Skip to Content

Why is my house full of ants all of a sudden?

If you’ve noticed a sudden ant infestation in your home, you’re not alone. Ants invade over 30 million homes in the U.S. every year, especially during the warmer months. While ants are a nuisance, understanding why they may be entering and how to get rid of ants can help you take control of the situation.

What types of ants could be invading my home?

There are over 12,000 known ant species, but only a handful are known to infest houses. Some of the most common house-invading ants include:

  • Argentine ants: Small dark brown ants that trail along edges
  • Odorous house ants: Medium-sized black ants with a strong smell when crushed
  • Pavement ants: Small black or brown ants that build nests under pavement
  • Pharaoh ants: Tiny yellow or light brown ants, usually found in kitchens
  • Carpenter ants: Large black ants that can damage wood
  • Sugar ants: Tiny black or brown ants attracted to sweets
  • Thief ants: Tiny pale ants that nest indoors and “steal” food particles
  • Fire ants: Bright red ants with a painful sting, common in southern states

Identifying the type of ants invading can help you find and eliminate their nest. For example, carpenter ants chew through wood, so nest inspection should focus there if they’re the culprits.

Why are the ants entering my home now?

There are a few key reasons ants may suddenly enter a home in large numbers:

  • Weather: Ants are more active in warmer temperatures and look for food and water indoors.
  • Nearby nest: A mature ant colony nearby has reached capacity, causing winged ants to swarm and search for new nest sites.
  • Food and water: ants detect food or water sources inside the home.
  • Entry points: Cracks, holes, or gaps allow easy access for foraging ants.
  • Disrupted nest: Landscaping, construction, or heavy rain/flooding has damaged an outdoor ant nest, forcing them to find a new home.

Paying attention to when the ants appeared and locating their entry points can provide clues about their origin. Quick action also helps control ants before they multiply even more.

How are ants getting into my house?

Ants use a variety of secret passageways to enter homes, including:

  • Cracks in foundations and walls
  • Gaps around windows, doors, or pipes
  • Openings for wires, cables, and plumbing
  • Ventilation systems
  • Under siding or around the edges of doors/windows
  • Cracks in the sidewalk, driveway, etc. leading to the home’s foundation

Ants follow scent trails along edges, so pay special attention to cracks, crevices, corners, and other hidden areas. Track ant trails back to their entry point.

Where are the ants coming from outside?

Outdoor ant nest locations can provide clues about how and why ants are getting in your house. Ant species have different preferred nest sites:

  • Argentine ants: Under stones, landscape material, etc. Prefer moist soil.
  • Odorous house ants: Outdoors under rocks, wood, debris. Rotting wood is ideal.
  • Pavement ants: Under stones, cracks in pavement, beside buildings and sidewalks.
  • Pharaoh ants: Indoors in wall voids, basements, insulation. Don’t usually nest outdoors.
  • Carpenter ants: In wood including tree stumps, logs, telephone poles, sheds.
  • Thief ants: Often nest indoors in small spaces like woodwork or insulation.

Inspect likely nest sites within 30 feet of the house. A nest too close to the foundation increases the odds of ants entering your home.

How can I find where the ants are nesting indoors?

Finding indoor ant nest locations can be tricky but is key to elimination. Look for clustering ant activity in these common indoor ant nest spots:

  • Kitchen and bathrooms – under sink cabinets, near pipes
  • Attics and basements – in insulation, cracks
  • Wall voids and electrical outlets
  • Window and door frames
  • Furniture – under cushions, in drawers, or hollow legs
  • Potted plants
  • Behind walls – follow ants to locate nest entry point

Trails of ants on walls are the clearest giveaway to nest locations. Tap walls and listen for hollow sounds which indicate nests inside.

How can I get rid of the ants?

Getting rid of ants takes patience, diligence, and thoroughness. It often requires multiple integrated pest management (IPM) strategies to eliminate ants and prevent future infestations, including:

  • Inspecting thoroughly and locating all nests
  • Vacuuming ants and cleaning trails to remove scents
  • Sealing entry points with caulk, foam, weatherstripping, etc.
  • Eliminating outdoor food and water sources
  • Using boric acid or other ant bait treatments
  • Applying repellent chalk lines ants avoid crossing
  • Using ant killer sprays or granules where ants enter the home
  • Keeping kitchen surfaces clean and wiping spills immediately to avoid attracting ants

Work systematically through the home and yard to find and destroy all nests. Continue monitoring for ant activity and immediately clean up any new trails. Persistence and removing what attracts ants indoors will provide the best results.


Discovering ants invading your house can be upsetting. But now that you know some of the common reasons behind sudden ant infestations and key entry points to monitor, you can take steps to eliminate their food sources, nests, and access trails. Sealing up cracks, deploying ant baits, and doing regular inspections to prevent recolonization will help kick ants out of your house for good.