Rat burrows can be found along foundations, or beneath rubbish and shubbery. If the burrow is active it usually clear of vegetation. Rat runways are smooth and well packed. Indoors, these runways are free of dust and dirt. They need water to survive, unlike mice.
Adults live about a year.
They live in colonies. The Norway rat generally prefers to live in underground tunnels. In the cities, they will be in the ground in their is available space, but have been known live entirely inside buildings. Rats will seek food outside, but many times will come inside at night to forage for food and return to their burrows. Needing a water source, they can obtain water from toilets, sinks, rain puddles, or condensation from utility pipes.