Getting rid of a rat infestation requires a three-phase approach: cut off their food and shelter, trap or kill the existing population, and seal every entry point so new rats can’t move in. Skipping any one of these steps is why most DIY efforts fail. Rats breed fast, are surprisingly cautious around new objects, and can squeeze through gaps smaller than you’d expect. Here’s how to systematically eliminate them.
Identify Which Rat You’re Dealing With
The two most common species in homes are Norway rats and roof rats, and knowing which one you have changes where you focus your efforts. Norway rats are stocky, seven to ten inches long, with blunt snouts and small ears. They prefer ground level and below: burrows in yards, basements, crawl spaces, and ground-floor walls. Roof rats are sleeker and slightly smaller (six to eight inches), with pointed noses, large ears, and tails longer than their bodies. They climb well and nest in attics, rafters, and upper stories.
Don’t rely on color alone. Both species come in shades of brown and gray despite their common nicknames (“brown rat” and “black rat”). Instead, look at body shape and where you’re finding droppings. Droppings in the attic or along upper shelving point to roof rats. Droppings in the basement, along foundation walls, or near ground-level garbage suggest Norway rats. This tells you whether to focus your traps and exclusion work high or low.
Start With Sanitation
Rats stay where food is easy to find. Before you set a single trap, remove every food source you can. Store all pantry items in glass or heavy plastic containers. Keep pet food in sealed bins and don’t leave bowls out overnight. Move outdoor garbage cans away from the house and make sure lids close tightly. Pick up fallen fruit from trees, clean up birdseed under feeders, and if possible, remove feeders entirely until the infestation is resolved.
Declutter storage areas, especially garages, basements, and attics. Rats nest in cardboard boxes, piles of fabric, and undisturbed junk. Eliminating hiding spots makes your property less hospitable and forces rats to cross open ground where traps are waiting.
Trap Placement and Technique
Snap traps remain the most effective and safest option for most homeowners. They kill quickly, don’t pose secondary poisoning risks, and let you confirm each kill. The key is placement, not just quantity.
Set traps along walls, fence lines, or any linear surface like the edge of a planter box. Rats are creatures of habit and travel the same routes repeatedly, usually hugging walls and edges. Position the trigger facing the wall, or place two traps side by side with triggers facing away from each other. You can also line up three traps in a row with alternating trigger directions. These configurations catch rats coming from either direction.
Use a pea-sized amount of bait, not a heaping glob. Good choices include peanut butter, dried fruit, or whatever food you’ve noticed the rats eating. For rats specifically, prebaiting is important: place baited but unset traps for a couple of days until you see the bait being taken repeatedly. Rats are cautious around new objects (a behavior called neophobia), and prebaiting lets them get comfortable before you arm the traps. Once the bait is being taken consistently, set the triggers.
For a moderate infestation, plan on at least a dozen traps. A common mistake is setting two or three and wondering why nothing happens. Spread them across every area where you’ve found droppings, gnaw marks, or grease smears along walls.
Seal Every Entry Point
This is the step most people skip, and it’s the most important for long-term success. Rats can fit through any gap their skull fits through, which for a Norway rat means an opening roughly the size of a quarter. Inspect your entire exterior: foundation vents, gaps around pipes and conduit, spaces under doors, roof eaves, and where utility lines enter the building.
Seal openings with materials rats can’t chew through. Stainless steel wool, copper mesh, or brass wool stuffed tightly into gaps works well. For larger holes, use steel mesh or hardware cloth secured with screws. Expanding spray foam alone is not enough because rats gnaw through it easily, but foam combined with steel wool inside the gap creates a more durable seal. Replace damaged vent screens with heavy-gauge metal mesh.
For roof rats, pay special attention to the roofline. Check where the roof meets the walls, gaps around attic vents, and any overhanging tree branches that provide access. Trim branches back at least four feet from the roof.
When Rodenticides Make Sense
Poison bait is sometimes necessary for severe infestations, but it comes with real trade-offs. If you go this route, understand what’s available and what isn’t. The EPA restricts what consumers can buy: second-generation anticoagulant baits (the most potent type) are not sold to retail customers at all. You can purchase first-generation anticoagulants and non-anticoagulant baits, but only in packages of one pound or less, only in block or solid form (not pellets), and they must come with a bait station.
All outdoor, above-ground bait placements require a tamper-resistant bait station to protect children, pets, and wildlife. This is not optional.
The biggest concern with rodenticides is secondary poisoning. When a rat eats poison and then dies in the open, any animal that scavenges the carcass can be poisoned too. This is a significant risk for dogs, cats, hawks, and owls. If you have pets that roam your property, or if your area has raptors and other wildlife, trapping is the safer choice. If a pet does ingest bait or a poisoned rodent, contact the Poison Control Center at 800-222-1222 immediately.
Safely Clean Up Droppings and Nests
Rat droppings can carry serious diseases, including hantavirus. Never sweep, vacuum, or dust contaminated areas. Sweeping launches dried particles into the air where you can inhale them.
The safe cleanup process starts with ventilation. Open windows and doors and leave the space for at least one hour. When you return, wear rubber or latex gloves and a half-face respirator with a HEPA filter (a basic dust mask is not sufficient). Mix one cup of bleach into ten cups of water and thoroughly spray or soak all droppings, nesting material, and dead rodents. Let everything soak for at least five minutes before wiping up with rags or paper towels.
Wipe down countertops, cabinets, and drawers in affected areas. Mop floors and baseboards with the bleach solution. Steam clean any carpets, rugs, or upholstered furniture that may be contaminated. Wash clothing and bedding in hot water with detergent and dry on high heat. Bag all contaminated waste in sealed plastic bags and place them in your outdoor garbage. Disinfect or discard your gloves, then wash your hands thoroughly with soap and hot water.
Signs You Need Professional Help
If you’ve been trapping for two to three weeks, sealed obvious entry points, and removed food sources but still see fresh droppings or hear activity in the walls, the infestation is likely larger or more entrenched than DIY methods can handle. Other signs that it’s time to call a professional include rats in multiple areas of the building, structural damage to walls or wiring, or evidence of burrowing under your foundation.
Licensed pest control operators have access to commercial-grade tools, second-generation rodenticides (restricted from retail sale), and the experience to locate entry points you might miss. For severe infestations, professional treatment typically involves an initial knockdown phase using a combination of trapping and bait, followed by a thorough exclusion job that seals the structure. Expect the active removal phase to take anywhere from a few weeks to a couple of months depending on the severity, with follow-up monitoring after that.
Preventing Reinfestation
Once the infestation is cleared, ongoing prevention is straightforward but non-negotiable. Inspect your home’s exterior at least twice a year, once in early fall when rats are most likely to seek indoor shelter, and once in spring. Recheck all your sealed entry points for signs of new gnawing. Keep vegetation trimmed away from the structure, maintain clean garbage storage, and store firewood at least 20 feet from the house and elevated off the ground.
A few snap traps left in the attic, basement, or garage serve as an early warning system. Check them monthly. Catching one rat early is a manageable problem. Discovering fifty is not.