Rats can spread disease, contaminate food, and cause costly structural damage. They are found in all areas of the County. Learning to recognize signs of rat activity, and how to prevent and control rat problems can protect you and your home against rats. 

The Vector Control Program provides educational rodent inspections FREE to County residents. It includes a Rat Control Starter Kit and instructions on how to properly implement rat control techniques. The Vector Control Program is not a pest control company and does not trap, bait, or remove rodents as part of the inspection, and does not provide poison bait. 

To request a rat inspection contact the Vector Control Program.

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Rat Facts

Unwanted rats are pests that can pollute food, spread disease, and cause damage by gnawing. Rats are most active at night. Rats eat many types of food, including human food, pet food, bird seed, and trash. 

Roof Rats: The most common type of rat in San Diego County, roof rats like to climb, rather than burrow. They live above ground and are gray or brown in color.

Norway Rats: Not commonly found in San Diego County, Norway rats prefer to burrow outside, are bigger than roof rats, and show a wide range of colors.

Wood Rats: Build nests out of sticks and debris, and are not found in homes, but some nest in outbuildings and even cars. They are gray or brown in color.

Rat Diseases

  • Plague: People and animals can be infected with plague from fleas that feed on infected rats, or from being bitten by an infected rat.
  • Food poisoning: Eating food that has been polluted with rat urine or droppings can cause food poisoning.
  • Rat-bite fever: A bite from an infected rat can cause rat-bite fever.
  • Parasites: Some rats can carry tapeworms.

Signs Of Rat Activity

  • Bark stripped from plants and trees
  • Piles of cut snail shells hidden under plants or piles of wood
  • Sounds in the attic, floor, and walls
  • Rat droppings in garages, storage buildings or other sheltered areas
  • Rub marks caused by greasy rat fur
  • Damaged food containers
  • Damaged food
  • Signs of gnawing

Prevention and Control

Rats cannot live without food, water, or shelter. Here's how to get rid of rat problems.

1. Rodent proof your home and storage buildings.

  • Check the outside of your house for holes or gaps the size of a quarter or larger
  • Repair all openings using rodent proof materials: 1/4-inch, 18-22 gauge wire hardware cloth
  • Install metal weather stripping under doors to remove gaps

2. Remove food sources from your property.

  • Always keep garbage cans covered
  • Pick fruit, nuts, and vegetables as they ripen, and throw away or compost fallen fruit on the ground
  • Feed pets during daylight hours only, and remove uneaten food right away
  • Avoid storing food in garages and storage sheds at night unless in rat-proof covered metal containers
  • Avoid feeding birds, or clean up any fallen bird seed around feeders

3. Get rid of rat habitat.

  • Remove all trash and debris
  • Stack woodpiles, lumber, and household items at least 18 inches above the ground and 12 inches away from fences and walls
  • Trim trees, bushes, and vines to at least 4 feet away from the roof
  • Remove heavy vegetation such as ivy, bougainvillea, and pyracantha from buildings and fences
  • Thin vegetation to allow daylight in and remove rat hiding places

4. Inside your home use traps, not poison bait.

  • Use snap traps indoors since poisoned rats may die inside walls or attics, creating odors and attracting flies
  • Place traps at entry points, or where you have seen rat droppings
  • Use CAUTION when placing traps around children or pets
  • Bait the traps with peanut butter or the food the rats have been eating
  • Tie down traps to prevent injured rats from dragging the traps away and dying inside your walls
  • Check traps at least twice a week

5. Outside your home use traps and poison bait (if necessary).

  • Place traps where rodent activity has been observed
  • Keep bait away from children and pets
  • Rodent proof your home BEFORE using poison bait
  • Always read the label and follow directions when using poisons
  • Multi-dose, anti-coagulant poisons are the most effective, as rats may need to feed on the bait for several days
  • Place poison bait in an enclosed bait station, where you see rats and their droppings
  • Make sure bait is in a protected area, such as under woodpiles or thick vegetation where rats may be hiding
  • Check bait stations twice a week and add bait when necessary
  • Place dead rats in sealed plastic bags and put them in the trash

Rat Inspections

The Vector Control Program provides educational rodent inspections FREE to County residents (inspections are performed on the exterior of buildings and only in San Diego County). This inspection includes a free Rat Control Starter Kit. The kit enables you to control rats yourself and provides examples of materials needed. It includes:

  • Tamper-resistant Trapping Station and key
  • Rat Control Brochure
  • 1 Rat Snap Trap
  • 1/4" Sample Hardware Cloth (used for exclusion)

The Vector Control program is NOT a pest control company and does NOT trap, bait, or remove rodents as part of this inspection, and does not provide poison bait.

To request a rat inspection contact the Vector Control Program.


  (858) 694-2888



Roof Rat photo by H. Zell