How to Mouse Proof Your House

It usually starts slow. You might see a random mouse here or there. Perhaps the cat proudly shows a kill in the garage. Then you see one run across the kitchen.

With mice, typically where there is one, there are many, so if their presence is known, it’s time to get aggressive. Even if you haven’t seen the stealthy rodents, they may be around, and it’s best to keep them entertained somewhere other than inside your home. Take action to keep them at bay for a healthier, damage-free home.

Problems with Mice

For such a small creature of nature, mice can certainly create big problems.

Perhaps the biggest issue is the potential for spreading disease. That’s right. Those arguably cute little critters can make your family sick. Mice can carry dozens of diseases, which are spread through urine, feces, and saliva.

That means the mice don't even need to touch you to make you sick, making it important to remove them from the home and keep them away.

Commonly mouse-spread diseases include hantavirus, salmonella, and rat-bite fever. If you have mice in the home and experience symptoms such as fever, headaches, diarrhea, vomiting, rash, dizziness, or swollen lymph nodes, mention the mice when you go to the doctor.

Signs of Mouse Activity

How do you know if there are mice in the house if you haven’t seen any? Mice are very secretive. They would much rather remain unseen and out of your way. So even if you don’t see them scurrying around, there’s evidence of their activity.

Watch for feces. The easily identifiable little black droplets are often in drawers, on shelves, along window sills, and near baseboards. Your attic, basement, or closets may be littered too.

They urinate too. You may not know what you’re looking for, but if you find an entry point, you’ll see the telltale signs of both feces and urine. After time, the collection of urine and fur creates small mounds known as urine pillars. Mouse urine also emits a smell similar to ammonia. If you’re wondering where the smell is coming from, mice might be to blame.

Listen up. You will often hear mice chewing or scraping in the walls or the attic. You may also hear the scurry of little feet as they run around above your head.

Grease rubs. Mice develop an oily coating on their fur that is transferred to surfaces inside your home. They often take the same route repeatedly to food sources or exits. Over time, the oil creates a mark along walls, furniture, or doors.

Identify shredded materials. If you open a drawer to find confetti stashed in the back corner, mice are at work in your home. They commonly use paper as a nesting material. Even if you don’t find a nest, you may see papers, packaging, or magazines with nibble marks where they’ve been collecting materials for their nest.

Watch for tracks too. If there is any dust or other powdery substance on the floor or counter, you may be able to see mice footprints. The tail also leaves a telltale clue as they run along.

Do you have other pets? If so, they will likely alert you to rodents in the house. If your dog or cats appear to be obsessed with the wall behind a socket or a pot in the corner of the room, they're likely aware of rodents they can smell and hear.

Additionally, you may see gnaw marks on wood or other materials in your home. Cabinets, trim, carpet, rugs, or wires to your electronics may be their victims, letting you know of their presence.

Find the Source

If you already have mice in the home, it’s crucial you find the entry points. It’s important to note that mice can enter the home through a hole as small as a pencil eraser. Unless you see mice coming and going, it can be difficult to figure out where they’re gaining access.

Follow the clues above to see if you can find them. For example, watch for nests. Look for an area with a large amount of feces and urine, especially in areas such as the garage, basement, or unused rooms.

Keep Mice at Bay

If you’ve seen them, or evidence of them, it’s time to eradicate them. If they haven’t yet taken refuge in your home, it’s still a good idea to take preventative measures.

Note that mouse activity is particularly common as the cold weather rolls in and rodents look to relocate to warmer areas, such as your home. They’ll want to come indoors, and they’ll look for any invitation to do so. There are many ways you can deter them, though.

Step 1 - Clean Thoroughly

There’s just no substitute for a clean and tidy house when trying to keep the mice away. Clutter, especially paper products, is an invitation for mice to shop for housing materials.

Avoid stacks of paper, books, and magazines, especially near walls. Instead, use shelving, especially shelves off the floor where mice are less likely to visit.

Access to food is the primary draw for rodents. Don’t make it easy for them. Pick up and properly dispose of all food packaging and other garbage. Tightly seal food products in storage containers. Also store grains and cereals (their favorite foods) on higher shelves.

Even small crumbs provide an enticing meal for mice, so keep counters and floors free of food debris with regular cleanings.

If mice discover food sources are hard to come by, they’ll quickly move on to better options.

Step 2 - Select the Right Cleaning Products

In addition to keeping the house clean, the cleaning products you use may deter them further. Choose a cleaner that contains ammonia, for example. These options deter mice because they smell like urine, which can make them think other predators are in the area.

Mice are also repelled by the scent of strong-smelling herbs, so they find cleaners with an aroma of cloves, peppermint, cayenne, or lavender uninviting. Use these cleaners on countertops, but also along floor trim and beneath cabinets where mice like to route paths.

Step 3 - Sprinkle Scents

In addition to your cleaning products, up the unpleasant scents by sprinkling cloves or cayenne pepper in problem areas.

Where it’s not convenient to sprinkle spices or leave sprigs of fresh mint, use scented oils instead. Apply the oils to cotton balls and place them in drawers, closets, or gaps in the trim, door jambs, or siding.

Cinnamon is another effective deterrent that can be sprinkled or left in open containers inside cabinets. It can also be put into sachets in powder form or wrapped cinnamon sticks.

You can also spray scents, such as vinegar. It’s not a smell most humans like either, but vinegar is safe for most applications, meaning it won’t harm your home’s surfaces. Create a mixture of vinegar and water and spray areas where you suspect mouse activity.

Let dryer sheets help you out too. You can stuff them into gaps or simply lay them in furniture, cupboards, or drawers. They will lose their scent after a week or two, so replace them as necessary.

Step 4 - Seal Openings

By far the number one most effective strategy for preventing mice from entering your house is to seal up every opening they may take advantage of. Start with the largest gaps or cracks in wood, concrete, drywall, and other materials around the home. Fill or patch them with the appropriate materials and techniques.

Then start looking for smaller, and even tiny, gaps. There are a variety of effective sealants to keep mice out. Around doors, windows, and bathtub walls, use caulking to fill any openings.

You can also use small amounts of caulking at the bottom of cabinets, where pipes enter the home and leave an opening, or around plumbing pipes or gas lines. These are just a few areas mice can squeeze in, but they are common culprits to look for.

In addition to caulking, steel wool makes an excellent hole filler. It’s one of the only things mice won’t chew through. Use it generously anywhere you see a potential opening into the home.

Also note mice are very opportunistic in their dedication to entering your home. They’ll take advantage of an opening in the plumbing to pop up in your sink drain or shower. They’ll scurry through the ductwork if they find a small crack to enter around the furnace in the garage or through a vent to the outside of the home.

With this in mind, walk around the exterior of your home, identifying and stuffing any potential entry point.

The chimney can be an opening too, especially when it’s not in use. Add a protective chimney cap to keep them out. This will also keep you from dealing with birds and other small animals in the chimney.

Step 5 - Get a Security Guard

While not all cats are great hunters, most are by instinct. Even if they don’t kill mice, they will at least point them out and traumatize them by trapping them and toying with them. Mice would definitely prefer a home without cats to worry about.

Outside your home, predators can help too. Encourage birds, especially larger birds such as hawks, falcons, and owls, to hang out around your home. Other ground animals feed on mice as well, so don’t be too hard on ferrets, snakes, and foxes.

Step 6 - Install Mouse Traps

Nobody really wants to deal with mouse traps, but they are an effective (perhaps the most effective) method for ridding yourself of the little rodents. There are many different kinds of traps to consider.

If you prefer a live trap, be sure to check it daily. While poison is an option, you’ll commonly create another problem for yourself by finding dead rodents around the house.

Plus, poisons transfer to animals that may feed on the mice before they die. So attempting to target a mouse may inadvertently sicken or kill predatory birds and other animals.

The best option is the most simple--a basic mouse trap. They’ve been around forever, and are inexpensive, easy to find, and easy to use.

Set your traps with peanut butter rather than cheese. Mice are pretty good at swiping the cheese and escaping the trap. With peanut butter, they are likely to stick around licking the substance and trying to figure out how to transport it. Fatal demise.

Place mouse traps away from areas where your other animals can get to them. Put them in areas where you’ve seen mice or evidence of mouse activity. In each space, place the trap up against the wall or side of a cabinet or drawer.

Mice move about the house by using their whiskers as a guide. Inasmuch, they stay close to surfaces where they can keep those whiskers in contact, such as walls. They rarely run across the middle of the room, so put the trap in their path.

Also check these traps often. You’ll want to dispose of the mouse and get the trap reset as soon as possible.

It’s a good idea to keep some traps set at all times, even if you haven’t recently seen any indicators. Put one in the back of the cabinet beneath the sink and behind the dryer in the laundry room. Put one behind the large bookcase in the living room and a few in the garage.

A Note About Safety

Since mice carry disease, it’s important to deal with them properly. While it’s very rare for a mouse to bite a human, it’s best not to handle them at any time if possible. The bigger concern is actually the passive transfer of disease.

While the presence of feces and urine is unpleasant, disturbing it feeds the transfer of disease. So if you hear or see mice in your ductwork, do not turn on your air conditioning or heat until you have the ductwork professionally cleaned. The air can disturb droppings in the HVAC system and blow viruses directly into each room.

While cleaning up areas of feces or urine, wear a mask and gloves.

Mice are quick, stealthy, and destructive. But they’re not the only pests that put your home at risk. Check out Combating Cool-Weather Pests and consider how to Repel Pests With Plants for more information.