Norway Rats in the U.S. Despite their international-sounding name, Norway rats are extremely common throughout the United States. They are what most people think of when visualizing a rat: sto cky rodents 12 to 18 inches long that weigh one pound and are brown to gray in color. The pests are found in every state. How Norway Rats Get in the House It is not unusual to find Norway rats in houses, as they have many skills at their disposal that make it easy to access a residence. These pests can gain entry by: Climbing exterior walls Jumping from trees Chewing their way through with their sharp teeth Contamination Having a Norway rat in the house can cause problems in multiple ways. It will contaminate groceries and pet food, which is a health hazard. Urine and droppings accumulate behind walls and in attics, fouling air quality and damaging wood. Damage Additionally, the pests have destructive habits that can cause structural damage, including gnawing on wiring and plumbing. Their chewing also damages wood, insulation, and siding. Norway rats gather in yards and can weaken foundations with their digging before they move into the house. Prevention For all these reasons and more, it is important to assert early control over infestations. When allowed to persist, rapid breeding can cause populations to swell. The professionals at Critter Control can remove Norway rats in the house and keep them from coming back.