Getting rid of rodents requires a combination of sealing entry points, removing food sources, trapping or baiting, and cleaning up safely. No single step works on its own. A mouse can squeeze through a hole the size of a dime, and a rat can fit through one the size of a quarter, so even small gaps in your home’s exterior are an open invitation.
Identify What You’re Dealing With
Before you start setting traps, figure out whether you have mice or rats, because the two require different approaches. Droppings are the easiest clue. Mouse droppings are about 1/4 inch long and look like dark grains of rice with pointed ends. Roof rat droppings are roughly 1/2 inch long, curved, and scattered around. Norway rat droppings are the largest at about 3/4 inch, rectangular with blunt ends, and typically found in small clusters rather than spread out.
Fresh droppings from any species are dark, shiny, and soft. Older ones turn gray, dry, and crumbly. The freshness tells you whether the infestation is active or leftover from a past problem. Other signs include greasy rub marks along walls (rats leave these as they travel the same paths repeatedly), gnaw marks on food packaging or wood, and scratching sounds in walls or ceilings, especially at night.
Seal Every Entry Point
Exclusion is the most important step and the one most people skip. If you trap or poison rodents without sealing their entry points, new ones will simply move in. Start with a thorough inspection of your home’s exterior. Look for any opening larger than 1/4 inch, paying close attention to where pipes, wires, and cables enter the building. Check the gaps under doors, around dryer vents, along the foundation, and where the roof meets the walls.
The best permanent materials for sealing gaps depend on the size of the opening:
- Hardware cloth (wire mesh): Use 1/4-inch by 1/4-inch mesh in 24 gauge to exclude mice, or 1/2-inch by 1/2-inch mesh in 19 gauge if you’re only dealing with rats. Secure it over vents, windows, and larger openings.
- Galvanized sheet metal: 24 gauge or heavier works for covering gaps along walls, doors, and foundations. Rodents can’t chew through it.
- Concrete: Reinforced concrete needs to be at least 2 inches thick to stop rodents. Unreinforced concrete should be 3-3/4 inches.
- Copper or stainless steel wool: For gaps under 3/4 inch that are hard to cover with solid materials, stuff them tightly with copper or stainless steel wool. Regular steel wool works temporarily but rusts over time.
Don’t rely on expanding foam alone. Rodents chew through it easily. If you use foam for insulation, cover it with hardware cloth or sheet metal on the exterior side.
Eliminate Food and Water Sources
Rodents stay where they can eat. Store all pantry items in glass, metal, or thick plastic containers. Keep pet food in sealed bins and don’t leave bowls out overnight. Fix leaky pipes and faucets, since even small water sources sustain a colony. Move bird feeders well away from the house, or take them down temporarily. Keep garbage cans tightly lidded, and clean up fallen fruit from trees in the yard. Reducing clutter in garages, attics, and basements also removes nesting material and hiding spots.
Trapping: The Safest First Option
Snap traps are the most effective and safest method for most home infestations. They kill quickly, let you confirm the catch, and don’t leave poisoned carcasses inside your walls. For mice, use standard mouse-sized snap traps. For rats, you need the larger rat-sized version. Placing a mouse trap for a rat won’t work.
Set traps perpendicular to walls with the trigger end facing the baseboard, since rodents travel along edges rather than through open space. Peanut butter is an effective bait because it’s hard for rodents to grab and run. Place traps every 5 to 10 feet along walls where you’ve seen droppings or other signs of activity. Use more traps than you think you need. For a moderate mouse problem, 12 or more traps in a single room isn’t excessive.
Check traps daily. If you’re not catching anything after two or three days, move them to new locations. Rodents can be cautious around new objects in their environment, so leaving traps unset but baited for a day or two before activating them can improve catch rates, particularly with rats.
Rodenticide Baits: When Traps Aren’t Enough
Poison baits make sense for large infestations or outdoor control around buildings, but they carry real risks and should be a second choice after trapping. If you buy rodenticide at a retail store, federal regulations restrict what’s available to you. Consumer products must be sold as blocks or solid bait (not loose pellets), limited to 1 pound of bait or less, and packaged with a tamper-resistant bait station. Second-generation anticoagulants, which are the most potent, are not sold to retail consumers at all and are restricted to licensed pest control professionals.
What you’ll find on store shelves falls into a few categories:
- First-generation anticoagulants: These deplete the body’s vitamin K supply, which prevents blood from clotting normally. Rodents need to eat the bait over several consecutive days for it to be lethal. Signs of toxicity may not appear until five days after exposure, so don’t expect immediate results.
- Bromethalin: A single-dose poison that shuts down energy production in nerve cells, causing swelling in the brain. Death can take anywhere from 8 to 12 hours to over a week after a lethal dose.
- Cholecalciferol (vitamin D3): This causes dangerously high calcium levels in the blood. Rodents need to eat multiple doses over several days. Organ damage, particularly to the kidneys, can develop within one to two days of toxic exposure.
Always place bait stations in locations inaccessible to children and pets. Never scatter loose bait. And be aware that poisoned rodents can die inside walls, creating odor problems that last weeks.
Risks to Pets and Wildlife
Rodenticide doesn’t just kill rodents. Dogs are commonly poisoned when they chew into bait stations or find unsecured packaging. Cats face a different risk: secondary poisoning. If your cat catches a mouse or rat that has eaten poison, your cat ingests that poison too. The same applies to wildlife. Owls, hawks, bobcats, and foxes that eat poisoned rodents accumulate toxins in their own bodies.
Anticoagulant poisons are particularly dangerous for secondary poisoning because a rodent can carry a lethal dose in its body for up to 10 days before dying, during which time it can be caught and eaten by a predator. This is one of the strongest reasons to use snap traps instead of poison whenever possible, especially if you have pets or live near open space.
Why Rodent Cleanup Matters
Rodent droppings and urine carry serious pathogens. Hantavirus pulmonary syndrome spreads when people inhale dust contaminated with dried mouse urine, droppings, or saliva. The most common risk factor for hantavirus exposure is rodent infestation inside the home. Leptospirosis, a bacterial infection that can damage the kidneys and liver, spreads through contact with infected rodent urine or contaminated water. Rat-bite fever and murine typhus are additional risks.
The critical rule for cleanup: never sweep or vacuum rodent droppings. This launches dried particles into the air where you can inhale them. Instead, follow this process:
- Open doors and windows for at least 30 minutes before you start. Leave the area while it airs out.
- Put on rubber, latex, or vinyl gloves.
- Spray droppings and urine with a bleach solution (1 part bleach to 10 parts water) or a household disinfectant. Let it soak for at least 5 minutes.
- Wipe everything up with paper towels and throw them in the trash.
- Disinfect any surfaces that may have been contaminated.
- Wash your hands thoroughly after removing gloves.
For large amounts of nesting material or droppings in enclosed spaces like attics or crawlspaces, wearing an N95 respirator adds an extra layer of protection against inhaling any particles that become airborne despite your precautions.
When to Call a Professional
A few mice in the pantry is a manageable DIY project. But if you’re hearing activity in multiple areas of the house, finding droppings in large quantities, or dealing with rats (which are more cautious, harder to trap, and can be aggressive), a licensed pest control operator has access to stronger tools. Professionals can use second-generation anticoagulant baits, conduct more thorough exclusion work, and identify entry points you might miss. They can also handle infestations in difficult spaces like crawlspaces, sewer lines, and commercial buildings where the scale of the problem outpaces what traps alone can manage.