101 Exterminators
Service Areas
Pests
Articles
Guides
Resources
A modern craftsman home in a leafy Silicon Valley suburb — Redwood City, California service area

Ant Elimination

Ant Control in Redwood City, CA

101 Exterminators does ant control in Redwood City with baits rather than contact sprays, because the ant you almost certainly have is Linepithema humile — the Argentine ant. We are California licensed, SPCB Lic. #9119, and have worked San Mateo County. Spraying a trail kills the workers you can see and leaves the colony that sent them. Bait moves through the whole population instead.

(831) 500-161310% off your first service with a recurring plan

Schedule Service

Local Context

One Argentine Ant Population Runs From Woodside Plaza to the Bay

Argentine ants on the Peninsula do not behave like textbook ant colonies. Instead of separate nests that fight each other, they operate as one interconnected population with many queens, sharing workers across property lines. That is the whole reason a treated yard in Woodside Plaza or Redwood Oaks refills within a week or two — the ants are not rebuilding, they are walking back in from three doors down.

Redwood City's water pattern sets the timing. Nearly all the rain lands between November and April, so the first storms flood shallow nests along Redwood Creek and Cordilleras Creek and in the irrigated planting strips through Roosevelt and Palm Park, and the colony moves indoors within a day or two. The reverse happens in the dry half of the year. By late summer the soil is hard and the same ants follow moisture to dishwasher pans, sink traps and bathroom slab edges.

Nothing in the calendar stops them. January lows here average near 41°F, cool enough to slow foraging and never cold enough to end a season. Carpenter ants are a separate and less common finding, usually in framing already softened by a leak or by sub-area moisture in the older houses west of El Camino Real, and they need the moisture source corrected rather than just the ants treated.

How We Work in Redwood City

We identify the species first, because Argentine ants and carpenter ants get opposite treatments. For Argentine ants we place slow-acting gel bait on the active trails indoors and treat the exterior perimeter — foundation line, hose bibs, irrigation boxes, utility penetrations, fence lines — so the returning population meets something on the way in. We ask you not to wipe the trails before we arrive, since the trail is the map. On heavily irrigated Redwood City lots we also look at where landscaping meets the stucco.

Redwood City Climate

Redwood City is warmer inland than the Peninsula coast, with seasonal winter rain. Weather alone does not establish termite activity.

Housing Stock

Older houses around Mount Carmel and newer homes toward Redwood Shores can have different foundations and access. The construction and later alterations determine which wood is visible.

Why Local Expertise Matters

In Redwood City, a raised floor may expose underfloor wood; a slab or finished addition may not. Ask for the inspected areas, any limits, and the written basis for a treatment recommendation. A separate Section I/Section II report is available on request; the report itself does not decide a transaction’s repair terms.

Home maintenance

How do you stop Argentine ants coming into a Redwood City home?

Seal their entry points and take away water. Redwood City’s summers are long, hot and rainless, with July averaging no rain at all, and Argentine ants come indoors looking for water as much as food. Winter storms send them in again when their shallow nests flood.

Trimmed hedge with a clear gap of bare mulch between it and the siding and foundation vent

  1. Fix every indoor drip

    Ants find leaking faucets, damp sink cabinets and dishwasher lines in the dry months. Repair leaks and keep cabinets under sinks dry from June through September.

  2. Seal the trail’s entry point

    Follow a trail back to where it enters, often a window frame, outlet, baseboard or the gap around a pipe, and caulk it.

  3. Keep foliage off the walls

    Shrubs, vines and tree limbs touching the house let ants walk in over the foundation. Trim a clear gap around the walls.

  4. Hose aphids off nearby plants

    Argentine ants tend aphids and scale for honeydew. Knocking aphids off roses, citrus and hedges next to the house removes a food source that keeps colonies close.

  5. Seal sweets and pet food

    Store sugar, honey, syrup and dry pet food in containers with tight lids, and wipe counters before bed. In a hot Redwood City August, a single uncovered pet bowl can pull a trail across the kitchen overnight.

When to do it

Water checks from June through September, and sealing in October before the winter storms.

Maintenance guidance: UC IPM, Ants (Pest Notes 7411)

Warning Signs

When to Ask About Ant Control in Redwood City

Species identification, followed by bait placement for slow-acting colony elimination. For carpenter ants — which nest in moisture-damaged wood — we identify and treat the nest location directly. For fire ant mounds, we use targeted mound treatments plus a broadcast perimeter application. Exterior perimeter liquid treatments are applied to prevent re-entry, with interior gel bait placed in active foraging areas.

Foraging trails along baseboards, windowsills, counters, or appliances — especially in kitchen

Live ants in kitchen cabinets, under the sink, near pet food, or around any sugar/food source

Sawdust-like frass near wood — indicates carpenter ant activity inside wood

Visible mounds in lawn or soil beds — fire ant indicator

Large (6–12mm) black ants with bent antennae in bathrooms or attic — carpenter ants

Repeated ant activity despite over-the-counter spray treatments — indicates spray-avoidance in colonies

How It Works

What to Expect from Ant Control in Redwood City

Tell us where the ants enter, where the trail leads and how often it returns. The location of activity helps us decide what to inspect.

01

Species Identification

Misidentifying ant species leads to failed treatments. We identify the species present — Argentine, carpenter, fire, pavement, odorous house — before selecting treatment methodology.

02

Nesting Site Assessment

Carpenter ants nest in wood. Argentine ant colonies can extend across an entire block. Fire ants create visible mounds. Each species nests differently and requires us to find the colony before treating.

03

Targeted Bait & Barrier Treatment

Slow-acting gel baits are placed in foraging trails — workers carry the bait back to the queen, eliminating the colony from within. Exterior perimeter liquid is applied to prevent new entry.

04

Follow-Up & Assessment

We return to confirm colony suppression, replenish bait if needed, and treat any secondary colonies that become active as the primary colony is eliminated.

Why 101 Exterminators

Why Choose 101 Exterminators for Ant Control in Redwood City

Species-Specific Treatment

Argentine ants, carpenter ants, and fire ants each require a different product and approach. Generic "ant spray" does not work equally for all species.

Bait-Based Colony Elimination

Slow-acting bait reaches the queen through worker activity. This is the only way to achieve lasting colony elimination without returning every few weeks.

Exterior Barrier Prevents Re-Entry

A liquid residual barrier on the perimeter prevents new foragers from adjacent colonies from entering — critical in Argentine ant supercolony territory.

Interior-Safe Methods

Gel bait placement in cracks and crevices does not require broadcast interior spraying. Food and dishware do not need to be removed for interior bait treatments.

Common Questions

Ant Control FAQs for Redwood City

Why do the ants come back a week after treatment in our Redwood City yard?

Because Argentine ants on the Peninsula function as one large interconnected population, so a treated lot repopulates from neighboring yards rather than from a surviving nest of its own. Killing foragers on contact does not touch that. Slow-acting bait works better because workers carry it back and share it before it takes effect, and an exterior perimeter treatment keeps the returning ants outside while it does.

Should I spray the ant trail on my kitchen counter before you come out?

No — leave the trail if you can stand it, and clean only the food surfaces. The trail shows us where they are entering and which direction the colony sits, and that changes where the bait goes. A store-bought spray also scatters workers and can push a colony to split into new sites. Wipe the counter itself and leave the wall or baseboard line alone.

Are the tiny black ants in Redwood City kitchens the same ones in the garden?

Almost always yes — Argentine ants, about an eighth of an inch, dull brown to black, moving in steady single-file lines. They nest outdoors in soil, mulch, planter strips and under pavers, then send foragers inside for water and sugar. That is why treatment that ends at the kitchen wall does not hold. The nest is in the yard or the neighbor's yard, and that is where the work has to reach.

Local Pest Pressure

Common Pests We Treat in Redwood City

Every area has its own pest profile shaped by climate, housing, and geography. These are the pests we see and treat most often in Redwood City — tap any one to learn how to identify it and what treatment involves.

Argentine Ants

Identify trails and entry points before choosing treatment.

Drywood Termites

Pellets or damaged wood can prompt inspection; they do not establish current activity or full extent alone.

Subterranean Termites

Mud tubes or soil-to-wood paths call for identification at the property.

Norway Rats

Bair Island marsh, Westpoint Slough and the port district hold permanent rat habitat directly against residential blocks

Roof Rats

Check roof openings and nearby cover when rodent signs appear.

Ant Control · Redwood City

Schedule Service in Redwood City

Tell us what you have found and where. If you're new to us, start a recurring plan and we'll take 10% off your first service.

Schedule Service(831) 500-1613
Trusted by Redwood City families