In Southern California, there really isn’t an “off season” for rodents. Our mild winters mean that once a colony finds its way into a home, it can keep breeding right through spring and summer instead of dying back in the cold. By the time you hear a scratch in the wall or spot a few droppings, the rodents may have been inside for four to six weeks already.
We started Fowler Pest Control in 2001 right here in the Inland Empire, so we’ve seen how our local climate, building styles, and ongoing development shape rodent problems in Murrieta and the surrounding area. This guide is built around what actually happens in Southern California homes, not a generic national checklist that assumes snow, deep freezes, or products you can no longer buy here.
If you’re wondering whether you really have a rodent issue or just the occasional outdoor visitor, we’ll walk through what to look for, what you can safely do on your own, and when it is time to bring in help.
Why Southern California Homes Face Year-Round Rodent Pressure
Rodents are always looking for warmth, food, and shelter. In colder regions, long freezes knock populations down each winter, so infestations tend to spike in fall and taper off by spring. In Southern California, there is no similar reset. Once roof rats or Norway rats settle into a yard or attic, they can stay active and keep expanding their colony all year.
Across the Inland Empire, constant development adds even more pressure. As open land and fields are cleared for new neighborhoods, warehouses, and roads, rodents lose their natural habitat and move straight into the next available shelter. Since 2023, we’ve seen more situations where new construction pushes rats and mice into nearby established homes that never had a problem before.
In Murrieta and Riverside County, two rat species cause most of the trouble inside homes: roof rats and Norway rats. Understanding how each one behaves makes it much easier to know where to inspect and what you are dealing with.
- Roof rats (Rattus rattus): These rats are agile climbers that prefer to live above ground. They use trees, fences, and utility lines as highways, then slip into homes through attic vents, gaps near eaves, and loose roof tiles.
- Norway rats (Rattus norvegicus): These rats are bulkier and spend more time at or below ground level. They burrow under slabs, nest in crawl spaces, and enter through gaps near foundations, pipes, and ground-level vents.
Because they are active year-round, a small opening around your roofline or foundation doesn’t just attract pests in the fall. It can serve as a revolving door every week of the year unless it is sealed.
Six Signs You May Have a Rodent Problem
The first goal is to figure out whether you are dealing with an active infestation or an old issue that has already been resolved. These are the signs we coach homeowners to look for when they call us with a “maybe” problem.
- 1. Fresh versus old droppings. Fresh rodent droppings are usually dark, slightly shiny, and soft enough to crush. Older ones turn grayish, dry out, and crumble like chalk. A simple way to test for active activity is to clean up all visible droppings using gloves and a disinfectant, then check the same spots again after 24 to 48 hours. New droppings in the same area mean you have ongoing traffic.
- 2. Scratching or scurrying sounds at night. Both roof rats and Norway rats are primarily nocturnal. If you consistently hear light scratching, scampering, or squeaking in the attic, walls, or ceiling after dark, that strongly suggests rodents are moving around above you while the house is quiet.
- 3. Gnaw marks on wood, plastic, or wiring. Rodents’ teeth grow continuously, so they have to gnaw to keep them worn down. You might see bite marks on baseboards, door corners, food packaging, storage bins, or even electrical wiring. Fresh gnawing usually looks lighter and less weathered than the surrounding material and may be surrounded by wood shavings or debris.
- 4. Grease rubs and “runways.” Rodents tend to follow the same paths along walls and behind objects. As they move, the oils in their fur leave faint dark or greasy streaks on baseboards, pipes, or beams. Over time, these trails become pretty clear “runways” that reveal where they travel most often.
- 5. A musky, stale odor. A strong, persistent musty smell in a confined area like a pantry, closet, or attic corner can indicate a nest or heavy rodent activity. That odor builds up over time, so it often means the infestation has been there longer than you realized.
- 6. Nesting materials and shredded debris. Rodents build nests out of whatever soft materials they can find: insulation, fabric, paper towels, cardboard, and even car seat stuffing. If you find piles of shredded material tucked into corners, inside boxes, or near appliances, that’s a sign rodents are not just passing through, they are settling in.
You don’t have to see a live rat or mouse to have a real problem. In many homes we treat, the first solid evidence is a combination of droppings and sounds at night, with visual sightings only happening after the population grows.
Where Rodents Get In — And Why It Matters Which Species You Have
Rodents only need small gaps to enter. Roof rats can squeeze through openings about half an inch wide, and Norway rats only need slightly more. Where those gaps are located often tells us which type is inside and where to focus control efforts.
Common Roof Rat Entry Points
If most of the activity seems to be above you, roof rats are a good bet. They like to nest in attics, soffits, and wall voids near the roofline. Typical access points include:
- Gaps around attic vents or louvers
- Spaces at the edges of roof tiles or loose shingles
- Openings where utility lines meet the house
- Overhanging tree branches that touch or hang close to the roof
In these cases, we encourage homeowners to look up: long, drooping tree limbs, ivy running up walls, and nearby power lines all make it easy for roof rats to reach your roof and find a way in.
Common Norway Rat Entry Points
Norway rats typically stay closer to the ground. They dig burrows along foundations, under concrete slabs, and around steps or patios. They will often enter through:
- Cracks in foundations or stem walls
- Gaps around plumbing, A/C lines, or other utility penetrations
- Loose or missing crawl space vent screens
- Burrows under sheds, decks, or wood piles that connect back toward the house
If you are noticing droppings in garages, under sinks, in crawl spaces, or near exterior garbage areas, a ground-level Norway rat issue is more likely.
Correct identification matters because it directs your plan. Traps set on attic beams will not do much for a ground-burrowing population, and sealing only the bottom of the house won’t stop a roof rat colony using the trees overhead. When we inspect, we combine droppings size and shape, gnaw mark locations, and activity patterns to confirm which species is present and tailor the rodent exclusion and control work accordingly.
What You Can Do Right Now: Prevention Steps That Actually Work
Even before anyone sets a trap, there is a lot you can do to make your home less attractive to rodents. Good Integrated Pest Management, or IPM, starts with removing what rodents need to survive and blocking their access.
Harborage Reduction Around the Home
“Harborage” is the term for places rodents can hide and nest. Reducing it makes your yard and home far less inviting.
- Move woodpiles and debris. Keep firewood, lumber, and stored items at least 10 to 15 feet away from the house and raised off the ground when possible.
- Trim trees and shrubs. Cut back branches that touch or hang over the roof, and thin dense shrubs so they don’t provide hidden tunnels along walls and fences.
- Secure garbage and compost. Use tight-fitting lids on trash and green waste bins, and avoid leaving bags of garbage or pet waste on the ground overnight.
- Store food properly. Keep pet food, birdseed, and bulk pantry items in sealed hard containers instead of bags that can be chewed through.
Entry Point Sealing That Holds Up
Rodent exclusion is all about physically blocking the paths rodents use to get inside. A few simple materials can go a long way.
- Fill small gaps with steel wool and sealant. For cracks and holes around pipes, cables, and other penetrations, pack in steel wool and then cover it with caulk or sealant. Rodents don’t like chewing through metal fibers.
- Add metal mesh to vents. Install quarter-inch or smaller hardware cloth over attic and crawl space vents so air can flow but rodents can’t squeeze through.
- Use door sweeps and weatherstripping. Make sure exterior doors, including garage side doors, close snugly with no visible light at the bottom or sides.
- Repair damaged screens and gaps. Fix torn window screens and seal any gaps where different building materials meet, such as stucco to wood.
Monthly Monitoring for Early Warning Signs
Catching an issue in the first few weeks is the difference between a minor clean-up and a full-scale infestation. A simple monthly walkthrough can help.
- Check “hot spots.” Look in pantries, under sinks, behind appliances, in garages, and in attic access areas for droppings, gnaw marks, or disturbed insulation.
- Watch for changes in pet behavior. Dogs and cats often notice wall or attic activity before we do. If they suddenly focus on one corner or stare at the ceiling at night, it may be worth a closer look.
- Track any new signs. If you clean an area and new droppings, rub marks, or shredded material appear within a day or two, that is a strong sign of an active infestation.
These steps won’t replace professional control once rodents are established, but they can slow things down, prevent new problems, and support any treatment plan.
Why California’s Rodenticide Laws Change the DIY Equation
For years, many homeowners relied on store-bought bait blocks and pellets as their default rodent control method. That landscape has changed significantly in California.
California AB 2552, known as the Poison-Free Wildlife Act, takes effect January 1, 2025. This law prohibits residential use of all anticoagulant rodenticides, both first- and second-generation. These are the active ingredients that used to dominate the bait products on hardware store shelves.
Under AB 2552, products with these ingredients must be sold by licensed dealers and can only be applied by licensed professionals. The goal is to protect wildlife like hawks, owls, mountain lions, and coyotes, as well as pets, from rodent-borne poison that moves up the food chain when a poisoned rodent is eaten.
In practical terms, this means a few important things for homeowners:
- Many familiar baits will no longer be available for DIY use. You may still see traps and non-anticoagulant products in stores, but the most common traditional baits are now restricted.
- Effective baiting now sits mostly in professional hands. Licensed companies can still use these tools when appropriate, within strict guidelines and as part of a broader IPM plan.
- Your main DIY tools are now trapping and exclusion. Snap traps, multi-catch traps, careful sanitation, and sealing entry points are the key actions available if you prefer to start on your own.
We support the intent of AB 2552, because we live and work in the same communities and value healthy wildlife corridors. It does, however, make professional, science-based rodent control the responsible default in many situations, especially when infestations are larger or located in complex structures.
When to Call a Professional — And What to Expect
Not every single dropping requires immediate professional help. But there are clear signs that the problem has moved beyond a simple DIY fix and needs a structured, Integrated Pest Management approach.
Signs It Is Time to Bring in Help
- Droppings keep returning after cleanup. If you’ve cleaned thoroughly and still find fresh droppings in the same spots a day or two later, rodents are actively using those areas.
- Sounds in multiple parts of the home. Activity in both the attic and walls, or in separate levels of the house, suggests a larger or more established colony.
- Gnawing on electrical wiring or critical components. This isn’t just a nuisance, it can become a fire hazard and should be addressed quickly.
- Strong, lingering musky odor. A powerful smell in confined areas often points to nests or heavy rodent traffic that has been present for weeks.
- Daytime sightings. Rodents out in the open during daylight hours sometimes indicate overcrowding or a severe infestation.
What a Professional IPM Visit Typically Includes
When we respond to a rodent call, we follow a structured process designed to fix the current problem and reduce the chances it comes back.
- Detailed inspection. We look inside and outside the home to identify the species involved, find entry points, and map out harborage areas and travel routes.
- Targeted trapping and removal. Based on what we find, we place traps where rodents are already traveling, and we choose methods that fit your home and household.
- Entry point sealing and exclusion recommendations. We identify and address the gaps, cracks, and construction features that allowed rodents in, using materials they can’t easily chew through.
- Sanitation and monitoring guidance. We explain how to clean up safely, reduce attractants, and watch for any signs of renewed activity.
At Fowler Pest Control, we’ve been helping Southern California homeowners deal with rodents since 2001. We use products and methods that are safe for children, pets, and landscaping, and we build our work around Integrated Pest Management principles instead of relying only on chemicals. We also offer free estimates and strive for same-day scheduling and emergency service when you need a fast response.
Staying Ahead of Rodents in a Year-Round Climate
In our climate, rodents don’t wait for a particular season to move in, and the time between the first entry and a fully established nest is often just a few weeks. The sooner you notice and act on early signs like fresh droppings, nighttime noises, or gnaw marks, the simpler and more affordable the solution tends to be.
If you’re not sure whether you are looking at a minor issue or the start of something bigger, a quick professional inspection can give you clear answers and a plan. You can always reach our team at Fowler Pest Control at (951) 447-4670 for an estimate and practical, locally grounded guidance on what to do next.