7 Signs of a Rodent Infestation in Your Home

Droppings are usually the first thing people notice, and they're the most reliable clue you'll get. Mouse droppings look like small dark grains of rice, roughly a quarter inch long and tapered at both ends. Rat droppings have the same shape but run bigger, up to about half an inch.

Check where rodents like to travel and feed: under sinks, inside cabinets and pantries, in the garage, the attic, the crawlspace, the basement. Look around air vents and pipes too, and near any hole in a baseboard, wall, or floor. Fresh droppings are dark and a little soft. Old ones turn gray and crumble. That difference tells you how active the problem is right now.

A rodent's front teeth never stop growing, so it gnaws constantly to keep them worn down. That habit puts drywall, paneling, wood, wiring insulation, and food packaging on the menu. Rats go further and can work through soft mortar and tougher materials.

Look for chew marks on door corners, baseboards, and cabinet edges, and check the food boxes and bags in your pantry. Gnawed wiring is the find that should worry you most. It's a fire hazard, and it tells you rodents are moving through your wall and ceiling voids.

Rodents build nests from soft, shredded material in quiet spots nobody disturbs. They'll use paper, cardboard, insulation, fabric, dried plant matter, anything they can pack into a loose ball.

The likely hiding places: inside wall voids, behind or under appliances, in storage boxes and drawers, in attic insulation, and in the cluttered corners of a garage. Find a nest and you've found breeding. These rodents aren't passing through. They've moved in.

Rodents carry body oils that rub off as they squeeze along the same routes night after night. Those smudges build up into dark, greasy streaks along baseboards, around holes, and at the edges of the beams and pipes they use.

Because they travel the same paths over and over, a rub mark works like a map. It shows you where they get in and roughly where the nest sits, which makes it far easier to place traps and seal the right gaps.

Rodents do most of their moving around at night, so you'll often hear them before you ever see one. After dark, listen for scratching, scurrying, squeaking, gnawing, or chattering inside walls, ceilings, and the attic.

Activity tends to spike during storms, when rodents push indoors for shelter. As a population grows, you may also catch higher-pitched squeals or shrieks. That's the sound of territorial fights.

Rodent urine builds up into a sharp, musty ammonia smell. You tend to notice it when you open a cabinet that's been shut for a while, or step into the attic. Near an active nest, some people pick up something closer to corn chips, popcorn, or stale grain.

That odor is more than a nuisance. Dried urine and droppings can break down into airborne particles, and the bacteria rodents carry are a big reason a strong, lingering smell deserves a quick response.

Spotting a live mouse or rat, even once, is the most direct sign there is. It almost never means a lone intruder. Rodents hide well, so a daytime sighting or a mouse darting across the floor usually points to an established group nearby. See one, and you should assume there's a nest in or around your home. Then go looking for the other six signs to figure out how big the problem really is.

Any single sign on this list means it's time to act. Several together mean a real infestation. Start with the basics: clear away food sources, cut down clutter, and seal the obvious entry points. Just don't count on traps alone to fix a problem that's still growing.

A licensed local pro can confirm the species, find the hidden nests and entry points, trap the right way, and seal your home so rodents can't come back. Then they monitor to make sure it stays that way.