Welcome, new homeowners! You’ve just landed yourselves in some of the most beautiful spots in Marin and Sonoma counties. Think rolling vineyards, stunning coastlines, and a vibe that's just, well, different. Getting the keys to your new home is a huge milestone, a fresh start. And honestly? It should be nothing but exciting.

But let's be real. There's one uninvited guest no one wants to find settling in: rodents. And here in Marin and Sonoma? They're a persistent challenge. Our mild climate, plus all that gorgeous open space – those vineyards, hillsides, and natural habitats – means year-round rodent activity. We’re talking roof rats, Norway rats, house mice, and deer mice. Local vector control and UC guidance note roof rats along the coast, burrowing Norway rats, and commensal mice commonly in and around homes.

So, what's the goal here? Simple. We want to give you a comprehensive, actionable checklist. Think of it as your guide to proactively preventing rodent infestations, safeguarding health, and protecting your hard-earned property. Prevention is consistently more effective and less costly than addressing an entrenched infestation.

Understanding the Rodent Threat in Marin & Sonoma: Local Context and Risks

Common Rodent Species in Our Neck of the Woods:

Roof Rats (Rattus rattus): Agile climbers often found in attics, rooflines, and trees; they thrive in warm, coastal areas.
Norway Rats (Rattus norvegicus): Larger burrowers commonly active around foundations, woodpiles, and sewers.
House Mice (Mus musculus): Small, nocturnal, and adaptable; frequently in wall voids, attics, and garages.
Deer Mice (Peromyscus maniculatus): More common in rural/semi-rural settings; important carriers of hantavirus in California.

Why Your Home is Attractive to Rodents:

Rodents seek shelter, food, water, and nesting material. Urbanization along wildland edges, agriculture (including vineyards), fallen fruit/nuts, accessible feed, and structural gaps provide abundant resources and entry points year-round.

Signs of an Infestation: What to Look For (And Listen For!)

Droppings: Small, dark, pellet-like; mouse droppings are rice-sized, rat droppings larger and capsule-shaped.
Gnaw Marks: On wood, plastic, wires, baseboards, or packaging.
Noises: Scratching/scurrying in walls, attics, or crawl spaces especially at night.
Runways/Rub Marks: Dark, greasy trails along walls and pipes on frequently traveled paths.
Nests: Shredded paper, fabric, or insulation in hidden areas.
Odors: Musky, stale smells suggesting urine.
Agitated Pets: Sudden interest in certain walls/cabinets may indicate activity

The Risks of a Rodent Infestation: More Than Just a Nuisance

Health Hazards

Rodents can contaminate food/surfaces and spread pathogens (e.g., Salmonella, Leptospira, murine typhus via fleas) and, rarely, plague in wild rodent populations notably in California’s outdoors. Deer mice are the key reservoir for hantavirus, which can cause severe illness. Recent California reports (2025) documented fatal hantavirus cases, underscoring the risk where deer mice are present.

Droppings/dander may aggravate allergies/asthma, and rodents may carry fleas, ticks, and mites into living spaces.

Property Damage

Rodents chew electrical wiring (fire hazard), insulation (reducing energy efficiency), pipes/structural elements, and stored items. Local impacts are real: a Novato supermarket temporarily closed in 2023 due to a rodent infestation; Golden Gate Village in Marin City has documented pest problems over the years.

The Comprehensive Rodent Prevention Checklist for New Homeowners

This checklist centers on Integrated Pest Management (IPM), prioritizing prevention, physical controls, and careful, lawful use of chemicals only when necessary.

A. Phase 1: Exterior Fortification – Sealing Entry Points

Reality check: Mice can enter through ¼-inch gaps (about a pencil width). Rats can enter through ½-inch gaps. A thorough exterior inspection is essential.

Your Inspection Checklist – Where to Look (and What to Fix!):

Foundation & Walls:
• Seal cracks, gaps, and joints where materials meet.
• Pay special attention around utility penetrations (pipes, conduits, HVAC lines).
• Inspect voids under/around porches and sheds.Doors & Windows:
• Ensure exterior doors (including garage) seal tightly; no light visible beneath/around edges.
• Install/repair door sweeps and weatherstripping; ensure tight thresholds.
• Inspect window frames/sills/screens and secure attic hatches.

Doors & Windows:
• Ensure exterior doors (including garage) seal tightly; no light visible beneath/around edges.
• Install/repair door sweeps and weatherstripping; ensure tight thresholds.
• Inspect window frames/sills/screens and secure attic hatches.

Vents & Chimneys:
• Fit all vents (dryer, attic, foundation, roof, crawl space) with ¼-inch hardware cloth; use robust metal screens—avoid plastic.
• Verify chimneys have intact caps.

Roofline & Soffits:
• Seal gaps at eaves and damaged soffits. If daylight is visible from the attic, it’s an opening.
• Trim tree limbs back; keep limbs ~3 feet from rooflines to reduce overhead access.

Recommended Sealing Materials: What Works Best?

Small gaps (< ½ inch):
• Steel wool or copper mesh packed tightly, then sealed with caulk; foam alone is not rodent-proof.
• Use high-quality sealants to finish edges and prevent air/odor leaks.

Larger holes (≥ ½ inch):
• ¼-inch hardware cloth (16–19 gauge), cut to size and fastened securely; consider sheet metal or mortar for foundations.
• Replace damaged screens; maintain tight-fitting door sweeps and weatherstripping.

B. Phase 2: Eliminating Attractants – Inside Your Home

Reducing access to food, water, and shelter makes prevention work.

Food Storage:
• Store dry goods (including pet food and birdseed) in thick plastic/metal/glass containers with tight lids.
• Don’t leave food out overnight; remove pet food/water bowls after meals.

Kitchen & Household Cleanliness:
• Clean crumbs/spills promptly; wash dishes promptly; wipe counters daily.

Waste Management:
• Use cans with tight lids; empty regularly; clean bins with soap/water to reduce odors.

Reduce Clutter:
• Minimize piles in storage areas; keep items off floors and away from walls to reduce nesting cover and improve inspection access.

Moisture Control:
• Repair leaks and drips quickly; keep basements/crawl spaces dry and ventilated; address AC condensate and other standing water.

C. Phase 3: Landscape & Yard Maintenance – Creating a Rodent-Hostile Perimeter

Vegetation Management:
• Trim trees/shrubs so limbs don’t contact roofs; roof rats readily use vegetation as overhead highways.

Clear Debris & Storage:
• Remove leaf piles and organic debris; avoid accumulating appliances or furniture near the home.
• Stack firewood at least 18 inches off the ground and away from buildings to reduce harborage.

Gardens & Bird Feeders:
• Harvest fruits/vegetables promptly; remove fallen produce.
• Use rodent-resistant compost bins.
• Bird feeding can scatter seed clean the ground below feeders; spilled seed can attract rodents.

Outdoor Waste Management:
• Use lidded, sturdy bins (metal or thick plastic); place on hard surfaces away from structures.

Water Sources:
• Fix leaky faucets/irrigation; eliminate standing water (buckets, clogged gutters, low spots).

Inspect Outdoor Structures:
• Seal gaps in sheds/dog houses; screen openings under decks or around spas.

What If You Find Rodents? Immediate Steps and Professional Assistance

Confirm an Infestation:
Look for multiple signs (droppings, gnaw marks, noises); persistent activity indicates an established problem.

Safe Cleanup:
• Wear gloves and a mask.
• Do not sweep or vacuum droppings/urine; this can aerosolize pathogens.
• Disinfect first: spray with a 1:9 bleach solution (1.5 cups bleach per gallon of water) or an EPA-registered disinfectant; let soak 5 minutes, then wipe up; double-bag waste. Ventilate enclosed spaces as recommended.

When to Call a Professional:
• Persistent activity or extensive damage; difficulty locating entry points; health concerns (e.g., possible hantavirus).
• The Marin/Sonoma Mosquito & Vector Control District offers free rodent inspections, species identification, and recommendations; note they do not trap, poison, remove rodents, or perform exclusion.

That’s where professional services come in. If you prefer expert help from the outset or your DIY efforts haven’t solved the problem, choose a licensed provider that emphasizes exclusion, sanitation, and trapping and understands California’s rodenticide restrictions.

Ongoing Vigilance and Community Effort

Make it Routine:
Inspect monthly and before cooler seasons when rodents seek warmth indoors; address new gaps or attractants quickly.

Seasonal Awareness:
Colder months can drive rodents inside; increase monitoring accordingly.

Community Involvement:
Rodents don’t respect property lines. Coordinate prevention with neighbors, and leverage resources from the Marin/Sonoma Mosquito & Vector Control District (education, talks, literature).

Stay Informed:
Keep current on local trends and regulatory changes (e.g., California rodenticide restrictions) to ensure your approach remains effective and compliant.

Conclusion: Protecting Your Investment and Peace of Mind

Settling into your new home in Marin or Sonoma should be a joy, not a struggle with unwanted guests. By following this IPM-based prevention checklist, you substantially reduce infestation risk while protecting your family’s health and your property. If issues persist or you simply want a comprehensive, long-term solution, seek qualified professional assistance to identify and address potential entry points.