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1. What are common signs of roof rat activity?

- Visual sightings on power lines, trees, bushes, patios, etc.
- Hollowed out citrus and other fruit
- Rat droppings
- Noises in the attic and walls
- Gnawing sounds and gnaw marks around roof eaves
- Damage to plastics and coverings on electrical wires
- Unsettled pets

2. What should I do if I see evidence on my property?

Call the Maricopa County Environmental Complaint Line at 602-506-6616 or submit a Complaint Form. Vector Control officers identify and test rat specimens throughout Maricopa County. Environmental Services Complaint Form

3. How should I handle dead rats, rat droppings, and nesting areas?

- Use rubber gloves
- Ventilate the affected area the night before cleanup by opening doors and windows
- Spray dead rats, droppings, nests and surrounding areas with a 10% bleach solution (one part bleach and 9 parts water). Allow at least 15 minutes of contact time before removal.
- Clean the affected area with paper towels or a mop. Do not sweep or vacuum. Double bag both the disinfectant-soaked rat and cleanup materials securely in plastic bags and seal. Dispose in city trash containers.
- Before removing gloves, wash in disinfectant, then soap and water. Dispose of gloves with other household waste. Thoroughly wash hands with soap and water.

4. Where have roof rats been found?

Common places where roof rats have been found are in swimming pools, laundry rooms, attics, garages and patios. They’ve been seen on power lines in the alleys. Roof rats spend 90% of their life 4 feet or more off the ground.

5. When do they travel?

During twilight and nighttime hours in a territory 200 to 300 feet from their daytime nesting locations. They thrive in cool weather and are most active from November through May.

6. How do they travel?

Roof rats are strongly arboreal and travel along power lines to trees, oleanders, vines and roofs. They can climb up brick walls and other rough surfaces. They can jump 2 feet straight up and 4 feet horizontally (double the horizontal distance if they are jumping from a height). Bear in mind that ground covers and compost bins also provide safe travel routes and nests.

7. How do they enter homes?

They enter homes and garden sheds through any opening larger than a nickel. They follow pipes down from the attic, gnaw through drywall, and enter the kitchen or base sink cabinets. They chew through wood, plastic, aluminum siding, sheet rock and soft metals.

8. Why attics?

These rodents are fond of attics because they provide a safe refuge, a nesting place for their young and routes into the home below.

9. What do they eat and drink?

They love to eat citrus fruit (because it serves as both a food and water source) and other fruit (pomegranates, figs, etc.), nuts, seeds and stored grains, and vegetables in your garden. They also eat insects, lizards, tree bark, soap, paper, hides, and beeswax.

Bird seed (both in feeders and stored in bags) and dog and cat food left outside after dark are favorites. Roof rats eat Queen Palm tree fruits in the summer when citrus isn’t available.

Water sources include leaky faucets and sprinkler heads, bird baths, fountains and ornamental ponds, irrigation, air conditioner condensation drip lines, saucers under potted plants, and pet water dishes. They will chew through metal and plastic pipes to reach water.

10. How do I seal my home?

The most extensive damage occurs when roof rats enter the home, so the first goal is to keep them out. Use stucco diamond mesh available at building material suppliers to screen and seal all holes and vents leading into your home or garden shed. It cuts and molds very easily. For the rat, this mesh is like biting into small razor blades.

Look for holes in exterior walls and near hot water heaters, washers and dryers, dishwashers, and under sinks. Don’t forget to screen off the sewer stacks on the roof. All cracks should be caulked.

Stuff the cover of the air conditioning line that runs from the outside unit into the attic with steel wool or copper mesh to prevent rats from climbing up the insulated pipe inside the cover. Look for scratch marks on the insulation, and then set a snap trap there to catch them the next time they use that entrance.

11. Do roof rats carry disease?

Roof rats throughout Maricopa County continue to be tested for tularemia (rabbit fever), hantavirus and plague. All tests to date have been negative.