Rodents are a public health risk because they spread disease, including:

Rats can get in your home through spaces in roof or crawl spaces. They also:

  • Climb, jump and swim. If a squirrel can climb it, a rat can climb it.
  • Chew through plastic, wood, soft metals, electrical wires (sometimes causing fires) and even cinder block and brick.
  • Eat everything, including bird feed and food in your home.
  • Squeeze into tiny spaces and nest where it's dark and warm. They can produce a litter of pups (babies) every 3 to 4 weeks!

rat droppings

How do you know if you have a rodent problem?

Droppings are typically the easiest way to identify a rodent problem. Mouse droppings are smaller, like black grains of rice.

You might also see rats, hear rat squeaking, hissing or chattering noises, or find chewed up material. Outside there may be burrows or runways.

What activities increase my risk of exposure to diseases carried by rodents?

Entering or cleaning buildings that have been closed for a long period of time, such as hunting shacks, garages, storage sheds, or anywhere with rodent droppings. You can also get sick by:

  • Breathing dust that is contaminated with urine or droppings.
  • Direct contact with an infected rodent, including a rat bite.
  • Eating or drinking products contaminated with urine or feces.

rats dangling from a birdfeeder
Photo: lovecatz, Flickr

How to Get Rid of Rodents

Step 1: Take Away Their Food

Rodents will eat anything. You must get rid of their food to get rid of them. Common food sources include:

  • Bird food/feeders
  • Pet food/chicken feed
  • Garbage
  • Pet waste
  • Backyard compost that has not been rodent-proofed
  • Fallen fruit from trees or unharvested produce from gardens

The Portland Fruit Tree Project may be able to help you collect unharvested tree fruit.

heavy-duty rodent trap

Step 2: Eliminate Them

Trapping is the preferred method for eliminating rodents indoors and outdoors. Snap traps are inexpensive and effective. Peanut butter usually works as bait.

Set the trap in the area with the most rodent activity. Rodents tend to run along walls, so place traps next to a wall, fence line or foundation.

To keep children, pets and other animals safe from traps, use tamper-resistant bait stations.

Poisoning is not an ideal way to eliminate rodents, but is sometimes necessary. Poison is not recommended for indoor use, as rodents can die inside walls and produce odor.

Rodent poisons (rodenticides) are also harmful to animals and pets, so use carefully. Always use a secured bait station to keep poisons away from children, pets, and other animals.

steel hardware cloth

Step 3: Keep Them Out of Your House

  • Small openings in homes, buildings and sheds must be sealed to prevent rodents from entering.
  • Check for openings where pipes or wires enter the building, under eaves, and around foundations, doors and windows. Use cement, 1/4 inch steel hardware cloth (wire mesh, pictured), or steel wool and spray foam to seal openings.
  • Seal crawl spaces and attics to prevent rodent access.
  • Trim back overhanging branches around house to reduce roof rat access
  • Rodents often enter through open doors and gaps in weather stripping, unscreened windows and pet doors. Install weather stripping to limit access. Choose a self-closing pet door that’s designed to keep pests out.

Step 4: Keep Them Out of Your Yard

Don’t let your yard be a nesting zone for rodents. Rats will nest in:

  • Outdoor piles of garbage and junk.
  • Under wood piles or lumber. Stack wood piles 18 inches off the ground.
  • Under blackberry bushes, shrubs, vines and tall grasses that are not trimmed or cut back.
  • Persistent holes in your parking strip, under the sidewalk or front yard. These holes may be a sign of a broken sewer line. We recommend you contact either a private plumber or Multnomah County Vector Control for a referral to a dye test.

What can I do about rats coming from my neighbor's property?

You may want to consider first addressing your neighbor or the property owner on a personal, neighbor-to-neighbor basis. A neighborhood mediator can help you to have productive a conversation and work out peaceful solution.

Step 5: Get Professional Help

You may need to contact a pest professional if you have a bad infestation.

Although we’re not exterminators, a Multnomah County Vector Control inspector can come to assess your rat situation. We can provide you with recommendations and resources, including traps. Contact us at 503-988-3464 or vector.nuisance@multco.us.

Remember, before you call Vector Control for help with rats coming from a neighbor’s property, you MUST have evidence, such as:

  • Rat droppings
  • Burrows
  • Runways
  • Live rats

Concerns about unsafe or unsanitary conditions in an urban campsite may be reported online to the City of Portland»

Step 6: Clean Up After an Infestation

Follow these procedures to reduce your risk of exposure. These are recommendations provided by the Centers for Disease Control and Prevention.

Remember that bleach can stain surfaces and that cleaning chemicals can be harmful if misused. ALWAYS follow labeled instructions.

  • NEVER dry sweep or vacuum a rodent infested area. ALWAYS use wet cleaning methods.
  • ALWAYS wear rubber gloves, long sleeves, protective eyewear and a dust mask when cleaning. This will help protect you from contamination, and from coming in contact with potentially harmful chemicals.
  • A 10 parts water to 1 part chlorine bleach solution or a household disinfectant can be used to clean up contaminated areas.
  • Put on gloves, then spray dead rodent with disinfectant.
  • With gloves still on, pick up the rodent, place it in a bag and seal it. Place the bag in another bag and seal it. Put the bag in a covered outdoor trash can that is regularly emptied.
  • When you’re done cleaning, wash your hands thoroughly with warm water and soap, and dry with paper towels. Launder your clothes normally.

More about cleaning up after a rodent infestation»

Helpful Resources

Rodent Prevention & Control Brochure (574.09 KB)
Centers for Disease Control & Prevention - Rodents

Contact Us

Multnomah County Vector Control
5235 N Columbia Blvd
Portland, OR 97203