See our resources to detect and prevent rats.


Norway rat is the most commonly found rat, also known as the brown rat or sewer rat.

  • Norway rats are larger rodents that weigh about 11 ounces
    • Total size length is about 13 to 18 1/2-inch
    • Body is 7 to 10 inches and tail is as long as body, about the 6 to 8 1/2-inch.
  • Indoors
    • Norway rats tend to remain in basements, spaces in between walls or the ground floor.
  • Norway rat builds burrows along:
    • Building foundations
    • Beneath rubbish
    • Around gardens
    • In unused sewers and storm drains.

Rats can be a problem

  • Rats eat and contaminate food
  • Rats damage buildings and other property by their gnawing and burrowing behavior

Transmissible diseases

Rats can spread diseases to people and pets:

  • Murine typhus
  • Leptospirosis
  • Salmonellosis
  • Plague
  • Rat bite fever
  • Other diseases

Signs of infestation

  • Droppings that are about 3/4-inch long and 1/8 inch in diameter throughout building
  • Urine staining (use black light for better visibility)
  • Gnawed doorways and/or food packaging (look for spilled foods)
  • Rat tracks in areas with heavy debris, dust, or mud
  • Rub marks on walls in heavily traveled areas
  • Burrows are usually found in earth banks, along walls, under rubbish and outdoor buildings
  • Musty, pungent odor
  • Sounds at night such as a scratching, gnawing, and fighting



  • Seal all holes or gaps with areas larger than 1/2 inch on outside buildings
  • Maintain outdoor areas clean and free of clutter
  • Keep lids to disposal bins closed
  • Keep bushes and shrubbery trimmed


  • Know how to spot the signs of rat activity and monitor any troublesome areas.
  • Maintain areas free of food debris.
  • Remove cardboard and clutter from rooms.
  • Seal all electrical conduits, heating ducts, pipes, and pipe chases.
  • Install door sweeps and other devices to seal any holes or cracks leading to outside.
  • Provide routine maintenance and spot checks to all areas of building to prevent rats getting in.
  • Work with pest control company to determine a regular schedule that fits your building needs.

Call a professional extermination company if you suspect there are rats within your facility.

Watch for an increase in rat activity as seasons change.

More about rats

  • Eat any type of food, but prefer high-quality foods such as meat and fresh grain
  • Are primarily active at night
  • Have poor eyesight, but keen sense of taste, hearing and smell
  • Can enter structures by gnawing, climbing and jumping
  • Can swim through sewers and enter buildings through toilets or broken drainpipes
  • Can enter opening larger than 1/2 inch across

Interesting rat facts

  • Rats constantly explore and learn about their environment
  • Rats memorize the locations of pathways, obstacles, food, water, shelter and other elements in their area
  • Rats can quickly detect and tend to avoid new objects placed in a familiar environment

Lodging complaint

You can report an unsanitary hotel, motel or other type of lodging in the city.

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Contact us

Environmental Health

Minneapolis Health Department




Public Service Center
505 Fourth Ave S, Room 520
Minneapolis, MN 55415