​​​​​​​​​​​​​​​​​​​​​​The house mouse has short hind feet and a tail that's as long as the head and body together. They’re usually a dark grey, but some house mice have light-brown backs with light-brown bellies. When fully grown, they weigh about 15 grams (0.5 oz.) and are 8 cm (3 in.) long.

A female house mouse will typically have 6 to 10 litters in her lifetime, with about 6 babies per litter. The house mouse lives for about 1 year.

How do house mice get into a home?

The house mouse usually enters a home in the fall and winter looking for food and shelter. They enter through holes or gaps in doors, walls, and foundations. A house mouse can squeeze through a crack as small as 1 cm (smaller than a dime).

You often realize that you have a house mouse because you see droppings (poop) near food, or under stoves, refrigerators, and sinks. You may also find holes in boxes and bags that have food or garbage in them.

What problems do house mice cause?

Mice cause damage by gnawing on insulation and building material, electrical wires, furniture, paper, clothing, and books. They contaminate (put germs on) food with their urine, hair, and droppings. Food can become contaminated with germs like salmonella. 

Mice can also carry fleas and mites. There is one species of mouse, the deer mouse, that is known to spread hantavirus.

How do I control house mice at home?

The best way to control a mouse infestation is with integrated pest management, which means using many methods at the same time. This includes:

• physical methods like traps
• chemical methods like poison

You can also call a licensed pest control operator, especially if the infestation is bad.

Keeping your house clean will help prevent mice from moving into your home. Once you know you have a house mouse, make sure to protect all food. Use glass or metal containers because mice can chew through plastic.

Mouse proof your home by using steel wool to seal openings and holes in and around:

• pipes
• doors
• windows
• walls
• foundations
• anywhere else mice could get in

How do I catch the mice?

Trapping is best when it's not safe to use poison baits. Don’t use poison baits around food, children, or pets.

Traps

There are several types of mechanical devices you can use to catch mice. Snap traps work well, causing an instant death. Make sure you bait and set the trap properly. Dried fruit, peanut butter, or marshmallows work very well as baits.

Another trap that works well is the ready-to-use glue board. When mice try to cross the board they become glued to the surface and eventually die. Glue boards are scented or can be baited (such as with peanut butter).

You can buy both types of traps in hardware stores. Put the glue boards and snap traps in corners and across the paths that mice use (mice prefer to travel around the edge of a room). Make sure you check the traps often.

Bait​

Most ready-to-use commercial baits have a product in them that damages the mouse’s blood vessels and doesn’t allow their blood to clot. The poison bait causes the mouse to dry up rather than rot. This means the dead mouse won’t smell as badly.

Place poison baits where only mice can get them. Keep poison baits out of reach of pets and children. Follow the directions carefully.

How do I handle a dead mouse or droppings?

Assume all mice carry disease. When you're cleaning up a dead mouse or trap, droppings or urine, and nests:

• Open windows and doors for 30 minutes to air out the area.
• Wear an appropriate, well-fitting filter mask, rubber gloves, and goggles. Appropriate masks include NIOSH-approved 100 series filters, such as N100, P100, and R100 (previously called HEPA filters), or a respirator with P100 cartridges. You can also use an N95 mask. Drug stores and hardware stores sell these masks.
  
• Don’t dry sweep or vacuum the droppings and nesting material as this might send germs (pathogens) into the air.
  

Follow these steps to clean up after dead mice, nesting material, and droppings:

1. Soak the mouse, nesting material, and droppings with a disinfectant or household bleach solution (1.5 cups of bleach per gallon of water or 1 part bleach to 10 parts water).
2. Clean up the area with a wet paper towel. Use latex or rubber gloves or use a plastic bag as a glove when cleaning up or handling any items.
3. Put the dead and trapped mice, nesting material, droppings, and cleaning material in a sealed plastic bag and put it in a garbage container outside. Before you take off your gloves, wash your gloved hands in the bleach solution.

​If you’re using a poison, read the label closely. This method works best when you also use physical control me​thods like traps.

When should I hire a professional?

If the problem is bad, it’s best to hire a certified pest control professional. Do your research and choose one you can trust.

The professional should be able to tell you what’s causing the pest problem and come up with a plan to get rid of the pest. They should do a full inspection of the home, inside and outside, to find and block the mice's entry points. The professional may need to make several visits, and it may take days or even weeks. Tell the professional if you have children or pets.

If you rent, your landlord must, by law, keep the home pest-free and hire a professional as needed. If your landlord doesn’t correct the problem, call the Safe Healthy Environments contact centre at 1-833-476-4743 to register a complaint for a health inspector.

To learn more, contact Safe Healthy Environments​.