The fastest way to get rid of ants in your house is to set out bait that matches the species you’re dealing with, then cut off the food and water sources that attracted them. Killing the ants you can see does almost nothing. The colony, which can number in the tens or hundreds of thousands, keeps sending more workers. Bait works because foraging ants carry the slow-acting poison back to the nest, killing the queen and collapsing the colony from the inside out.
Identify What You’re Dealing With
Not all ants eat the same things, so the wrong bait will sit untouched. A quick look at the ants on your counter tells you a lot. The most common indoor species are small (about 1/8 inch), dark colored, and attracted to sweet foods. These are usually odorous house ants, named for the rotten coconut smell they release when crushed. If you see tiny orange-brown ants near greasy food, you likely have thief ants, which prefer fats and proteins over sugar. Pavement ants are reddish-brown to black, also about 1/8 inch, and will eat just about anything: sweets, grease, or protein.
Carpenter ants are the ones to watch for. They’re noticeably larger, 1/4 to 5/8 inch long, and typically black. They don’t eat wood like termites, but they hollow it out to build nests, especially in areas where wood stays moist. If you’re finding coarse sawdust-like shavings (called frass) near baseboards, window frames, or wall voids, carpenter ants may be causing structural damage. They require a different approach than the smaller species.
Choose the Right Bait
Bait is the single most effective tool for eliminating an ant colony. The key is matching the bait type to what the ants are eating.
- Sweet-feeding ants (odorous house ants, Argentine ants, carpenter ants): Use liquid or gel baits with a sugar base. Borax-based liquid baits, like the widely available Terro stations, use a 0.5 to 1% borate solution in sugar water. These are effective and inexpensive.
- Grease-feeding ants (thief ants, pharaoh ants): Use protein or fat-based solid bait stations. Sugar baits won’t attract them. Products containing fipronil or hydramethylnon in protein formulations work well.
- Ants that eat everything (pavement ants): Try both sweet and protein baits side by side and see which gets more activity.
Place bait stations directly along the ant trails you see, near entry points, and close to where ants are congregating. Don’t spray insecticide near the bait. You want ants to find it, feed on it, and carry it home. Expect to see more ants initially as scouts recruit nestmates to the food source. That’s a good sign. Individual ants die within 24 to 48 hours of eating the bait, but full colony elimination takes anywhere from a few days to several weeks depending on colony size.
Why Sprays Usually Backfire
Spraying a line of ants with contact insecticide feels satisfying, but it’s one of the least effective long-term strategies. You kill a handful of foragers while the queen keeps producing thousands more. Worse, spraying can scatter the colony. Some species respond to insecticide exposure by “budding,” splitting into multiple smaller colonies in different locations around your home. This turns one problem into several.
If you want to use a spray at all, limit it to sealing entry points. A residual perimeter spray along the outside foundation of your home can deter new ants from entering. But indoors, bait is almost always the better choice.
Dealing With Carpenter Ants
Carpenter ants are harder to eliminate than most species. They have a varied diet, so standard sweet baits often don’t attract enough workers to collapse the colony. Spraying individual foragers is also largely ineffective, since the colony remains unaffected.
The most reliable approach is finding the nest and treating it directly. Carpenter ants prefer moist or water-damaged wood, so start by checking areas with past moisture problems: around leaky windows, under bathroom sinks, near roof leaks, and where plumbing runs through walls. A moisture meter can help pinpoint problem areas behind drywall. Look for small piles of wood shavings, rustling sounds inside walls, or large winged ants emerging in spring.
If you can’t locate the nest, specialized carpenter ant baits exist, though results are less consistent than with other species. For an active carpenter ant infestation, especially one in structural lumber, professional pest control is worth the investment.
Diatomaceous Earth as a Non-Chemical Option
Food-grade diatomaceous earth (DE) is a fine powder made from fossilized algae that damages the waxy outer coating on insects, causing them to dehydrate and die. It works purely through physical contact, not chemical action, which makes it a reasonable option for homes with young children or pets.
Sprinkle a thin layer along ant trails, baseboards, windowsills, and under appliances. Vacuum it up and reapply every few days until you stop seeing ants. DE won’t eliminate a colony the way bait does, since it only kills ants that walk through it, but it’s useful as a supplemental barrier at entry points. Wear a dust mask during application. The fine particles can irritate your lungs if inhaled. Only use food-grade DE. Pool-grade diatomaceous earth is chemically treated and harmful.
Cut Off Food, Water, and Entry Points
Bait eliminates the current colony. Prevention keeps the next one from moving in. Ants are searching for two things: food and moisture. Remove both, and your home becomes far less attractive.
Clean up crumbs and spills immediately, especially sugary liquids. Store pantry items like sugar, honey, cereal, and pet food in sealed containers. Take out trash regularly and keep bins clean. Rinse recyclable cans and bottles before storing them. Fix dripping faucets, leaky pipes, and any areas where condensation collects. Ants are remarkably resourceful at finding water, and a slow drip under a sink can sustain a colony for months.
For physical exclusion, seal cracks and gaps where ants enter. Common entry points include gaps around window frames, door thresholds, where pipes or wires penetrate walls, and cracks in the foundation. Silicone caulk works for most of these. Outside, trim tree branches and shrubs so they don’t touch the house. Branches serve as highways for ants moving from outdoor nests into your home. Replace any water-damaged wood around the exterior, and make sure mulch or soil doesn’t directly contact wood siding or framing.
When to Call a Professional
Most ant problems respond to baiting and sanitation within a few weeks. But some situations justify professional help. Carpenter ants nesting inside walls or structural wood can cause real damage if left untreated, and locating their nests often requires specialized tools and experience. Pharaoh ants are another notoriously difficult species that bud aggressively when treated incorrectly, making DIY efforts counterproductive.
You should also consider professional treatment if ants keep returning after multiple rounds of baiting, if nests are in hard-to-reach locations like under flooring or inside wall cavities, or if you’re dealing with a large-scale infestation that doesn’t respond to store-bought products. Costs vary based on the severity of the infestation, the species involved, and your home’s size, but most services include follow-up visits to ensure the colony is fully eliminated.