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7 Signs of Rats in the House and What to Do

How to Identify and Control Rat Infestations at Home

How to Identify a Rat Infestation in Your Home

The Spruce / Michela Buttignol

You can tell if you have rats in the house by seeing signs like gnaw marks, food crumbs, and droppings. The two most common rats, Norway and roof rats, are equally destructive and can carry diseases. Here, learn the signs of a rat infestation and how to identify and control these pests in your home.

Signs of Rats in the House

Because rats are nocturnal and are most active at night, an infestation can develop before a rodent is ever seen. So it is best to keep an eye—and an ear—out for signs of rodent presence

  1. Live or Dead Rat Sightings

    Seeing live or dead rats is a sign of an infestation. If you see them during the day, it indicates a large infestation since they prefer to be nocturnal. Dead rats can be a sign of rat poison traps nearby.

  2. Rat Droppings and Odor

    Rat droppings are roughly the size of a grain of rice. You'll likely find higher concentrations of droppings near a food source. They leave behind a telltale musky odor. Rat droppings can also carry disease, so wear gloves and a face mask when cleaning rat droppings.

  3. Scratching Noises at Night

    Scratching or scurrying sounds from your walls or attic are another indicator as they move around at night. You may also hear rustling in a pantry or gnawing on wood or wires.

  4. Nesting Materials in Hidden Spots

    Rats make nests behind appliances, in attics, basements, or empty boxes. They make them from debris like cotton, twigs, fabric, cardboard, and packing peanuts.

  5. Gnaw Marks on Wires or Wood

    Rats need to gnaw to grind down their teeth that keep growing. They often chew on electrical wires, structural wood, and drywall.

  6. Burrows in Yard

    Rats make burrows in the yard, usually with a primary hole with two secondary exits. Rat burrows can be under the home or outbuildings, especially if there is a fruit or vegetable garden.

  7. Smudge Marks

    Smudge marks and rat hairs can be found along walls and trails, marking their pathways.

Problems With Rat Infestations

Norway rats dig burrows in which to live. These can cause problems to the stability of homes and buildings when the rats dig beneath them; they also can block sewer lines and spoil the landscaping of yards.

As climbers, roof rats are most likely to cause structural damage in homes when they chew on wood and wires. They also will climb fruit trees and feed on the fruit.

Control and Prevention

The best control of any rodent is prevention focused on sanitation and exclusion. In most cases, a rat will enter a home because it is looking for food, water, or shelter.

  • Setting humane traps: The most humane rat traps are snap and live catch traps. Snap traps kill them instantly. Refrain from using glue traps or poison, which are more painful and can kill other animals besides rats.
  • Sanitation: To reduce the availability of food and water, employ sanitation methods such as covering or packaging all foods; keeping all food and food-preparation areas swept, mopped, and wiped clean; keeping trash areas clean; and removing or limiting access to fresh water.
  • Seal entry areas: To prevent rats seeking shelter from entering your home, seal up holes around the home perimeter to prevent rat entry.
  • Calling a professional pest service: Professional pest control services complete an assessment, fumigate, set, and clear traps. They can maintain a regular schedule of extermination until the situation is handled.

How to Identify Rat Species

While Norway and roof rats are very similar and can be difficult to distinguish on sight, the rats have some distinctive traits that provide evidence for identification. They are sometimes mistaken for mice, although rats are significantly larger, and their signs are distinctly different.

The Norway Rat (Rattus Norvegicus)

  • Body: Large and bulky
  • Fur: Coarse, brown 
  • Belly color: Gray to grayish, with a brown underbelly
  • Weight: 7 to 18 ounces
  • Length: About 16 inches long
  • Tail: Scaly and shorter than the length of the head and body combined
  • Ears: Small with no fur
  • Location: Found across the United States
  • Droppings: 1/2-inch long
  • Fun fact: The Norway rat is not really from Norway; they are believed to have originated in China.

The Roof Rat (Rattus Rattus)

  • Body: Sleek and slimmer than the Norway rat
  • Fur: Light black to black 
  • Belly color: Off-white to gray
  • Weight: 3 to 9 ounces
  • Length: 13 to 18 inches long
  • Tail: Hairless and longer than the combined length of its head and body
  • Ears: Ears and eyes are larger than those of the Norway rat
  • Location: Found primarily in the southeastern states and western coastal regions
  • Droppings: 1/4 to 1/2-inch long
  • Fun fact: Roof rats are often found high in trees and homes: thus its name.
FAQ
  • What causes rats to come in your house?

    Rats enter a home when they need a food source or shelter, usually at the height of the winter.

  • How do I stop rats from coming inside?

    The best way to keep rats from getting in your home is to seal up all holes around your home foundation. Fill small holes with steel wool. Use lath screen or lath metal, metal sheeting, cement, or hardware cloth to close larger gaps.

  • What will make rats go away?

    Remove all food sources and place traps to catch them. Deterrents that might make them think twice about entering your home include strong smells like ammonia, bleach, peppermint, eucalyptus, and geranium oil. Lay down the offending scents along pathways and places where the droppings have been found.

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. How to Control Wild Rodent Infestations. Centers for Disease Control.

  2. Controlling Rats. Missouri University Extension.