The short version
New Hampshire termite problems come from the eastern subterranean termite, a soil-dwelling species that University of Georgia calls the most common termite in the eastern United States. Colonies reach New Hampshire houses through buried wood, deck posts, landscape timbers and mulch piled against the foundation. Swarms happen in spring after the ground warms. Treatment is a liquid soil barrier or a monitored bait system.
- Subterranean termites are the most common species in NH, swarming in spring.
- Damage is not covered by most homeowners insurance.
- Liquid soil treatments and bait stations are the primary control methods.
- Ask any licensed pro what an inspection costs and what their warranty covers.
- Prevention includes reducing wood-to-soil contact and fixing leaks.
This content covers identification, treatment, and prevention tailored to NH’s climate and building styles. Landlords should prevent damage to rental properties. Property managers must protect multi-unit buildings. Real estate agents need termite inspection knowledge for transactions. If you own a home with a basement, crawlspace, or slab foundation, you are at risk. For New Hampshire homeowners, real estate agents, property managers, and landlords.
What to look for
A summer high near 82F with about 44 inches of precipitation and 68 percent humidity gives them a productive warm season with damp workable soil. The connection between yard and structure is where New Hampshire homes get into trouble. Suburban landscaping puts a lot of cellulose in direct contact with soil, and each of those items can host a satellite feeding site. From a rotting timber four feet off the foundation, it is a short underground trip to the sill. The practical implication is that treatment and yard cleanup are the same project, not two separate ones. Reticulitermes flavipes is the species at work in New Hampshire. Ohio State calls it the most widely distributed termite in the continental US, and its range reaches well into northern New England, thinning as winters get colder. What lets it establish here is a house that supplies what the climate does not. A median winter low near 15F pushes the frost line deep, so colonies overwinter well below the surface.
- 1Mud tubes on foundation walls, floor joists, or sill plates—pencil-sized tunnels termites build for shelter.
- 2Swarmers (winged termites) indoors or near windows in spring; often mistaken for flying ants.
- 3Discarded wings near windowsills, doors, or vents after swarming.
- 4Wood that sounds hollow when tapped, or blistered/darkened paint on wood surfaces.
- 5Small holes in drywall or wood, often with frass (termite droppings) nearby.
- 6Buckling floors or sagging ceilings due to hidden wood damage.
- 7Tight-fitting doors or windows that become hard to open from warped frames.
Why it’s worth acting soon
- Structural damage: termites eat wood from the inside out, weakening beams and supports.
- Cost escalation: a small infestation can become a $3,000+ treatment and thousands in repairs.
- Hidden damage: by the time you see signs, termites may have been active for years.
- Sale complications: a termite inspection finding active infestation can kill a real estate deal.
- No insurance coverage: all repair costs come out of pocket.
costs U.S. homeowners billions of dollars a yearTermite damageUSDA Treatment options and typical costs
Liquid Soil Treatment
$1,200–$2,500
A trench is dug around the foundation and a termiticide is applied to create a chemical barrier. Termites crossing the barrier die or are repelled.
- Time
- Lasts 5–10 years depending on product and soil conditions.
- Best for
- Active infestations and preventative protection for slab or basement foundations.
Bait Station System
$1,500–$3,000 initial, plus annual monitoring fees ($200–$400)
In-ground stations are placed around the property containing bait that termites carry back to the colony. Eliminates the colony over time.
- Time
- Ongoing; stations are monitored and replenished as needed.
- Best for
- Long-term control and properties with high termite pressure.
Wood Treatment / Borate Spray
$500–$1,500
Borate-based products are applied to exposed wood surfaces during construction or renovation. Not effective on painted or covered wood.
- Time
- Permanent if not exposed to moisture.
- Best for
- New construction or during remodeling when wood is accessible.
Fumigation (Tenting)
$2,000–$8,000
The entire structure is sealed and filled with gas to kill all termites. Rarely used for subterranean termites; more common for drywood termites (not typical in NH).
- Time
- One-time; no residual protection.
- Best for
- Severe drywood infestations; not usually recommended for NH.
Prices are typical published ranges. Ask what’s included before you compare quotes.
Sealing the gap where pipes enter the house takes away one of the easiest routes in. It won't replace treatment, but it helps.How a colony travels from the woods to your foundation.
The durable version of the fix removes the feeding sites and blocks the route at the same time. A liquid barrier blocks the route, but the colony living in a stump ten feet away is still there, still growing, and still probing for a way past the treated soil. This is why treatment alone sometimes disappoints. From a timber four feet off the foundation, reaching the sill is a short tunnel and a shelter tube up the wall. Each of those becomes a feeding site, and each one puts the colony closer to the house. Stumps left from clearing, root systems decaying underground, buried form boards from the original construction, landscape timbers holding a bed, rotting fence posts and a woodpile that has been sitting since the last cold snap. On a typical wooded New Hampshire lot, that supply is everywhere. It forages outward through soil looking for cellulose, and it settles wherever it finds a reliable supply. A subterranean colony does not target houses.
termites activity by season.
Scheduling before the busy stretch, rather than after it, tends to mean faster service and a more accurate quote, and a local provider can point out the conditions that matter most in New Hampshire. In New Hampshire, checking the foundation, gaps around doors and windows, and any moisture or clutter near the structure usually turns up the conditions that are letting them in. The most useful first step in New Hampshire is to note where you have seen termites and when they appear, because that timeline is what lets a provider focus on the right area instead of treating the whole property.
Crawl spaces are where termites usually get in. Joists, piers and the sill plate should all get a close look.Decks, porches and the wood you forgot is touching dirt.
If you are already replacing a deck, this is the cheapest moment in the deck's life to get it right, and it also solves the rot problem that would have arrived anyway. Move the planter. Cut skirting so it stops above grade. Put stringers on a pad. Set posts on concrete piers with metal standoff bases so end grain stays out of the dirt. The fixes are ordinary carpentry. It gives a colony a protected route from soil to structure, and it keeps that wood damp enough to soften, which makes it more attractive. Each contact point does two things. So are stair stringers resting on a dirt landing, lattice skirting buried a couple inches, planter boxes built against the siding, and trellises stapled to the wall with their feet in a bed. Deck posts set into the ground rather than on piers are the classic case. Then you walk the yard. Ask a New Hampshire homeowner where the wood on their property touches soil and most will say nowhere.
The New Hampshire swarm calendar and what to do that week.
The habit worth forming: inspect at thaw, treat before frost. If you found evidence in September, book it rather than letting the calendar decide for you. October into early November is the last comfortable window for trenching. Soil is workable, basements are dry enough to inspect properly, and treatment gets the full benefit of a warm season. July through September is the productive stretch for both colonies and contractors. Warm still days after rain are the trigger, and coastal areas warm before inland towns. Late May and June is the realistic swarm window in this state, several weeks behind southern New England. Shelter tubes get rebuilt, which makes this the highest-value moment for a walk around the foundation with a flashlight. April and May bring the thaw and the return of surface activity. Soil freezes, foraging retreats, and any colony present is feeding below frost depth or inside a heated basement. Nothing happens above ground from December through March.
When a termite finding counts as an emergency.
What creates urgency is not the insect, it is the load the damaged member is carrying. The honest middle ground is that termites work slowly. Those need an inspection and a plan within days or weeks, not the same evening. What is not an emergency: a spring swarm, a mud tube found on a foundation wall, or damage in a section of trim. That is a call to a structural contractor as well as a pest company. A main girder, a bearing post in the basement or a sill under a load point showing significant damage is the same category. If a probe goes into a ledger or a stringer feels soft underfoot, stop using the structure and get it looked at right away. A deck ledger or stair stringer that has lost structural integrity is a genuine safety issue, and people fall through these. There are exceptions. Most termite discoveries are urgent in the sense of scheduling, not in the sense of tonight.
After the treatment: what you should keep and check.
A barrier plus a stump in the side yard is half a solution. do the yard work you were told to do. Tell the pest company before you trench for a sprinkler line, a fence, a patio footing or a utility, because digging through treated soil creates a gap exactly where someone dug. Then keep the treated zone intact. On a bait system, get the service schedule on paper along with what it costs after the first year, because bait protection continues only while stations are serviced. On a liquid application, a look every year or two is reasonable in this climate. Ask about reinspection. That file matters at resale and it matters if activity returns and you need to discuss retreatment. You want the product name, the date, the areas treated, linear feet trenched, drill locations, and a diagram. Get documentation. The job is not finished when the truck leaves, and the follow-through is mostly paperwork and habits.
What affects the price
- Size of the home and severity of infestation.
- Type of treatment (liquid vs. bait system).
- Accessibility of the foundation (crawlspace, slab, basement).
- Number of bait stations needed (typically 10–20 per home).
- Local labor rates and travel distance in rural NH.
- Warranty options: transferable warranties cost more but add value.
- Pre-treatment repairs (e.g., removing wood debris or fixing moisture issues).
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What is your biggest concern about termites?
When to call for help
Call when you have tubes on masonry, a matched pile of shed wings indoors, or wood that gives way under a screwdriver. Bring a photo and a few insects if you can, because identification decides everything that follows. The second trigger is structural. A deck ledger, stair stringer or porch post that has lost strength is a safety problem before it is a pest problem, and it should be looked at promptly rather than added to a spring list. The third is a transaction: New Hampshire buyers commonly arrange a wood destroying insect inspection, and ordering it early leaves room to treat and document rather than negotiate under a deadline.
What you can do yourself
Inside, keep the basement perimeter clear so the walls can actually be seen, and dry out any chronically damp corner. The treatment is professional work. A soil barrier only functions if it is continuous down to the footing, which means trenching and drilling that no homeowner product can replicate. Do the yard, hire the barrier. The outdoor half of this belongs to you, and on a New Hampshire lot it is the half that lasts. Pull landscape timbers that are rotting into the soil, grind or remove stumps close to the house, get firewood off the ground and away from the wall, and cut mulch beds back so bare foundation is visible below the siding. Where a deck post sits in dirt, replace it with a post set on a concrete pier and a standoff base.
Where you live matters
Our largest New Hampshire city data covers Manchester, Nashua, Concord, Derry and Dover, a mix of older downtown housing and suburban development on wooded lots. Those wooded lots are the local wrinkle: cleared land leaves stumps, root systems and buried construction debris behind, and each one is a food source sitting near a new foundation. With a median home value near $407,500 across our New Hampshire cities, the case for a yearly inspection is straightforward arithmetic against a structural repair nobody insures. New Hampshire spans continental and coastal zones, with a median summer high near 82F, a winter low around 15F, humidity about 68 percent and roughly 44 inches of precipitation a year across our city data. Wet soil and a long enough warm season give a soil colony a real working window even with a hard winter on either end.
Simple ways to keep termites away
- Replace landscape timbers touching soil with stone or composite edging.
- Remove or grind stumps within a few yards of the foundation.
- Set new deck and porch posts on concrete piers with metal standoff bases.
- Keep mulch beds several inches below the bottom of siding and trim.
- Store firewood off the ground and away from the house, not stacked against it.
- Extend downspouts and fix the gutter that ices up and floods one corner each spring.
- Keep a clear, visible strip along basement walls so tubes would be noticed early.
- Have the perimeter inspected annually if the property has had activity before.
A damp cabinet under a leaky sink is worth reporting to your landlord early. Fixing the leak removes what draws termites in.Did you know?
A termite colony can last for decades and hold millions of termites, almost all of them the offspring of one queen.
Termites can't digest wood on their own. Microbes in their gut turn the cellulose into food.
Subterranean termites build mud tubes to cross concrete or brick without drying out.
Questions people ask
How do I know if I have termites or ants?
Termite swarmers have four equal-sized wings that fall off after swarming, while ant swarmers have front wings longer than back wings. Termites have straight antennae and a thick waist; ants have elbowed antennae and a pinched waist. If you find discarded wings that are all the same size, it’s likely termites.
Can I treat termites myself?
DIY treatments rarely eliminate the entire colony. Over-the-counter sprays kill only visible termites, and bait stations need proper monitoring. Professionals use termiticides that are transferred through the colony and have the training to find the source. For active infestations, professional help is strongly recommended.
Does homeowners insurance cover termite damage?
No. Most standard homeowners insurance policies exclude termite damage because it is considered preventable through maintenance. You will have to pay for treatment and repairs out of pocket.
How long does termite treatment take?
A liquid treatment typically takes a few hours to apply, but the termiticide needs time to set. Bait stations are installed in a day, but colony elimination can take weeks to months. Fumigation takes 24–72 hours. Your technician will give you a specific timeline.
What is the best time of year for termite treatment?
Spring is ideal because termites are most active, but treatment can be done any time the ground is not frozen. Winter treatments are possible with specialized equipment. The key is to treat as soon as an infestation is detected.
Do I need a termite inspection to sell my house in NH?
It is not legally required, but most buyers and lenders request one. A WDI inspection can prevent last-minute surprises. If active termites are found, treatment is usually required before closing. Many agents recommend a pre-listing inspection.
How often does a termite treatment need a callback?
In New Hampshire, termites are best caught early through inspection, because the damage is hidden inside wood until it is far along. In New Hampshire, a professional inspection looks for mud tubes, damaged wood, and swarming activity, and treatment targets the soil and the colony rather than just the visible wood.
Sources (16)
The facts in this article come from the public sources listed above. Every home is different, so ask the company you talk to about pricing and what’s included. Published by Termite Exterminator · Updated September 11, 2026 · How we write these guides