Rat and mouse article

Rats in the Garage and Under the Hood

Updated November 4, 2026

A garage is the closest thing a Miami house has to a basement, and a parked car is a warm, sheltered spot. Here's how to spot rodents in both and keep them out.

Rodents in a Miami garage usually come from one of two places: mice slipping under a worn door seal, or roof rats coming down from the attic, since many garages share an open ceiling with it. A car that sits for days gives them a sheltered spot to nest and wiring to chew.

Here's what to look for in the garage and under the hood, how to protect a car that sits, and how to close the garage up.

Signs in the garage

Check these first:

• Droppings along walls, on shelves and on top of the water heater
• Chewed bags of pet food, bird seed or grass seed
• Shredded paper or fabric in boxes, especially holiday decorations
• Gnaw marks on the bottom corners of the garage door or the door into the house
• Rub marks along the top of walls or open ceiling joists

Signs under the hood

Pop the hood and look with a flashlight. Rodents leave nest material like leaves, paper, palm fiber or insulation tucked near the engine, on top of the battery or in the air filter box. Look for droppings on the engine cover, chewed insulation on the underside of the hood and food stashes such as seeds or fruit pits. A warning light, a car that won't start or a burning smell after the car sat can all point to chewed wiring. Take it to a mechanic and take photos for your insurer.

Why cars attract them

An engine bay is sheltered, dark and warm after a trip. A car that sits for days, like a second car or one parked while you travel, gives rodents time to settle in. Food left in the car, like snacks, fast food bags or pet food, makes it worse. Cars parked in carports or under trees are easy to reach for roof rats moving through the canopy.

Protecting a parked car

A few habits make a car less inviting:

• Use each car regularly and pop the hood now and then to check
• Keep food, wrappers and pet food out of the car
• Park away from fruit trees and palms when you can
• Keep the garage floor around the car clear of boxes and clutter
• Set snap traps along the garage walls near the car, out of reach of pets

Closing up the garage

UF/IFAS says mice can get through a 1/4-inch gap and rats through 1/2 inch. On a garage, check the door's bottom seal and corners, the side jambs, the door into the house, and every hole where the water heater, laundry lines, gas line or electrical pass through the wall. Replace a cracked bottom seal, add a sweep to the house door, and pack pipe holes with copper or stainless mesh before sealing over them.

Then look up. If the ceiling is open to the attic, or the attic hatch is in the garage, rats in the attic can drop right in. That part of the job is roofline work. See garage rodent control and rodent exclusion.

Storage that helps

Swap cardboard boxes for plastic bins with lids. Keep storage on shelves with the bottom shelf off the floor. Leave a clear strip along the walls so you can see droppings and set traps. Keep pet food, bird seed and grass seed in metal cans. A tidy garage takes away cover and makes any new activity easy to spot.

Converted garages and carports

Plenty of Miami garages aren't garages anymore. A converted garage often has a gap where the old door opening was framed in, especially at the slab. Carport storage closets are open on one side and sit right next to parked cars. Check the seams where new walls meet old ones, and the gap at the bottom of the closet door.

Cleaning up

Clean droppings and nest material the CDC way: gloves on, soak with disinfectant or a bleach solution for about five minutes, wipe up with paper towels and bag it. Don't sweep or use a shop vac, which puts dust in the air. For a heavily soiled garage or attic, see droppings cleanup and sanitizing.

Rats coming down from the attic

Many Miami garages have an open ceiling, an attic hatch or a pull-down ladder that connects to the house attic. UF/IFAS lists attics and soffits among roof rats' favorite nest sites, so the rats in your garage may live overhead and come down to eat. If you find droppings on top of the water heater, along the top of the garage walls or on stored items up high, look up. Sealing the garage door won't help if the rats come in from the roof. Trap in the attic, then seal the roofline. See attic rodent removal.

Related services: Garage Rodent Control, Rodent Exclusion, Rat Control