The most obvious sign is seeing ants, especially if they are in large numbers. You might spot them along trails or in areas where they are searching for food, like the kitchen or pantry.

Ants leave pheromone trails that others follow. If you see a line of ants moving in a specific direction, it’s likely they are following a trail to and from a food source.

Some ants build nests indoors, often in walls, behind baseboards, or inside furniture. You may notice small piles of dirt, wood shavings, or other materials around these areas, which can indicate the presence of a nest.

Certain species of ants, like carpenter ants, produce winged swarmers (reproductive ants) during certain times of the year. Finding discarded wings around windowsills or other entry points is a sign that ants are trying to establish a new colony.

If an ant colony is large enough, you might hear a faint rustling noise inside walls or other structures, especially in quiet areas.

Carpenter ants, in particular, can cause structural damage by hollowing out wood to create their nests. You might notice small holes or frass (a mixture of wood shavings and ant droppings) near wooden structures.