Ant colonies are generally found in any of the following locations: soil, wall cavities, timber, roof voids or under pavement. They'll often travel long distances to find food, and even the cleanest of places might be a viable source of food for them.
Carpenter ants are wood destroying insects and, over time, can do serious structural damage to a building. They do this by hollowing out wood to make nests. They do not eat wood, as termites do. Consequently, you may find sawdust piles near carpenter ant nests. Very often excess moisture is the cause of ant infestations. Leaking pipes, leaf piles against the structure or poor drainage may attract ants to your home.
A FREE NPWC inspection will help determine the source of the problem as well as the best course of action to remedy the situation.