Signs of rats in a house

Updated February 21, 2017

Rats invade houses in search of food, and oftentimes, they find it. These rodents cannot only devastate food supplies with their eating, but can also contaminate them simultaneously with their fur, faeces and urine. Rats can spread a variety of diseases and parasites that are harmful to humans, including salmonella, Weil's disease and perhaps most famously, the bubonic plague. Luckily, there are signs that can alert you to the presence of rats in the house, so you can then take appropriate action to remove them.


Rats can enter your home through a variety of different entry points. However, one of the most tell-tale signs that rats have made their way inside is the presence of holes. Specifically, according to the New York State Department of Health, these holes will be near the walls or foundations of your home and have freshly dug soil surrounding them. Even what you may consider to be tiny holes could be an indication of rats, as these rodents can squeeze their way into holes with dime-sized diameters.

Damage to various parts of the home

If you notice unusual patterns of damage to the bottoms of wooden doors or walls in your home, it could be a result of the gnawing of hungry rats. According to St Edmundsbury Borough Council, rats frequently gnaw or chew into objects with their two front incisor teeth. They do this to keep the teeth at a manageable length, as they grew continuously throughout their lives. Other items in the home that rats commonly gnaw on include lead and plastic pipes, the insulation from wires and cables and even brickwork.


In addition to leaving gnaw marks on items around a home, rats will also leave behind messes. During the search for food, they commonly scatter around trash, compost and any other waste products they happen to encounter.


Rat runs, or smears, are other good indicators that you have rats in the house. The runs are worn out pathways that rats leave behind in low vegetation, like grass, or on bare soil. They typically consist of continuous depressions on the ground, which are lined with dirt and grease. If you find a run leading up to, or into, your home, it is a strong sign that you have rats. Inside, you may be able to detect a run by observing footprints and tail-swipes that rats leave behind in dusty areas of your home.


Rat droppings are typically spindle-shaped, according to the St Edmundsbury Borough Council, and have rounded edges. The average individual dropping size is approximately two-fifths of an inch long. If you suspect that you may have a rat problem, try looking near food supplies and along walls for droppings. According to the New York State Department of Health, fresh droppings will be soft and dark in colour, and indicate that rats have been there very recently. Old droppings will be rigid and grey.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Erik Devaney is a writing professional specializing in health and science topics. His work has been featured on various websites. Devaney attended McGill University, where he earned a Bachelor of Arts in humanistic studies.