How to Get Rid of Ants in the House (and Keep Them Out): The Argentine Ant Playbook
The ants in a San Gabriel Valley kitchen are almost always Argentine ants, part of a colony that spans the block. That changes what works. Here is the plan that does.
To get rid of ants in the house, stop spraying them and feed them. Argentine ants, the 1/8-inch dull-brown ant in nearly every San Gabriel Valley home, live in a linked supercolony with many queens, so killing the trail you can see does nothing to the nest. Wipe the trail with soapy water, take away food and water, and place slow-acting sugar baits where the ants are entering and along the foundation outside, every 10 to 20 feet. Expect more ants at the bait for a day or two, fewer in five to ten days, and real relief in a few weeks; refresh the baits and do not spray while they work. Then caulk the gaps, keep plants and mulch a foot off the foundation, and fix the drips. Repellent sprays kill foragers, split colonies and can trap ants indoors, which is why the ants come back worse.
Local help: Argentine ants in the kitchen? Text a photo of the trail to (626) 409-1584 and we will tell you whether baiting at home will handle it or whether a one-time visit makes sense. Quotes from photos are free.
On this page
- Why ants come back after you spray
- Ant traps vs. ant baits: what the words actually mean
- How to get rid of ants in the house: the 10-day plan
- What is the best ant bait? Active ingredients, speed and form
- Where to put ant bait (and where not to)
- How to keep ants out of the house for good
- Ants in the kitchen, the bathroom, after rain and in a heat wave
- When DIY ant control is not enough
- Sources
- Quick answers
Why ants come back after you spray
The Argentine ant is the most common house and garden ant in California, a dull-brown worker about 1/8 inch long. Its colonies do not fight each other; they link into a supercolony with many queens and shallow nests that run under sidewalks, planters and foundations for blocks. The trail in your kitchen is a thread of that. Spray it and three things happen, all documented by UC IPM: the foragers die and are replaced within hours, the colony is untouched because the queens never left the nest, and if you sprayed a barrier, ants already inside are now trapped in the house with you. Perimeter sprays with pyrethroids also wash into storm drains, which is why California has limited their use around foundations. The long version is in why ants come back after spraying.
Ant traps vs. ant baits: what the words actually mean
People search for ant traps; what works is ant bait, and the plastic stations sold as traps are bait stations. The difference matters. A bait is food laced with a slow-acting toxicant that foragers carry home and share, so the dose reaches the queens and brood over days. UC IPM puts it plainly: the pesticide must be slow-acting so workers are not killed before they get back to the nest. A sticky trap catches a few foragers and does nothing. A contact-kill station is a spray in a box.
| Method | What it kills | Reaches the queens? | UC IPM verdict |
|---|---|---|---|
| Contact spray on the trail | The foragers you can see | No | Usually unnecessary indoors; will not prevent more ants from entering |
| Perimeter spray around the house | Foragers crossing the band | No | Kills foragers, not the colony; ants rebuild and return; pyrethroid runoff pollutes waterways |
| Vinegar or soapy water on the trail | Nothing; erases the scent trail | No | Fine for cleanup of a trail, not a control |
| Prepackaged bait stations (borate, about 5 percent) | Foragers and, over time, the nest | Partly | Works for household foragers; weak against major infestations |
| Liquid borate sugar bait in refillable stations (0.5 to 1 percent) | The colony, over weeks | Yes | Recommended for severe Argentine ant problems; several days to a week to see results |
| Station baits with fipronil, hydramethylnon or abamectin | The colony, over weeks | Yes | Effective slow-acting choices when the ants accept the food |
| Granular contact products (cyfluthrin, permethrin) | Foragers on contact | No | Not baits; avoid for ant control |
How to get rid of ants in the house: the 10-day plan
- Day 0, morning: stop spraying. Anything repellent near the trail will keep ants off your bait for days.
- Day 0: wipe the trail and take away the food. Soapy water on the counters and baseboards erases the scent trail. Seal food, rinse recyclables, pick up pet bowls between meals, fix the dripping faucet and the sprinkler head that soaks the foundation.
- Day 0: place bait on the trail. Sweet liquid or gel bait where the ants enter and along their route, and outdoors at trail and nest openings along the foundation, every 10 to 20 feet, in shade. Sugar baits attract Argentine ants year-round; protein baits mainly in spring. If they ignore one, offer the other.
- Days 1 to 3: expect a crowd. More ants at the bait means recruitment is working. Do not kill them. Top off the stations.
- Days 5 to 10: fewer ants. UC IPM’s timeline. Keep the bait fresh; dried or rancid bait stops being taken.
- Weeks 2 to 4: colony pressure drops. Now caulk the entry points you watched them use, and start the sealing-and-starving steps below.
- Late winter next year: bait early. The most effective and economical time to bait is late winter to early spring, before numbers climb.
What is the best ant bait? Active ingredients, speed and form
Match the food first, then the active ingredient. Argentine ants are sugar feeders most of the year and switch toward protein when they are raising brood in spring, so a bait they ignore is usually the wrong food, not the wrong poison. We do not name brands anywhere on this site; read the active ingredient on the label.
| Active ingredient | Speed | Usual form | Notes from UC IPM |
|---|---|---|---|
| Borate / boric acid | Slow | Liquid or gel sugar bait; prepackaged stations | Low concentrations (0.5 to 1 percent in sugar water) are the workhorse for Argentine ants; the roughly 5 percent prepackaged stations are weaker on big infestations |
| Fipronil | Slow | Gel and liquid station baits | Effective slow-acting choice; keep away from children and pets |
| Hydramethylnon | Slow | Granular and station baits | Effective; granules must stay dry to be taken |
| Abamectin (avermectin B) | Slow | Station baits | Effective slow-acting choice |
| Indoxacarb, propoxur | Fast | Station baits | Rated less effective by UC IPM because they act too quickly to be shared |
Where to put ant bait (and where not to)
- On the trail, at the entry. Ants find bait by walking into it. Set it where the line comes through the window frame, the outlet, the gap under the sink.
- Outside first when you can. UC IPM prefers outdoor placement near trails and nest openings, spaced 10 to 20 feet around the foundation, at least one per side of the house, in shade so the bait does not cook or dry.
- Not where you sprayed. Residue from a recent spray keeps ants away from the station.
- Not in the sun. Heat evaporates liquid bait, concentrates it, and can make it repellent.
- Out of reach. Children and pets; use enclosed stations indoors.
- Check it. Empty, dried or rancid bait does nothing; refill and replace.
How to keep ants out of the house for good
Bait wins the week; exclusion wins the year. UC IPM is explicit that baits alone usually will not control Argentine ants without exclusion. Caulk cracks around windows, doors, pipes and wires (ants travel along wires and pipes). Keep plants, grass and mulch at least a foot off the foundation, and trim branches that touch the house. Fix leaks and misdirected sprinklers. Store food in sealed containers and take out the garbage often. Submerge an ant-infested potted plant for 20 minutes in a bucket of water with one to two tablespoons of insecticidal soap per quart. Our ant control page covers what the sealing looks like on a service visit.
Ants in the kitchen, the bathroom, after rain and in a heat wave
Kitchen. The classic trail to the counter, the pet bowl or the trash. Food is the draw; bait at the entry and clear the food. If they are tiny and black, read tiny black ants in the kitchen.
Bathroom. Water is the draw. Argentine ants head indoors for moisture when it is hot and dry, and the sink drain, the toilet base and a damp towel are oases. Dry it out, fix the drip, bait the trail.
After rain. Winter storms flood shallow nests and push whole colonies indoors overnight. It passes faster if you bait rather than spray; here is why ants invade after it rains.
Heat wave. Late summer is the other surge, for water and cool. Same play: bait, dry, seal.
When DIY ant control is not enough
Call when the ants are coming from somewhere you cannot bait, when they keep returning after two honest rounds of baiting and sealing, when they are nesting inside a wall or an electrical box, or when you simply do not want to run a three-week program yourself. What we do is the same program at a professional scale: a non-repellent treatment the ants cannot detect, the right bait for the season placed along the actual trails, and the entry points sealed. Argentine ant work is quoted in writing after a look; our one-time general pest visits near Arcadia are priced on the cost page, and photos to (626) 409-1584 get a free read.
Sources
Common Questions
Quick Answers.
How do I get rid of ants permanently?
You do not kill a block-wide Argentine ant supercolony; you make your house the one place on the block it cannot feed. Bait the colony down, seal the entry points, keep food and water out of reach, and bait again at the first scout each spring. Done that way, ants stop being a kitchen problem and become an occasional outdoor one.
What kills ants instantly?
Soap and water, window cleaner or any contact spray kills the ants you can see in seconds, and that is the problem: it only kills foragers, erases the trail that would have led them to your bait, and leaves the queens untouched. Fast is the wrong goal. Slow bait that gets carried home is what ends it.
Do ant baits actually work?
Yes, when the ants accept them and you leave them alone. UC IPM found liquid borate sugar baits can cut Argentine ant numbers noticeably within a week or two. Baits fail when they are the wrong food for the season, placed where ants do not trail, dried out, or sprayed around so the ants never reach them.
How long do ant baits take to work?
Five to ten days to see fewer ants, and several weeks for the colony to collapse, according to UC IPM. The first day or two you will see more ants, because the bait is recruiting them. That is the bait working.
Why are there more ants after I put out bait?
Because foragers lay a trail to good food and recruit nestmates. A crowd at the bait station is exactly what you want; it means the toxicant is heading back to the nest. Leave it, do not spray, and refill when it runs low.
Where should I put ant bait?
On the trail, not near it: at the point the ants enter, along the baseboard route they follow, and outdoors at trail and nest openings along the foundation every 10 to 20 feet, in shade. Keep it out of reach of kids and pets, and do not spray anything near it.
Are ant traps and ant baits the same thing?
What stores sell as ant traps are bait stations: a plastic housing with slow-acting bait inside that ants carry home. Sticky traps and glue boards are not useful for ants. A trap that kills ants on contact is really just a spray in a box.
What is the best ant killer for Argentine ants?
A slow-acting sweet bait the ants will take: liquid borate at low concentration for sugar-feeding Argentine ants, or station baits with fipronil, hydramethylnon or abamectin. UC IPM rates fast-acting baits as less effective because they kill foragers before the bait is shared. We never name brands; we match the active ingredient and the food to what the ants are eating that week.
Why are there ants in my bathroom?
Water. In hot, dry stretches Argentine ants push indoors for moisture and find the sink drain, the base of the toilet, damp towels and a slow leak under the vanity. Dry the area, fix the drip, and bait the trail where it comes in.
Why do I have ants when my house is clean?
Because the colony outside is enormous and your house has water, warmth and shelter even when it has no crumbs. Weather drives most indoor surges: heat and drought in summer, flooding rain in winter. Clean helps; sealing and baiting fix it.
Does vinegar get rid of ants?
It erases the scent trail, which can stop today’s line of ants, and that is all. It does not reach the nest and it does not keep the next trail from forming. Use soapy water for the same effect and spend the effort on bait and caulk.
Do ants go away on their own?
The trail often does, when the weather changes or the food runs out, which is why spraying seems to work. The colony outside does not go anywhere, and the next hot spell or rainstorm brings a new trail. Baiting and sealing are what change the pattern.
What is the best ant trap?
A bait station the ants will actually feed from: a sweet, slow-acting bait for Argentine ants, placed on the trail and left alone. Sticky traps catch nothing useful, and any station that kills on contact is a spray in a box. Judge a station by whether ants are crowding it on day two, not by how many are dead on day one.
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About the Author
Joshua A. Westad is the owner and licensed operator of ExterMetro Termite and Pest Control in Arcadia, CA. He holds California SPCB Company Registration #8828 (Branch 2 & 3), is a licensed WDO inspector, and has worked San Gabriel Valley homes and businesses for over twelve years — hands-on in the field on every kind of job the valley throws at him.
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