Signs of Mice in Your Apartment and Where to Look for Them

How to tell if you have mice in your property

Cat peering through a mouse hole at two mice hiding behind a wall
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Keeping a rental property free from pests is one of a landlord's main responsibilities. In fact, failing to do so can be a violation of government building and safety codes, so you could easily find yourself stepping afoul of the law. This isn't even to mention the damage that rodents can do to your property investment.

Mice might be tiny creatures, but they leave very clear signs, such as footprints and feces, when they've entered a home. Always keep a close eye on your property for the first hint of these pests because infestations can develop very quickly.

Know Where to Look

Mice don't hang out in the middle of rooms. They don't want to encounter you any more than you want to meet up with them, so watch out for signs off the beaten path.

A mouse will usually travel the perimeter of a room, so look for droppings along the baseboards. They particularly like corners where they feel safe, and mice like to relieve themselves in safe spots so you'll likely find droppings here, too. They'll leave oily marks on the walls if they've rubbed up against them in their travels.

Mice need water. They'll use leaky pipes as water sources, or they might even chew through plastic piping to get to the water inside. Check under the bathroom sink and the kitchen sink for damage.

Mice often build their nests near food sources, so look for holes, droppings, footprints, or gnawed bags in kitchens and pantries. Consider moving larger appliances like the oven or refrigerator away from the walls so you can inspect the areas behind them. Both tend to provide warmth and sometimes moisture, a pleasant environment for mice.

Mice often build their nests in basements or attics because they'll be undisturbed there. They'll climb along walls and pipes from these places to get to food sources in the main part of the house.

Signs That You Have a Mouse Problem

Mice are nocturnal, so you're not likely to come nose-to-nose with these little invaders at high noon—and, in fact, you really don't want to. Seeing them during daylight hours indicates that you might have a large population dwelling in the premises.

Mice will leave certain clues of their midnight travels, and you'll be able to see these in the daylight.

Like all creatures, a mouse will relieve himself after eating. The droppings will be small pellets, about ¼ inch long, with pointed ends.​ They're recent if they're shiny, and this means you have an active population in residence. The mice might have departed the premises if all the droppings appear dry and crumbled.

You probably have a whole family of mice if droppings seem to be of different sizes. This indicates that both adults and juveniles are relieving themselves.

As for urine, don't necessarily look for puddles. A mouse's urine will often mix with body grease, dust, and dirt to form solid-looking mounds up to two inches high.

You might be able to see footprints if the mouse walks through dust. These will usually be less than half an inch long.​

You might notice a hole in a wall or in molding. It doesn’t have to be large and, in fact, it probably won't be. Mice can fit through cracks as small as a quarter of an inch.​ They generally won't go to the trouble of gnawing a bigger hole when they can squeeze through that tiny opening just fine.

You or your tenants might be able to hear the mice traveling about in the walls, especially at night.​

Mice like to make nests out of soft material, such as insulation or newspaper. It could be home to these little critters if you find a pile of these materials.

You might notice a musky odor, or you might even be able to smell their urine. This will be especially noticeable if you have a large infestation.

It's very likely that you have more than one in your property if you see a mouse, either dead or alive. That lone mouse probably moved in with the whole family. Mice don't tend to travel alone.

Timing Is Everything

Always examine the premises for signs of mice when you first buy a property. It will be easier to see the problem and much easier to get rid of the rodents before you have tenants living in the unit.

Look for signs of mice when a tenant moves out. It will be easier to take care of the problem before the next tenant moves in.

Check out the situation immediately if a tenant complains of scratching noises, chewed bags, droppings, or about actually having seen a mouse.

Examine the pipe for signs of mice if you have PVC piping and experience a water leak. Mice are able to easily chew through these pipes if they aren't properly protected.​

How Do You Know It's a Mouse?

It can be difficult to determine if the rodent living in your property is a mouse or something else, such as a rat. Nonetheless, there are clues.

Mouse droppings are smaller in size. A rat's droppings will be larger, usually between ½ and ¾ of an inch.​

Mice also have smaller feet than rats. Their footprints will be about 3/8 of an inch long, whereas a rat will have a large foot, between ¾ and one inch. Rats also drag their tails, so you might find this type of disturbance in dust.