Argentine ants run most of Southern California. Their colonies aren't single nests — they're sprawling networks with multiple queens, which is why killing the trail you can see accomplishes almost nothing. The colony just routes around it.
Start with water
On almost every heavy Argentine ant job, the real driver is moisture: over-watered planters, irrigation spraying the foundation, a hose bib that drips all night, pet water bowls by the door. Ants establish where water is reliable. Cut the reliability and the pressure drops before any product goes down.
Then feed, don't just spray
Repellent sprays on a trailing colony mostly scatter it — the classic "now they're in three more rooms" outcome. Non-repellent treatments and well-placed bait work with the colony's own food-sharing instead of against it. Workers carry it home; the network does the distribution for you.
- Find the trails back to soil, planters, and tree lines — treat the route, not the room.
- Trim vegetation touching the structure; it's a bridge you can remove in two minutes.
- Seal the obvious entry points around pipes and window frames.
- Tell the customer plainly: results build over days as bait moves through the colony.
The honest timeline
A heavy Argentine ant property is a management program, not a one-visit event. Say that up front, document the moisture conditions in the service note, and each return visit gets easier than the last.