When Is Termite Season?
Subterranean termite swarmer events — the most visible sign most homeowners ever see of termite activity — occur in spring, typically between March and June across most of the eastern United States. Swarm events are triggered by warm temperatures (above 70°F), high humidity, and often by rain events followed by sunny afternoons. In the Mid-Atlantic and Northeast, the peak swarmer window is late March through May. In the Deep South and Gulf Coast states, swarms occur earlier, beginning in February or March.
However, termite activity is not seasonal — only the swarmer event is. Subterranean termite colonies are active year-round, feeding continuously in the wood of infested structures and expanding their tunneling networks whenever temperatures allow. A colony does not pause during winter; it simply moves deeper in the soil below the frost line and continues feeding in the wood above. Swarmer season is the most dramatic indicator of termite activity, but it is not the only time termite damage occurs.
What Do Termite Swarmers Look Like?
Termite swarmers (alates) are reproductives that leave the parent colony to establish new colonies. They have four equal-length wings (all approximately the same size), straight antennae, and a broad waist with no pronounced segmentation between the thorax and abdomen. This distinguishes them from flying ants, which have unequal wings, bent antennae, and a narrow pinched waist.
Swarmers themselves cause no structural damage — they neither eat wood nor establish the colony feeding tunnels. The significance of a swarm event is what it indicates about the source colony: a colony large enough and mature enough (typically 3 to 5 years old) to produce reproductive swarmers has already caused substantial structural damage at the source. Finding swarmers inside a home, particularly emerging from baseboards, window frames, or from soil around the foundation, means an established colony is already feeding on the structure.
Swarmers found on exterior windowsills in spring do not necessarily indicate that the source colony is in the structure — the colony may be in adjacent soil, a nearby stump, or landscaping timber. An inspection by a licensed Wood-Destroying Insect (WDI) inspector is the only way to determine whether the source colony has breached the structure.
Key Signs of Active Termite Activity
Beyond swarmers, the signs of active subterranean termite activity in a structure are:
Mud tubes on foundation walls. Subterranean termites construct protective tubes of soil, mud, and termite secretions to travel from the soil to wood while maintaining the high humidity they require to survive. Mud tubes are typically pencil-width to finger-width and run vertically from grade level up foundation walls, piers, and concrete block to the wood framing above. Breaking a mud tube and returning 24 to 48 hours later to see if it has been repaired confirms an active colony.
Hollow or blistered wood. Termites consume wood from the interior, following the grain and leaving a thin exterior shell. Tapping infested wood with a screwdriver produces a hollow sound distinct from solid wood. In more advanced infestations, wood surfaces appear to blister or appear waterlogged. Probing with a screwdriver reveals that the wood can be easily penetrated below the surface layer.
Discarded swarmer wings. After landing, swarmers shed their wings immediately. Finding a pile of equal-length wings near a window, door threshold, or at a foundation crack is a specific sign that a swarm event occurred inside or immediately adjacent to the structure.
Frass. Drywood termites (less common than subterranean termites in the eastern US, but common in the Gulf Coast and California) push fecal pellets out of their galleries through small kick-out holes. Frass appears as small, oval, sand-like pellets with six ridged sides. It accumulates in small piles below the kick-out holes. This is distinct from subterranean termite mud tubes.
The Two Standard Treatment Options: Liquid Barrier vs. Bait System
For subterranean termites, there are two primary treatment approaches used by licensed pest control companies: liquid barrier treatments and underground bait station systems. Both are proven and approved. The right choice depends on the property type, infestation severity, and homeowner preference.
Liquid barrier treatment involves drilling through the concrete slab, foundation wall, or soil adjacent to the foundation and injecting a termiticide into the soil around the entire perimeter of the structure. This creates a continuous chemical zone in the soil that termites cannot pass through without coming into contact with the termiticide. Products currently used include non-repellent termiticides (Termidor, Altriset, Taurus SC) that termites do not detect and carry back to the colony, and repellent termiticides that terminate at the barrier.
Liquid barriers are the preferred approach for active, confirmed infestations where the colony has breached the structure. Treatment is typically completed in a single day. Warranty periods are 5 years for most major termiticides, with annual inspection required to maintain the warranty. Cost for a standard single-family home runs $800 to $2,500, depending on linear footage of the foundation perimeter and soil accessibility.
Bait station systems (Sentricon, Advance Termite Bait System) involve installing in-ground monitoring stations around the structure perimeter. Stations are checked quarterly; when termite activity is detected in a station, the monitoring cartridge is replaced with an active bait cartridge. Termites consume the bait and transfer it to nestmates, eventually suppressing the colony. Bait systems take longer to achieve colony elimination than liquid barriers — typically 3 to 12 months depending on colony size and foraging activity — but do not require drilling into the slab and are considered less disruptive to the structure and landscape.
Bait systems are typically preferred for ongoing prevention after a liquid barrier treatment, for properties where drilling through the slab is not feasible, and for homeowners who prefer a monitoring-based approach. Annual renewal fees run $300 to $600 per year depending on the number of stations.
What Does Termite Treatment Cost in 2026?
Current pricing for the most common residential termite treatment options:
- Professional WDI inspection: $75–$150 for a standalone inspection; many companies apply the inspection fee toward treatment if you proceed.
- Liquid barrier treatment (average single-family home, 2,000 sq ft): $800–$2,500 depending on linear foundation footage and regional pricing.
- Bait station system installation: $1,200–$2,500 for installation, plus $300–$600 per year for annual monitoring and renewal.
- Localized wood treatment (for limited, accessible infestations): $300–$800 for direct wood injection or spot treatment, typically for drywood termites or very early-stage subterranean activity.
- Drywood termite tent fumigation (whole-structure): $1,500–$4,000 for a standard home; required when infestation is distributed throughout multiple areas of the structure and localized treatment is insufficient.
Always get at least three written quotes from licensed pest control companies before proceeding with termite treatment. Verify that each company holds a current state pesticide applicator license and WDI inspector certification in your state. Termite treatment is a significant structural intervention — price is not the only consideration, and the company with the lowest quote may not be providing the same product or treatment depth as higher-priced competitors.
Termite Season Action Plan for 2026
If you find swarmers inside your home between now and June: schedule a professional WDI inspection within 7 to 10 days. Do not wait for additional swarm events as confirmation. The swarm is confirmation enough that an established colony is nearby.
If you have not had a termite inspection in more than 3 years: schedule a preventive WDI inspection. In high-risk areas (eastern seaboard, Gulf Coast, southeastern states), the question is not whether your home will be targeted by termites but when. Annual inspections and an active bait station monitoring program are the standard of care for homes in moderate to high termite pressure areas.
If your current termite protection warranty is expiring: contact your provider for renewal. Most liquid barrier termiticides require annual inspection to maintain the 5-year warranty. Lapsing the warranty means a new full-price treatment will be required if activity is detected rather than a reduced-cost retreatment under warranty.