replace torn weatherstripping.

3. Dryer vents

Damaged louvres are a wide-open door. Buy a $15 pest-proof vent cover.

4. Where the foundation meets the siding

Look for daylight showing through when you're in the basement at night. Foam, then trim, then paint.

What works, what doesn't

Works:

  • Snap traps placed perpendicular to walls (mice run along walls, not across rooms)
  • Sealing every entry point you can find
  • Removing food sources (open dog food bags, fruit on counters, pet bowls left out overnight)

Doesn't really work:

  • Ultrasonic plug-in repellers (mice get used to them in days)
  • Cat hair / peppermint oil / dryer sheets (mostly internet folklore)
  • One or two traps in the basement (mice nest in walls, not basements — set traps where you see droppings)

When to call us

If you've been hearing scratching in the walls or ceiling for more than a week, you have an active infestation that's growing. Mice can have 5–10 litters per year. A pair of mice in October becomes 30+ mice by spring.

Our rodent service starts with full-home exclusion — we seal every entry point larger than a dime — then sets traps in the right spots. Most homes are clear within 2 weeks.

We serve Levittown, Bensalem, Warminster, and every other town in Bucks County and Northeast Philly.

Need a real exterminator, not just an article?

Free inspection, family-owned, all of Bucks County + NE Philly.

Call 445-900-4999