How to Get Rid of Mice in Your House: A Step-by-Step Plan

You are brushing your teeth, or maybe pulling a pan out of the cabinet, and you notice a few dark droppings that were not there yesterday. Or you hear a quick scratch inside a wall and then nothing. Most people feel two things at once: a little grossed out, and a strong urge to run to the store and buy something.

Before you do, it helps to know the order of the job. If you want to know how to get rid of mice for good, the order matters more than the product. This guide walks through it step by step, the same way we think about a rodent job at Pure Guard.

Do Mice Go Away on Their Own?

Almost never, and it is risky to wait and see. Mice stay where they have food, water, and a warm place to nest, and they breed quickly. UC Statewide IPM says a female house mouse may have 5 to 10 litters of about 5 or 6 pups each, so a problem that starts small does not stay small.

They also do not give up easily if you move them. UC IPM reports that house mice taken as far as a half mile from home can find their way back to their nest site. Releasing a live-caught mouse down the street is not a fix.

If You See One Mouse, How Many Are There?

Usually more than one. A single mouse that you spot in daylight or find in a trap is often just the one that was bold enough to be seen. Because of how fast they reproduce, it is safest to assume there are others until the traps and the evidence tell you otherwise.

WSU Extension lists the signs to look for: gnaw marks, droppings, urine stains, and grease smudges on walls. The more of those you find in different rooms, the more mice you likely have. Droppings in one corner of the garage suggest something different from droppings in the kitchen, the pantry, and the attic.

Step 1: Confirm It Is Mice

Mouse droppings are small and dark, roughly the size of a grain of rice, and they tend to show up in scattered clusters. Rat droppings are bigger. If you are not sure what you are looking at, our guide to mouse droppings versus rat droppings shows the difference side by side. It matters because the plan changes. Rats chew larger holes and are more cautious about traps.

Sound is another clue. Quick, light scratching and scampering, mostly at night, points to mice. Heavier thumping overhead points to rats. We cover that in mice or rats in the attic, and the in-wall version of the same question is in mice in the walls.

Step 2: Find How They Are Getting In

Every mouse in your house came in through an opening, and this is the step most people skip. If you trap without finding the openings, new mice replace the ones you catch.

So how do mice get in the house, and how small of a hole can a mouse fit through? The state health department says mice can squeeze through openings as small as a quarter of an inch. That is about the width of a pencil, so a gap you would never think twice about can be a front door.

Walk the outside of your home with a flashlight and look at these spots:

• Gaps around pipes, gas lines, dryer vents, and cables where they pass through the siding or foundation
• Cracks in the foundation and gaps where the siding meets the concrete
• Garage door seals, especially the bottom corners
• Torn or missing screens on attic and crawl space vents
• Gaps around doors, plus the hole left behind when a utility line was added

Then check inside. Look under sinks, behind the stove and dishwasher, and around the water heater for gaps where pipes enter walls. Mice also travel up inside walls. UC IPM notes they are excellent climbers and can run up any rough vertical surface, which is why a ground-level opening can lead to noises in the attic.

Step 3: Seal Every Opening

This is the step that actually ends the problem. The state health department recommends sealing small holes with steel wool and caulk, and using lath screen, metal, cement, or hardware cloth for larger ones.

In practice, sealing breaks down by the size of the gap:

1. Small gaps: Pack steel wool tightly into the gap, then cover it with caulk so it stays in place.
2. Larger gaps and vents: Use metal, such as hardware cloth screwed over the opening, or cement for foundation holes.
3. Check the materials: UC IPM says plastic screening, rubber, vinyl, foam, and wood are not effective for plugging holes, because mice chew through them.

One important caution: seal after you are confident the mice are out, or leave a spot open where traps are working. Closing a hole while a mouse is inside can leave it trapped in the wall. That is why we trap and seal as part of the same plan, not as two separate jobs.

Step 4: Take Away Food and Shelter

You cannot remove every crumb, but you can make your home a much less welcoming place.

• Store pantry food, pet food, and bird seed in hard containers with tight lids. Mice chew through cardboard and thin bags.
• Wipe crumbs and sweep floors, especially behind the stove and under the toaster.
• Take the trash out regularly and keep the can lidded.
• Clear clutter in the garage, basement, and closets. Piles of boxes and fabric make good nests.
• Move firewood, lumber, and stacked items away from the house.

UC IPM points out that house mice seldom venture more than 30 feet from their nest sites and food supply. That means the mouse in your kitchen likely has a nest close by, so it is worth looking in the spots around where you find droppings.

You may have also seen advice about peppermint oil and other strong smells. We looked at that in what smells do mice hate, and the short version is that a smell is not a substitute for sealing the house.

Step 5: Set Traps the Right Way

Once the entry points are handled, trapping removes the mice that are already inside. A few details make a big difference.

Choose snap traps. The state health department says glue and live traps are not preferred, because they keep the rodent alive. In general terms, a standard snap trap that is sturdy, sized for mice, and easy to set is a good choice. We are not going to name a brand, because most basic snap traps do the job when they are placed well.

Place them along the walls. UC IPM advises setting traps in secluded areas along walls, behind objects, in dark corners, and anywhere you see signs of activity. Mice tend to run along edges instead of across open floors. The DOH adds that the bait end should sit along the wall so it forms a “T” with the wall.

Use more than one. UC IPM suggests spacing traps no more than about 10 feet apart in areas where mice are active. Set several in each busy area rather than a single trap in the middle of the room.

Bait lightly. The best bait is often the food the mice are already eating, and UC IPM suggests a small amount, or a bit of cotton or dental floss as nesting material.

Keep pets and kids safe. Place traps where children and pets cannot reach them, such as behind appliances or inside a covered box.

Check the traps every day. Mice are most active at night, so the morning is when you will usually find out whether you caught something.

What About Poison?

We skip it inside the home. The state health department notes that poison baits can be a problem because the rodent can die somewhere you cannot reach, and they can be eaten by pets or tempt small children. A mouse that dies inside a wall also means a smell you will notice for a while.

Step 6: Clean Up Safely

Droppings and nests can carry germs, so do not just grab a broom. The state health department says not to vacuum, sweep, or stir up dust around rodent contamination. Instead, wear gloves, wet the droppings and nests with a 10 percent bleach solution, wipe them up with paper towels, and air out the space for at least 30 minutes first.

Our droppings guide has more on identifying what you are cleaning up. Deer mice are the main hantavirus carriers in Washington, which is another reason to keep the dust down. If you ever feel unwell after cleaning up rodent droppings, talk with a doctor and mention the exposure.

Step 7: Follow Up

A good plan does not end when the last trap is empty. Keep a few traps in place for a week or two after the last catch, and keep checking them. Then walk the outside of the house again and look at your seals.

If new droppings keep appearing, there is another opening you have not found yet. Look again at the garage, the crawl space, and the roofline. For the garage in particular, see how to keep mice out of the garage. And if the activity is heavy and overhead, rats may be the better explanation for what you are hearing.

How Long Do Mice Live?

UC IPM says a house mouse usually lives 9 to 12 months, although some have lived up to 3 years. That sounds short, but the same mouse can produce many litters in that time. Waiting for them to die off is not a plan.

When to Call a Professional

You can handle a single mouse yourself. Call someone if droppings keep returning after you have sealed what you found, if you hear scratching in the walls or ceiling, if you cannot find where they are getting in, or if the activity is in places you cannot reach safely. The state health department also suggests contacting a pest control company when an infestation is severe.

Our rodent control service follows the order in this guide. We look for the entry points first, seal what we find, and trap inside the home. We use trapping rather than bait indoors. Someone is out within 48 hours, and you get a text about 30 minutes before the truck arrives. We are licensed by the WSDA (license #112338) and family-owned in Lake Stevens.

We also have local pages with more detail for Everett, Lynnwood, Edmonds, Woodinville, and Snohomish. When you are ready, request an inspection and tell us where you have seen droppings or heard noises.

If this is happening at your place, our local pages cover what the work looks like in each of our core markets: rodent control in Lake Stevens, Lynnwood rat control, rat and mouse control in Edmonds, rodent control in Woodinville, and Everett rat control.