The main signs of rats are droppings about 1/2 to 3/4 inch long, gnaw marks and rough 2-inch holes, dark greasy rub marks along walls and beams, burrows along the foundation, and scratching or gnawing in the walls, ceiling or attic at night. Rats are much bigger than mice and can squeeze through a gap the size of a quarter. To get rid of them, seal entry points with metal, remove food and water, and use large rat-size snap traps along walls and runways. Clean droppings with disinfectant, never by sweeping.
Table of Contents
Signs of Rats in Your House
- Droppings: Norway rat droppings are about 3/4 inch long and capsule-shaped with blunt ends, often in clumps. Roof rat droppings are about 1/2 inch and pointed at one end. Fresh droppings are soft, shiny and dark; old ones are dull and crumbly.
- Gnaw marks and holes: chewed wood, plastic, wiring and food packaging, and ragged holes about 2 inches across.
- Rub marks: dark, greasy smudges along walls, beams, pipes and rafters where rats travel the same route.
- Burrows: Norway rats dig holes 2 to 3 inches wide along foundations, under sheds, woodpiles, compost and garbage bins, with smooth, debris-free entrances.
- Runways and tracks: packed paths through grass and footprints or tail marks in dust. Sprinkle flour or talc along a wall to check.
- Sounds: scratching, gnawing, climbing and squeaking in walls, attics and drop ceilings, mostly at night.
- Outdoors: rats running along fences or utility lines at dusk, and hollowed-out fruit on citrus or avocado trees, a roof rat sign.
Seeing rats in daytime usually means a large population. There are almost always more rats than you see.
Norway Rat vs Roof Rat
| Norway rat | Roof rat | |
|---|---|---|
| Body | Large and stocky, 7 to 18 ounces | Sleek and slender, 5 to 12 ounces |
| Nose | Blunt | Pointed |
| Ears | Small; don’t reach the eyes when folded | Large; reach the eyes |
| Tail | Shorter than head and body | Longer than head and body |
| Fur | Coarse, brown or reddish-gray with a lighter belly | Black, gray or brown with a gray, white or cream belly |
| Droppings | About 3/4 inch, blunt ends | About 1/2 inch, pointed at one end |
| Lives | Burrows; basements and ground floors | Climbs; attics, trees, upper floors, wall voids |
| Where common | Across the U.S. | Warm and coastal areas; the main rat in Florida |
Rats vs mice
Rats are much bigger than house mice, which have a body only 2 1/2 to 3 1/2 inches long. Mouse droppings are only 1/8 to 1/4 inch, mice chew small clean holes about an inch across, and they fit through gaps about 1/4 inch wide. Mice are curious and walk into new traps; rats are cautious and avoid new objects. For mice, see signs of mice and how to get rid of them.
Why Rats Get Into Houses
Rats come in for food, water and shelter, especially in fall and winter. A rat can squeeze through an opening about 1/2 inch wide, roughly the size of a quarter. Roof rats climb trees, vines, fences and utility lines to reach roofs, soffits and attic vents, while Norway rats burrow under foundations and enter through gaps around pipes, doors and basement windows.
How fast rats breed
Norway rats have four to six litters a year with 6 to 12 young each, and the young can breed at two to three months old. Roof rats have three to five litters of five to eight young a year. A small problem can grow quickly if nothing is done.
Are Rats Dangerous?
- Leptospirosis: spread through rat urine in water, soil or food; severe cases damage the kidneys and liver.
- Rat-bite fever: spread by bites, scratches and contact with rat saliva or urine.
- Seoul virus: a hantavirus carried by Norway rats that can cause kidney disease; people catch it by breathing dust from droppings and urine.
- Food poisoning: salmonella and other bacteria from contaminated food and surfaces.
- Fire risk: rats gnaw electrical wiring.
Rats can look healthy while carrying these diseases. Common rats in homes are not a rabies risk.
How to Clean Up Rat Droppings Safely
- Open doors and windows and leave the area for 30 minutes.
- Wear rubber, latex or nitrile gloves.
- Spray droppings, urine and nesting material with a fresh bleach solution (1.5 cups bleach per gallon of water) or an EPA-registered disinfectant and let it soak 5 minutes.
- Wipe up with paper towels, double-bag everything, and disinfect the area.
- Never sweep or vacuum droppings; it stirs virus-laden dust into the air.
How to Get Rid of Rats
1. Seal entry points
- Seal any gap larger than 1/4 inch; that stops both rats and mice.
- Use hardware cloth, sheet metal, cement or lath screen. Steel wool held in place with caulk works for small holes.
- Rats chew through plastic, foam, wood and caulk alone. Never use chicken wire on vents; use 1/2-inch galvanized wire cloth or finer.
- Trim tree branches back at least 3 to 6 feet from the roof, keep shrubs 2 feet from walls, and remove ivy from the house.
2. Remove food and water
- Use garbage cans with tight lids; galvanized metal holds up better than plastic.
- Pick up fallen fruit, nuts and birdseed.
- Feed pets only what they eat at once and store pet food in sealed metal or heavy containers.
- Fix leaks and remove standing water.
3. Trap them
- Use large rat-size snap traps; mouse traps are too small. Traps with a large expanded trigger catch more.
- Place traps along walls and runways where you see droppings and rub marks, with the baited end against the wall, about 10 to 20 feet apart. A heavy problem may need a dozen or more traps.
- For roof rats, also set traps on ledges, shelves, pipes, beams and fence tops.
- Rats are wary of new objects. Bait the traps with peanut butter but leave them unset for a few days until the bait is being taken, then set them.
- Keep trapping for at least two weeks. A week with no catches and no new sign suggests the rats are gone.
- Keep traps away from children and pets, or put them in a box or station.
4. Skip these
- Glue traps: the CDC advises against them because trapped rats urinate in panic, and rats often pull free.
- Ultrasonic devices: rats get used to the sound and established rats don’t leave.
- Poison inside the house: poisoned rats often die inside walls, causing a strong smell and drawing flies and beetles.
5. Use bait stations only with care
Under EPA rules, rat poison sold to homeowners must come in tamper-resistant bait stations with block or paste bait; loose pellets and the strongest anticoagulants are for professionals only. All rodenticides are poisonous to pets and wildlife, and dogs are the most common victims, sometimes from eating poisoned rats. Seal entry points before baiting so rats don’t die inside.
6. Call a professional
Call a licensed pest control company if trapping and sealing don’t solve the problem, if rats are traveling on utility lines or nesting in walls and attics you can’t reach, or if you find burrows around the whole foundation.
Rat control supplies
- Large rat snap traps for walls and runways
- 1/4-inch hardware cloth for vents and gaps
- Copper or steel mesh for small holes
- Galvanized trash cans with tight lids
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FAQs
Droppings about 1/2 to 3/4 inch long, gnaw marks and rough holes about 2 inches wide, dark greasy rub marks along walls and beams, burrows along the foundation, tracks in dust, and scratching or gnawing sounds in walls, ceilings or the attic at night.
Rat droppings are much bigger: Norway rat droppings are about 3/4 inch with blunt ends, roof rat droppings about 1/2 inch with a pointed end. Mouse droppings are only 1/8 to 1/4 inch, about the size of a grain of rice.
Norway rats are larger and stockier, with a blunt nose, small ears and a tail shorter than the body; they burrow and live in basements and ground floors. Roof rats are sleeker, with a pointed nose, large ears and a tail longer than the body; they climb and live in attics, trees and upper floors.
About 1/2 inch, roughly the size of a quarter. Sealing every gap larger than 1/4 inch keeps out both rats and mice.
Seal entry points with metal or hardware cloth, remove food and water, and use large rat-size snap traps along walls and runways. Leave traps baited but unset for a few days so wary rats get used to them, then set them and keep trapping for at least two weeks.
They can be. Rats spread leptospirosis, rat-bite fever, salmonella and Seoul hantavirus through urine, droppings, saliva and bites, and their gnawing on wires can start fires. Clean droppings with disinfectant, never by sweeping or vacuuming.
Sources
- UC IPM Pest Notes: Rats
- University of Kentucky: Rodent Control
- University of Florida IFAS: Roof Rats
- Internet Center for Wildlife Damage Management: Norway Rats
- CDC: How to Trap Up to Control Rodents
- CDC: How to Clean Up After Rodents
- CDC: About Leptospirosis
- U.S. EPA: Restrictions on Rodenticide Products
Facts in this guide are checked against the sources above and reviewed when they change. See how we research in our editorial policy.
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- Roof Rats vs Norway Rats (and Rats vs Mice): How to Tell Them Apart
- Signs of Mice in Your House & How to Get Rid of Them
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- Pantry Moths (Indian Meal Moths): How to Get Rid of Them for Good
- Carpet Beetles: Larvae, Damage, Rash & How to Get Rid of Them