Rodent Prevention: Find the Route, Then Close It

1Make a ground-level route map

Walk only areas you can reach safely. Check door edges, foundation vents, utility penetrations, accessible eaves, and vegetation touching the building. Note gnaw marks, rub marks, noises, and droppings without disturbing them. Mark each location on a simple sketch and add a date. Do not enter an unsafe attic, roof, or crawl space to finish the map.

• Photograph an opening with a nearby object for scale and note whether it looks used.
• Record where and when you heard activity; a sound alone does not identify the animal.
• Ask a qualified provider to inspect concealed or hazardous spaces.

2Remove food, water, and cover you can control

Use closed containers for pantry goods, pet food, and refuse. Clean food spills, collect fallen fruit, and address leaks. Trim plants that give rodents cover or access to a roof, using a qualified contractor when the work is out of safe reach. These steps reduce attraction, but they do not replace a search for entry points.

• Keep trash lids closed and do not leave pet food out overnight.
• Move stored materials away from the building where possible so walls and vents can be inspected.
• Put maintenance requests for damaged doors, screens, and leaks in writing.

3Coordinate trapping and exclusion

Show the route map to the provider or maintenance lead before sealing an active opening. Ask how they will check for animals inside, manage activity, and confirm when a route is ready to close. UC IPM recommends durable metal or concrete at entry gaps; foam and other soft materials can be gnawed through. Trap choice and placement depend on the animal, the location, and access by children or pets. In a 2021 study of two New Jersey apartment towers, Sked and colleagues found that mouse activity fell after building-wide management but rose above baseline in one building by the 12-month check. That house-mouse result is a reason to keep inspecting shared routes, not a predicted outcome for California homes or rats.

4Treat droppings as a separate cleanup task

Do not dry sweep or vacuum droppings, urine, or nests. CDC directs people to wet contaminated material with an appropriate disinfectant and follow the product instructions before wiping it up. Read its full cleanup guidance before starting a small accessible job. For heavy contamination, hidden spaces, or a task that requires climbing or disturbing insulation, get qualified help.

• Keep people and pets away from the area until it has been assessed and cleaned.
• Do not improvise chemical mixtures or use a household vacuum on the waste.
• Retain the route map and note any new signs after repairs.
• If fresh signs appear, note whether they are near the repaired opening or elsewhere so the next inspection can test the route map.