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Eliminating Rodent Harborage

Rats dislike being out in the open, and will seek cover whenever possible. You can make your property less hospitable to rats by cutting back or removing vegetation and removing other items that provide cover for rats, especially close to your home and other structures.


Fruiting plants and trees provide a food source for rats, including citrus trees and vegetable gardens. You should diligently harvest ripe fruits and vegetables, and consider avoiding ornamental plants that produce fruit. Sheet metal collars can be used to keep rats from climbing tree trunks, but are only effective if the tree is too far from other objects to allow rats to access it by jumping.

Firewood and stacked lumber should be stored a minimum of 18 inches above ground and 12 inches away from fences and walls. Other debris should be discarded or stored indoors to avoid creating harborage for rats.

Stored vehicles can sometimes be infested by rats; this can be avoided by regularly uncovering, starting, and moving them.

Trees and bushes should be trimmed back at least 4 feet from roof and walls.

Some plants commonly used in landscaping in our county are especially attractive to roof rats and should be avoided if possible: Algerian and English ivy, blackberry, jasmine, honeysuckle, bamboo, pampas grass, bougainvillea, oleander, and Italian cypress. If these plants are used, they should be kept thinned to discourage rats from nesting. Plants used for groundcover should be kept short.

Proper landscaping to discourage roof rat activity:


May contain: rug


 Limiting Access to Food Sources

Rats will eat almost anything, so it is important to be diligent in denying them access to food sources. This will also help drive rats to bait in traps and bait stations, making other control measures more effective.

If you will be keeping or feeding pets or livestock outdoors, only supply as much food as can be eaten at that time, and clean up any spilled or leftover feed. If you choose to feed wild birds, feeders should be of a rat-proof design or should be brought inside at night. Any spilled seed on the ground should be cleaned up. You may want to stop feeding birds when there is an active rodent infestation on or near your property. Animal feed stored outdoors should be kept in metal containers with tight-fitting lids.

Garbage, recycling, and compost should be kept in rat-proof bins. Pet feces should be cleaned up promptly and discarded in closed containers.

Leaks and standing water should be eliminated whenever possible to reduce rats’ access to water.

For assistance with any of these prevention techniques, or to schedule an inspection, please contact the District at (650) 344-8592.

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