Rat and mouse articles · Updated
Do rodent repellents work?
Repellents don't solve a rodent problem. Rats and mice get used to sounds and smells, and nothing you plug in or spray closes the gap they're using. Trapping the rodents inside and sealing the entry points is what works.
It's tempting to plug something into the wall and be done. Repellents are sold everywhere, and some smell nice. But a rodent that has found food, water and a warm attic has a strong reason to stay, and a repellent doesn't change any of that. Here's a look at the common ones and what to do instead.
Ultrasonic plug-ins
These emit a high-pitched sound people can't hear. The problems are practical. The sound doesn't pass through walls, furniture or insulation, so it doesn't reach the attic or wall voids where rodents live. Rodents can also get used to a constant sound. And it does nothing about the gap they're coming through. Pest control providers don't rely on them, and neither should you. If you already own one, it does no harm to leave it plugged in, but don't let it stand in for traps and sealing.
Peppermint oil and other scents
Cotton balls soaked in peppermint oil are a popular home remedy. The smell fades within days, it doesn't reach into wall voids and attics, and a hungry rodent will put up with it to get to food. If you like the smell, it does no harm. It won't fix a rodent problem.
Something in the attic or the garage?
Want a local rodent technician to look at it? Same-day appointments are often available. (972) 325-9652
Mothballs
Mothballs are a pesticide meant for sealed containers of clothing. Scattering them in an attic, garage or car isn't how they're labeled to be used, and the fumes aren't something you want in a living space or a closed garage. Skip them.
Dryer sheets, steel wool balls and other tricks
Dryer sheets in the engine bay or the garage are a common tip. There's no good reason to expect them to work, and they can become nest material. Steel wool is different: packed into a gap and sealed over, it's a barrier, not a repellent. The steel wool vs. copper mesh article covers how to use it.
Predator urine and cats
Predator scents fade, and rodents get used to them. A cat may catch a few mice, but it won't close the gap they're coming in through, and it can't reach the attic or the walls. A cat is a pet, not a plan.
Repellents in cars and garages
Garages and parked cars are where people try repellents most: peppermint pouches under the hood, dryer sheets on the shelves, a plug-in by the door. A garage is open to the alley every time the door goes up, and rodents come and go with it. A tight door seal, food in metal cans and traps along the walls do far more. The rodents in the car article covers vehicles.
What works instead
Three things, in this order:
- Remove food and water: seed and pet food in metal cans, fallen fruit picked up, leaks fixed
- Trap the rodents already inside, with snap or electric traps along the walls
- Seal every gap with metal: hardware cloth, flashing, copper mesh with sealant
Why the gadgets are popular
Repellents are easy. You buy one, plug it in, and it feels like you've done something. They don't require going into the attic, getting on a ladder or handling a dead mouse. That's the whole appeal, and it's also why they don't work on their own. The hard parts of rodent control are finding the gaps and dealing with the rodents already inside.
Cheap things that do help
If you want to spend a little money, these do more than any repellent:
- A new garage door bottom seal
- A roll of copper mesh and a tube of exterior sealant
- Weep vent covers for open weep holes
- A dozen snap traps
- Metal cans with tight lids for seed and pet food
- A tree trimmer for branches over the roof
What a provider does instead
A good provider doesn't sell repellents as the fix. They inspect the attic, the garage and the roofline, trap the rodents inside, close every gap with metal and come back to confirm it worked. If a company recommends an ultrasonic device as the main plan, get a second opinion. The same goes for a plan that's only bait stations around the outside with nobody looking in the attic. Ask what entry points they found and how they'll close each one.
Why sealing beats repelling
Texas A&M AgriLife training material says a mouse needs about a quarter-inch crack and a rat about half an inch. Every one of those gaps is a door. A repellent asks the rodent to choose not to use it. Sealing takes the choice away. In Plano houses, the usual gaps are the garage door seal, the AC line set, open weep holes and the roofline. The entry points article walks through them.
If you've tried repellents and still hear noises, it's time for entry point sealing and trapping. A rodent inspection finds the gaps.
Something in the attic or the garage?
Ready to have the gaps found and closed? Call and describe what you're hearing or finding. (972) 325-9652
Common questions
Do ultrasonic devices work in the attic?
The sound doesn't travel through insulation and framing well, and rodents get used to it. Trapping and sealing work better.
Is peppermint oil safe around pets?
Some concentrated plant oils can bother pets, especially cats. Ask your vet before using concentrated oils around animals.
Will a cat keep mice away?
A cat may catch a few, but it won't stop new ones coming through an open gap.
Are there any repellents worth buying?
Spend the money on traps, door seals and hardware cloth instead.
Do natural repellents hurt rodents?
Most just smell strong. They don't remove rodents or stop new ones from coming in.