How to Get Rid of Rats: Norway Rats and Roof Rats

Something heavy is running across the ceiling at night, or there is a hole a few inches wide under the back steps. Rats are a bigger job than mice. They are wary of new things, they travel farther for food and an adult can get through a 1/2-inch gap. This guide helps you figure out which rat you have, why it is on your property and how to trap it and keep it out.

How to identify Norway rats and roof rats

Two non-native rats cause almost all the trouble in US homes. Which one you have decides where you set traps and which gaps you seal.

Roof rats prefer warm climates: the southern East Coast, the Gulf states, the Pacific Coast and Hawaii. Most interior states have only Norway rats. If the animal is small, look at the head and feet. Young rats have big heads and feet for their size; mice do not. For mice, see our mouse guide.

Signs of rats

• Droppings in small clumps along walls and near food.
• Burrows 2 to 3 inches wide along foundations, fences, under bushes and under compost piles or garbage cans. An active burrow has a clean, smooth entrance.
• Runways: worn paths in grass or along fences that rats use night after night.
• Rub marks: dark, greasy smears on walls, beams and pipes along their routes.
• Gnaw marks about 1/16 inch wide, roughly twice the width of mouse marks.
• Noises in the attic or drop ceiling at night.
• Sightings of rats running along utility lines or fence tops at dusk.

Our signs of rodents guide covers how to tell fresh signs from old ones.

How rats behave, and why it matters

Rats are mostly active at night. They have a sharp sense of smell, taste and touch, and they stick to the same routes.

They are also suspicious of anything new, a trait called neophobia. A rat may walk around a new trap or bait for days or even weeks. Roof rats are thought to be even warier than Norway rats. This is why a trap that catches a mouse the first night may sit untouched by a rat. The fix is pre-baiting, covered below.

Rats also forage widely. A Norway rat may cover 100 to 500 feet a night, and a roof rat may go 300 feet or more for food. The food source may be in a neighbor’s yard.

Why rats show up in yards

Rats come for food, water and cover. Common draws:

• Pet food left out overnight, and pet waste.
• Fallen fruit and nuts under backyard trees.
• Bird feeders and spilled seed. Keep feeders away from the house and clean up under them.
• Compost and garbage in open piles or bins without tight lids.
• Dense ivy and vines on fences and walls, which roof rats nest in.
• Woodpiles and clutter that give Norway rats a place to burrow.

Rats in the attic: roof rats

Roof rats climb well and use overhead routes. They run along utility lines and fence tops and travel through tree branches onto the roof. From there they find a gap at the eaves, a broken vent screen or a hole around a roof pipe. To cut off these routes:

• Trim tree limbs so none hang within 6 feet of the roof.
• Thin or remove ivy, jasmine and other climbing vines on walls and fences.
• Close gaps at the roof line, not just at ground level. This takes longer than sealing for Norway rats.

Trimming limbs also keeps squirrels off the roof. If you suspect squirrels instead, see our squirrel guide.

How to get rid of rats, step by step

1. Find out which rat you have using the table and signs above.
2. Remove food and cover. Bring in pet food at night, pick up fallen fruit, use tight lids on garbage and rigid compost bins, and clear clutter.
3. Seal entry points (see below).
4. Pre-bait and trap.
5. Clean up droppings and nests safely, as covered in the rodent hub.

How to trap rats

Snap traps are the safest, most effective and cheapest way to kill rats. Buy traps made for rats, not mouse traps.

Pre-bait first. Put baited traps out unset and leave them for several days, until rats take the bait readily. If the bait is gone from every trap, add more traps. Then set them all on the same night.

• Bait: a pea-sized amount of nuts, dried fruit, bacon, pet food or peanut butter.
• Placement for Norway rats: along walls, with the trap at a right angle to the wall and the trigger end nearly touching it. If you must set traps parallel to a wall, use pairs facing opposite directions.
• Placement for roof rats: set traps both on the ground and up high, on ledges, fence tops, pipes and beams. Fasten them down so they do not fall.
• How many: space traps about 10 to 20 feet apart. A home with a heavy infestation may need a dozen or more.
• Safety: snap traps can hurt fingers and paws. Set them inside a box or behind a barrier where children and pets cannot reach.

Electronic traps also work on rats but cost more and need pre-baiting too. Glue boards are not a good choice: rats often pull free, and the UC IPM program does not recommend them for homeowners or ever outdoors. Live trapping rats is not recommended, and releasing them is discouraged. Ultrasonic devices do not work; rats get used to the sound.

How to rat-proof your house

Seal every opening larger than about 1/4 inch, since young rats get through gaps that size and adults get through 1/2 inch. Rats chew through plastic, foam, wood and caulk, so use:

• Steel wool or copper mesh packed in small gaps, covered with caulk.
• Hardware cloth (heavy galvanized wire mesh) over vents and larger holes. Lightweight chicken wire does not stop rats.
• Sheet metal around pipe holes and on gnawed door edges.
• Concrete or mortar for foundation cracks and around utility lines.
• Door sweeps or weather stripping so no door has a gap of more than 1/4 inch at the bottom.

Our rodent-proofing guide walks through a full inspection and lists materials by gauge.

Bait stations and the risk to pets and wildlife

If you use rat bait, federal rules mean consumer products come only as blocks or paste in a ready-to-use bait station. Use tamper-resistant stations anywhere children, pets or wildlife could reach. Place them along runways or near burrows, secure them for roof rats, and read and follow the label. Pick up leftover bait when you are done. Some states, including California, restrict the anticoagulant baits sold elsewhere, so check your state’s rules.

All rat baits are toxic to dogs and cats. There is a second risk most people do not think about: poisoning of pets and wildlife that eat poisoned rats. Anticoagulant baits build up in a rat’s body, so one dead or dying rat can hold enough poison to harm a dog, cat, owl or hawk that eats it. Keep pets away from dead and dying rats, and collect carcasses with gloves. For a full comparison, see traps vs. bait stations.

When to call a professional

Rats are more often a job for a pro than mice. Get help if:

• Roof rats are in the attic and the entry points are along the roof line or eaves.
• Norway rats are burrowing under a slab, porch or foundation.
• You have pre-baited and trapped for a few weeks and still see fresh signs.
• You need rodenticide at a level that calls for professional products and handling.

Ask what the provider will do about entry points, how they handle carcasses and whether they use traps, bait or both. Our guide to choosing a pest control company can help.