For the most part, ants live outdoors in underground nests. When seeking food, water, and shelter, ants can enter homes any tiny gaps that they find in the walls or foundation, drains, cables, and open doors. Ants also sneak in underneath garage and exterior doors, through gaps in windows, and any tears in screens on windows and doors. When scout ants find a food source in your home, they will emit a signal to their colony to follow them, so it’s important to take preventative measures before they make a home out of your house.