When Rodents Move In: How to Keep Unwanted Winter Guests Out
Nov 14, 2025, 15:32 PM
by
Fred Speer
Clark Pest Control | Last Updated: January 15, 2026
Key Takeaways
- Cooling triggers migration. Sacramento’s distinct temperature drop in autumn drives mice and rats indoors seeking warmth.
- Hidden dangers. Rodents chew through electrical wiring (fire hazard) and contaminate food surfaces with bacteria.
- Exclusion is key. Sealing entry points like foundation cracks and attic vents is the only long-term solution.
Quick Answer: As the weather cools across the Central Valley, rodents stop foraging outdoors and start looking for shelter. Your home provides the warmth and food they need. In Sacramento, House Mice and Roof Rats frequently exploit small gaps in foundations, garage doors, and rooflines to establish nests before winter hits.
Visual ID Guide: The Sacramento Invaders
While many pests exist, two specific rodents pressure Sacramento homes most during cooling weather.
_2766.jpg.jpg?sfvrsn=89908d0d_7)
Photo: Ahunt /
CC0 1.0
1. House Mouse
Target: Kitchens, wall voids, pantries.
Risk: HIGH. Can squeeze through a hole the size of a dime. Rapid breeders (up to 35 offspring/year).
Photo: CSIRO /
CC BY 3.0
2. Roof Rat (Black Rat)
Target: Attics, rooflines, garages.
Risk: HIGH. Agile climbers that use trees and power lines to access roof vents. Need a gap the size of a quarter.
Where They Sneak In
Rodents are opportunists. In the Sacramento area, they frequently take advantage of gaps around garage doors, foundation cracks, vents, and utility lines. Even overgrown shrubs or stacked firewood can serve as convenient "bridges" to your home.
Common Entry Points Include:
- Garage Door Seals: Worn rubber strips allow easy ground-level access.
- Attic Vents: Unscreened vents are an open door for Roof Rats.
- Utility Penetrations: Gaps where pipes or wires enter the siding.
- Foundation Cracks: Common in settling Valley homes.
Clark's Expert Insight
"In Sacramento, we often see homeowners waiting until they hear scratching to call us. By then, the nest is established. The best time to act is when you first feel that autumn chill—before they move in."
What’s at Risk?
Rodents may be small, but their impact is anything but.
Property Damage: They chew through drywall, insulation, and electrical wiring. This gnawing behavior creates legitimate fire hazards and necessitates costly repairs.
Health Hazards: They contaminate food and surfaces, spreading bacteria and diseases such as Hantavirus and Salmonella that threaten your family’s health.
Smart Ways to Keep Rodents Out
You don’t need to wait for signs of activity to take action. Proactive prevention makes all the difference.
- Seal it tight: Inspect foundation and rooflines. Close gaps with steel wool or metal flashing.
- Trim it back: Keep trees and shrubs at least a few feet from the house to remove access bridges.
- Store smart: Keep firewood 20 feet from your home and elevated.
- Declutter: Keep storage areas neat and items off the floor to eliminate hiding spots.
- Keep it clean: Seal food in airtight containers and wipe up spills immediately.
Watch: Smart Ways to Keep Rodents Out
Video: Simple steps to rodent-proof your home.
Frequently Asked Questions (FAQs)
Why do I have mice when it gets cold? ▶
Mice are warm-blooded mammals that seek shelter to survive the temperature drops in Sacramento's autumn and winter seasons. Your home radiates heat and offers food, making it the perfect target.
How do I know if I need professional exclusion? ▶
If you hear scratching in the walls at night, find droppings in cupboards, or see gnaw marks on food packaging, you likely have an active issue. Professional exclusion is the only way to ensure all entry points are sealed.
What is Clark’s Exclusion Shield? ▶
Exclusion Shield is our year-round protection service. It includes sealing entry points, ongoing repair coverage at no extra charge, trapping/remediation, and routine inspections to stop rodents before they start.
Serving California and Northern Nevada
Our licensed pest control experts know exactly where to look for rodent entry points and hidden nests.
Don't Let Them Move In This Winter
Rodent infestations can escalate quickly in cooling weather. If you see droppings or hear scratching, Clark Pest Control can confirm the species and recommend the right exclusion plan.
Call 1-800-882-0374