7 Signs Ants Might Be Living Behind the Walls

Ants don’t always march across the floor in neat little lines. Sometimes, they’re nesting behind the walls where you can’t see them—until the infestation gets serious. If you’re noticing these signs, there’s a good chance they’ve moved in where you don’t want them.

Rustling Sounds in the Walls

It’s faint, but if you hear a soft crackling or rustling coming from inside the wall, especially at night, ants could be tunneling through insulation or wood.

This is especially common with carpenter ants, who chew wood to make space—not eat it. Don’t ignore strange wall sounds.

Piles of Sawdust or Debris

If you’re spotting tiny piles of sawdust near baseboards, windows, or wall seams, ants might be tunneling behind the wall.

They push out debris as they dig. That powdery stuff isn’t from settling dust—it’s a sign they’re clearing space inside.

Ants Crawling from Electrical Outlets

Ants love warm, dark places—and outlets are a perfect entry point. If you see ants coming in or out of light switches or sockets, the nest might be behind the wall.

Turn off the power and check inside the plate. It’s not where you’d expect ants, but it’s a common hiding place.

Persistent Ant Sightings in the Same Spot

If ants keep showing up in the same room, even after cleaning or spraying, they’re probably nesting nearby. Surface treatments won’t fix it.

Watch where they disappear to—it’s often a gap in the wall, under trim, or behind appliances.

Sudden Swarms Inside the House

If you suddenly see dozens of ants—or flying ants—swarming a window or doorframe, it means the colony is mature and trying to expand.

They often swarm from wall nests. That’s your warning that it’s gotten serious.

Tapping on the Wall Draws a Reaction

Try lightly tapping near where you think they’re nesting. If ants start pouring out or reacting quickly, they’re likely living inside that section.

It’s not a foolproof method, but it works with carpenter ants and some common indoor species.

You’ve Treated the Room, But They Keep Coming Back

If you’ve sprayed, wiped, and sealed entry points, but ants keep returning, they’re probably already inside the walls.

That’s when it’s time to bait properly or call in a pro. If the colony’s inside your structure, surface sprays won’t cut it.

*This article was developed with AI-powered tools and has been carefully reviewed by our editors.