Home and Landscape

Quick Tips: Rats

For more information see Pest Notes

Rats are among the most troublesome and damaging rodents in residential areas. Rats damage garden crops and tree fruit and may infest buildings where they can contaminate food and transmit diseases to humans and pets. Manage rats by removing food and shelter, reducing entryways into buildings, and trapping.

Signs of a rat infestation:

  • Rat droppings in near food preparation areas, storage areas, or around pet food containers
  • Gnaw marks on fruit or nuts in your yard
  • Rat nests behind boxes, in garage drawers, or in woodpiles
  • Burrows beneath garbage cans and compost piles or among garden plants
  • Rats traveling along utility lines or on fence tops at dusk

Is it a Norway rat or a roof rat?

  • The stocky Norway rat builds burrows along building foundations, beneath rubbish, or in woodpiles. Indoors they tend to remain in basements or on the ground floor.
  • Roof rats are great climbers with a tail longer than their head and body. They usually live and nest above ground in shrubs, trees, or dense vegetation. Indoors they favor attic spaces, walls, false ceilings, and cabinets.

Get rid of rats by limiting access and removing food, water, and shelter.

  • Seal cracks and openings larger than 1/4 inch with steel wool, wire screen, or sheet metal. Rats can chew through plastic, foam, wood, and caulk.
  • Make sure doors, windows, and screens fit tightly. Install door sweeps or weather stripping to seal any gaps.
  • Feed pets only the amount of food they will eat at a single feeding or bring food inside at night.
  • Keep food, garbage, and garden debris in containers with tight-fitting lids.
  • Thin dense plantings and create at least a 2-foot space between each shrub as well as between shrubs and buildings.
  • Remove climbing plants from buildings and prune tree limbs that are within 3 feet of a roof.

Remove rats from the home by trapping.

  • Snap traps are the safest, most effective, and most economical way to trap rats.
  • For Norway rats, place traps close to walls, behind objects, in dark corners, and in places where you have found rat droppings.
  • For roof rats, place traps in off-the-ground locations such as ledges, shelves, branches, fences, pipes, or overhead beams.
  • Ensure traps are out of reach of children and pets.

What about pesticides?

  • Toxic baits to control rodents are formulated with an attractant (generally food) and a rodenticide (toxin). Tamper-proof, ready-to-use, bait stations are available.
  • All rodenticides are toxic to nontarget species, pets, and humans. Read and follow the label carefully and always keep them away from children and pets.
  • Minimize entry points to buildings before baiting outside to prevent poisoned rats from coming inside to die.
Adult roof rat.
Adult roof rat. Credit: Jack Kelly Clark, UC IPM
Norway rat.
Norway rat. Credit: Jack Kelly Clark, UC IPM
Norway rat burrow with entrance, nest, and escape hole.
Norway rat burrow with entrance, nest, and escape hole. Credit: Nam Nguyen
Key characteristics of Norway and roof rats.
Key characteristics of Norway and roof rats. Credit: Illustration from Bjornson, B. F., and C. V. Wright
Text Updated: 06/2024