Roof rats in the San Fernando Valley: a homeowner's guide
If you hear running in the ceiling at night, you're not alone. Roof rats are one of the most common pest problems in the Valley.
Updated October 2026.
Why the Valley suits roof rats
Roof rats are excellent climbers that prefer to nest above ground. Valley neighborhoods give them exactly what they want: backyard fruit trees (citrus, avocado, figs), ivy and dense hedges for cover, block walls and utility lines as travel routes, and attics with gaps around vents and rooflines. Pet food and birdseed left outside add easy calories.
Signs of roof rats
- Running or scratching above the ceiling, usually starting after dark
- Droppings in the attic, garage or along walls; roof rat droppings are about ½ inch with pointed ends
- Citrus fruit hollowed out while still on the tree
- Dark grease rub marks at entry points
- Chewed wires, insulation tunnels, or nests of shredded material in storage boxes
A step-by-step plan
- Cut off the highways. Trim tree branches several feet back from the roof, thin ivy on fences and walls, and keep palm skirts trimmed.
- Remove food. Pick up fallen fruit daily, harvest ripe fruit promptly, store pet food and birdseed in sealed containers, and use lidded trash and compost bins.
- Trap active rats. In the attic and garage, snap traps placed along runways (walls, beams) work well. Wear gloves and check traps daily.
- Seal entry points. After activity stops, close gaps with ¼-inch hardware cloth, metal flashing or rodent-proof sealant. Check roof and gable vents, plumbing and cable penetrations, the garage door seal and the roof-to-wall junction.
- Clean up safely. Rodent droppings can carry disease. Ventilate, wet droppings with a disinfectant before wiping (don't sweep or vacuum dry droppings), and wear gloves.
Why we don't recommend DIY poison
Many anticoagulant rodenticides are restricted in California because they poison hawks, owls, bobcats and pets that eat affected rodents. Poisoned rats also tend to die inside walls, causing odors. Trapping plus exclusion is safer and more permanent.
When to call a professional
If you can't find the entry points, have activity in multiple areas, or see significant insulation damage, a professional inspection and exclusion job is usually worth it. Call the number on this page to connect with a local provider.