If you suspect rats in your attic, treat it as a job for a licensed pro, not a weekend project. In Los Angeles the usual culprit is the roof rat, a climber that nests up high, travels along wires, fences and tree branches, and is most active at night.
How to confirm it's rats
- Sounds after dark. Scurrying, scratching or gnawing overhead once the house goes quiet. More on reading the sounds in our guide to noises in the attic at night.
- Droppings. Rat droppings are about half an inch long with blunt ends. Mouse droppings are smaller, about a quarter of an inch, and pointed. Check near the attic hatch, along beams and in the garage.
- Gnawed fruit in the yard. Half-eaten oranges or avocados still on the tree are a classic roof rat sign.
- Grease marks along beams, pipes or the top of a fence where rodents run the same route every night.
- Chewed wiring, ducts or insulation, or chewed wires under a car hood.
- A way up. Palms, ivy and branches touching the roof, and damaged vent screens along the roofline.
Not sure which rodent you have? See roof rats vs Norway rats.
Why you shouldn't wait
- Chewed wiring is a fire risk, and rodents gnaw constantly to keep their teeth worn down.
- Droppings and urine soak into insulation, which spreads the mess and the smell.
- They keep breeding. Roof rats breed all year in Southern California, and many move into homes from late summer through fall, then nest in attics through the winter rains.
What not to do
- Don't rely on poison. A poisoned rat often dies inside a wall or ceiling where you can't reach it, and most anticoagulant rat poisons are now banned for home use in California. See the California rat poison ban.
- Don't just seal the hole you can see. Rats already inside will chew a new way out, and a home usually has more than one way in.
- Don't sweep or vacuum droppings dry. Wet them with a disinfectant first, wear gloves, and stay out of an attic full of droppings without protection.
How a proper fix works
- Inspection. A technician checks the roofline, attic, vents and crawlspace and photographs every entry point. Our rodent inspection ends with a written plan before any work starts.
- Removal. The rats inside are removed so none are sealed in.
- Exclusion. Every entry point is closed so they can't return. See rodent exclusion.
- Cleanup. Contaminated insulation and droppings are dealt with last. See attic cleanup.
Get it looked at
Describe what you're hearing or seeing and we'll connect you with a state-registered pest control company that serves Los Angeles County. Start with rat removal, or call the number at the top of the page.
More guides
- A dead rat smell in the wall: what to do
- How rats get into your house, and where to look
- Rats chewing your car wires: what's going on
This guide is general information, not a substitute for an on-site inspection. SealWell is a referral service, not a contractor.
