Fire Ants in the House

Finding fire ants inside your home is alarming, but it's not uncommon in the fire ant belt. Understanding why they come indoors and how to address it effectively will help you resolve the problem without making it worse.

Why Fire Ants Come Inside

Fire ants enter homes for the same reasons they go anywhere: food, water, and shelter from extreme conditions.

Extreme heat or drought: During summer heat waves or extended dry periods, fire ants may forage indoors seeking moisture and cooler temperatures.
Heavy rain or flooding: Rising water tables push colonies upward and outward. Ants displaced by flooding may enter homes at the foundation level.
Cold weather: In marginal climates, fire ants may seek warmth near foundations, under slabs, or inside wall voids during winter.
Food sources: Pet food bowls, crumbs, grease, and sugary spills attract foraging workers. Fire ants have extensive underground foraging tunnels that can extend from outdoor mounds directly into your home's foundation.

How to Trace the Entry Point

Follow the ants. Indoor fire ant trails usually lead to a crack, gap, or seam at the foundation, around pipes, along window frames, or where wires/cables enter the structure. Common entry points include weep holes in brick, expansion joints in concrete slabs, gaps around plumbing and electrical penetrations, and door thresholds.

Indoor Treatment

Immediate Steps

Remove food attractants. Clean up crumbs, seal pet food in containers, wipe down counters, and fix leaky faucets or pipes that provide water.
Kill visible ants with soapy water (dish soap and water in a spray bottle). This kills on contact without leaving chemical residue on food surfaces.
Seal entry points with caulk, expanding foam, or weatherstripping once you've identified them.

Targeted Treatment

Indoor-safe bait stations placed along ant trails. Products like Advion Ant Bait Gel can be applied in small dabs along baseboards, behind appliances, and near entry points. The ants carry the bait back to the colony outside.
Perimeter spray around the outside of the foundation. Apply a residual insecticide (bifenthrin or permethrin) in a 2-3 foot band around the base of the house and up the foundation wall about 12 inches. This creates a chemical barrier that kills ants crossing it.

Treat the Source

Indoor treatment alone won't solve the problem if the outdoor colony is still active. Walk around the exterior of your home and look for mounds near the foundation. Treat any nearby mounds using drenching or baiting. A broadcast bait application across your yard using the two-step method will address the larger infestation.

Never spray contact insecticides on indoor ant trails. This kills the visible ants but doesn't reach the colony, and it can scatter surviving ants into other areas of your home. Baiting is always more effective indoors because it targets the colony, not just the scouts. See why baits work.

Fire Ants in Walls or Under Slabs

If fire ants have established a colony inside wall voids or under your home's slab foundation, DIY treatment is difficult. Wall void colonies may require professional injection treatment. If you suspect an indoor nesting site (large numbers of ants emerging from inside the wall, especially with winged ants appearing indoors), it may be time to call a professional.