Rats and mice: roof rats, sealing entry points and a free county inspection
For Silicon Valley homes · Updated October 2026 · Sources below
Roof rats are common in California cities: they nest in trees, ivy and dense shrubs and get into attics and walls. Lasting control means sealing gaps over 1/4 inch, cutting off food like fallen fruit and pet food, and trapping. Santa Clara County residents can request a free exterior rodent inspection from the county's Vector Control District.
The short version
- Seal openings larger than 1/4 inch with steel wool, wire screen or sheet metal - not chicken wire
- Snap traps are the safest, most effective way to trap rats
- Most anticoagulant rat poisons are prohibited in California
- Free exterior rodent inspection from Santa Clara County Vector Control
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What it costs
- Rodent removal$189 - $656 (average $396)
Sealing entry points may be extra.
Typical ranges from published cost guides - mostly national figures. Bay Area prices usually run higher. Your actual price depends on your home and the job, and a pro gives you the real number. Source: HomeAdvisor cost guide (national) (Jun 2026). Have a quote? Check it with the Quote Explainer
Signs of rats
- Scratching or running sounds in the attic or walls, especially at night
- Droppings near food, pet food or in the attic
- Gnawed fruit or hollowed-out oranges still on the tree
- Rats running along fence tops or utility lines at dusk
- Chewed wires, insulation or stored items
What to do first
- Remove food: pick up fallen fruit and nuts, bring pet food in at night, and use bins with tight lids.
- Thin ivy, star jasmine and other climbing plants on fences and walls, and trim branches back from the roof.
- Seal entry points first, then trap inside - so rats don't get trapped in the walls.
- Call a pro when rats are in the attic or walls, or if you can't find how they're getting in.
In Silicon Valley
- Santa Clara County Vector Control District offers free exterior rodent inspections: a technician looks for entry points and attractants and advises on repairs, trapping and safe cleanup. The district doesn't trap, remove rodents or do repairs, and staff don't go on roofs or into attics or crawl spaces.
- California currently prohibits most uses of first- and second-generation anticoagulant rodenticides, with limited exemptions for agricultural sites.
- Roof rats prefer warm, coastal climates and are found in almost all California cities. They eat citrus and avocados, often while the fruit is still on the tree.
Questions homeowners ask
How do I know if I have roof rats?
Look for droppings near food or in the attic, hollowed-out citrus on the tree, gnaw marks on fruit and nuts, and rats running along fence tops or wires at dusk. Night-time scratching in the attic is a classic sign.
Does Santa Clara County do free rat inspections?
Yes. The Santa Clara County Vector Control District offers free exterior rodent inspections and advice on sealing entry points, trapping and cleanup. They don't trap or remove rats, so you'll still need to do that yourself or hire a pro.
How do I keep rats out of my attic?
Seal any crack or opening larger than 1/4 inch with steel wool, wire screen or sheet metal, and cover vents with sturdy metal mesh - rats get through chicken wire. Trim branches back from the roof and thin climbing vines on the walls.
Are traps or poison better for rats?
UC IPM calls snap traps the safest, most effective and most economical way to control rats. Poisons are toxic to pets and wildlife, and a poisoned rat can die inside your walls. Most anticoagulant poisons are now prohibited in California.
Why do I have rats in my yard?
Usually food and shelter: fallen fruit, pet food, bird seed, open compost, and dense ivy or shrubs against the house. Clearing those makes your yard much less attractive.
How much does rodent removal cost?
See the typical range from HomeAdvisor's national cost guide on this page. The total depends on how many entry points need sealing, attic cleanup and how many follow-up visits are needed, and Bay Area prices usually run higher.
Save with your neighbors
Rodent-proofing before winter is a job neighbors team up on: one pro, one trip down your street, a group price the pro sets. Three homes start it.
Start or join a Neighborhood Block DealQuestions to ask the pro
- Where are they getting in, and can you show me?
- Is sealing the entry points included, and what materials do you use?
- How many visits are included to check traps?
- Do you clean up droppings and replace damaged attic insulation?
- Do you use traps or bait, and how do you protect pets and wildlife?
Before you sign, check the contractor's license at cslb.ca.gov. How to hire a contractor in California
Need a rodent control pro?
Tell us about the job in 2 minutes - free. We send it to one local pro at a time, never a crowd.
Related answers
Sources
General information for Silicon Valley homeowners, not professional advice for your home. Rules and programs change - check the source, and have a licensed pro look at your situation.