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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 since 2005. Spraying a trail kills the workers you can see and leaves the colony that sent them. Bait moves through the whole population instead.

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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

The "Climate Best By Government Test" arch downtown comes from a slogan contest a local resident won in 1925, and the survey behind it was real: a pre-World War I climatological comparison placed Redwood City alongside the Canary Islands and the North African coast. What matters for pest work is what that warmth does. The hills to the west block most of the marine layer that keeps Daly City and Pacifica cool, so summer afternoons here run hot, and the record high of 110°F was set as recently as September 6, 2022. Rainfall averages about 20.5 inches a year, nearly all of it between November and March. Drywood swarmers fly August through October, at the hottest end of the local calendar; subterranean swarms arrive with the rains, February through May.

Housing Stock

North and west of downtown, the Mount Carmel, Edgewood and Centennial blocks have pre-1940 houses on raised foundations, with the original redwood and fir framing still in the walls and attics and crawl spaces a technician can work in. Post-war tract housing spreads south and east from there. Farm Hills and Woodside Plaza went up mostly between the 1950s and the 1970s on the hillside side of town. Redwood Shores is the outlier: a 1960s planned community built on bay mud and former salt-evaporation ponds, with lagoons threaded through it and groundwater close to the slab. Termite species, foundation type and inspection access all change between those four.

Why Local Expertise Matters

Two Redwood City addresses can need opposite work. A 1926 house near Mount Carmel usually means drywood termites in old framing, reached through a crawl space and an attic. A Redwood Shores townhouse on filled ground usually means subterranean activity at the slab edge, plus moisture conditions that land as Section 2 findings on the report. Knowing which conversation you are in before the inspection starts is most of the job. We have been licensed and insured in California since 2005 and hold SPCB License #9119.

Warning Signs

Signs You Need Ants Service 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

Our Ants Process in Redwood City

Every job follows the same methodical approach — no shortcuts, no guesswork. Here is what to expect when you work with us in Redwood City.

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

Ants You Can Count On 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

Citywide pressure with a winter storm peak and a second one at the end of the dry season

Drywood Termites

Pre-1940 framing in the Mount Carmel, Edgewood and Centennial blocks, plus hot inland afternoons through the August-to-October swarm window

Subterranean Termites

Redwood Shores sits about seven feet above sea level on filled salt ponds, putting groundwater within reach of slabs and utility penetrations

Norway Rats

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

Roof Rats

Mature canopy in the older neighborhoods and the creek corridors give roof rats a continuous route to rooflines

Ant Control · Redwood City

Free Pest Evaluation in Redwood City

CA licensed and insured. Written estimate before any work begins. Urgent situations in Redwood City are prioritized.

Schedule an Inspection(831) 500-1613
Trusted by Redwood City families since 2005