The short version
Most termite problems in Portsmouth are eastern subterranean termites, and the usual fix is a liquid soil treatment or bait stations. Start with an inspection; $75–$250 is typical.
- Look for mud tubes, shed wings and hollow-sounding wood.
- Swarms usually show up from April through June.
- The usual fix is a soil barrier or bait stations.
- An inspection typically costs $75–$250.
- Insurance usually doesn’t cover termite damage.
Anyone in Portsmouth who owns, rents out, or is buying a home and wants to know whether termites are a real concern.
What to look for
Termites work quietly. A colony can feed inside a wall for years. Winter lows around Portsmouth average near 16°F, so termites retreat deeper into the soil, though colonies under heated basements can stay active all winter. Spongy floors or bubbling paint usually mean long-running damage. So it's worth an inspection, even for one or two signs.
- 1Discarded wings caught in spider webs.
- 2Blistered or bubbling paint on wood surfaces.
- 3Termite activity reported at a neighbor's home.
- 4Buckling laminate or warped hardwood flooring.
- 5Damage found during a remodel or repair.
- 6Piles of identical shed wings on windowsills.
Why it’s worth acting soon
- Colonies grow and spread every year they go untreated.
- Damage hides behind drywall, flooring and trim.
- Homeowners insurance usually doesn’t cover termite damage.
- An active infestation can complicate a home sale.
Treatment options and typical costs
Termite Inspection and WDI Report
$75–$250
The inspector checks the foundation, garage, attic and damp spots. Bring up anything you’ve noticed.
- Time
- 60–120 minutes
- Best for
- Every job, real estate closings, and yearly peace of mind
Annual Renewal and Monitoring
$150–$400 per year
Ask what a renewal in Portsmouth actually includes, and whether it covers retreatment or repairs. A retreatment-only plan is common; damage repair coverage costs more.
- Time
- 30–60 minutes per visit
- Best for
- Keeping a treated home protected after the initial job
Liquid Soil Termiticide Barrier
$1,200–$3,500 (often $3–$16 per linear foot)
A liquid barrier treatment around a Portsmouth home means trenching and rodding termiticide into the soil along the foundation. Non-repellent products let termites pass through and carry the chemical home to the colony under Portsmouth.
- Time
- Half a day to a full day
- Best for
- Active subterranean termites; fast knockdown around the foundation
Localized Wood, Foam, and Borate Treatment
$250–$1,500
Spot treatment works when the Portsmouth inspector can see and reach the whole infestation. Small drywood galleries, porch posts, and exposed sills are typical targets.
- Time
- 1–3 hours
- Best for
- Small drywood spots, wall voids, and exposed framing
Prices are typical published ranges. Ask what’s included before you compare quotes.
Drywood termites can fly straight into attic framing through vents, so attics belong on the inspection list in warm climates.Which termites live around Portsmouth.
It needs steady moisture. It nests in soil and builds mud tubes to reach wood. The termite you're most likely to meet in Portsmouth is the eastern subterranean termite.
Local termites conditions in Portsmouth.
A provider who works Portsmouth and New Hampshire every day can point out the specific conditions that matter most here, and getting the scope, price, and follow-up terms in writing makes it easier to compare options. Knowing Portsmouth's seasonal timing lets you schedule treatment before the busy stretch rather than after it, which usually means faster service and a more accurate quote. An inspection in Portsmouth usually starts outside and works inward, checking the foundation, gaps around doors and windows, and any moisture or clutter near the structure first. Around Portsmouth, the area is mostly urban, so termites pressure can differ from one block to the next depending on how tight the entry points are and how much food, water, or shelter is close by. Portsmouth sits in a humid continental climate, and that sets the pace for termite activity here: spring swarm season (March-May), warmer earlier in the south.
Sealing the gap where pipes enter the house takes away one of the easiest routes in. It won't replace treatment, but it helps.When termites swarm here.
Save a few in a bag, or snap a clear photo. A swarm inside usually means it's in the house. A swarm outside means a colony is nearby. Around Portsmouth, eastern subterranean termites usually swarm from April through June, typically on a warm, sunny day after rain. Swarm season is when termites show themselves.
Where to look around your house.
The same advice applies across the area, from Portsmouth out to Dover and Rochester. Wood should stay several inches above the ground. Outside, check porches, steps and decks that touch soil. Look around window wells and unfinished walls. Plenty of homes in Portsmouth have basements, so check where the wood framing sits on top of the foundation wall.
A year of termites in Portsmouth.
- Winter: a good time to book an inspection in Portsmouth, before swarm season starts. - Fall: with about 48 inches of rain a year in Portsmouth, make sure gutters and downspouts carry water well away from the foundation. - Summer: with highs around 80°F in Portsmouth, termites follow moisture, so watch AC drain lines, sprinkler zones and hose bibs. - Spring: swarm season. Around Portsmouth, expect it from April through June. Check windowsills and light fixtures for wings.
What happens at an inspection.
Photos help. Afterward, ask them to show you what they found. A moisture meter and a probe help them find hidden activity. They'll check the basement walls and sill plate. Inside, they check the garage, baseboards, plumbing gaps and the attic. They check the foundation, the soil line and nearby wood. The inspector walks the outside of the house first. Most inspections take an hour or two.
Termites or ants?
- Tunnels: termite galleries are packed with mud. Ant tunnels are clean and smooth. - Debris: termites leave mud. Carpenter ants leave sawdust. - Antennae: termite antennae are straight. Ant antennae bend like an elbow. - Waist: termites are thick through the middle. Ants are pinched. - Wings: termite wings are all the same length. Ant wings aren’t.
Getting ready for treatment day.
Drill holes in slabs or patios get patched afterward. Keep kids and pets inside while the Portsmouth crew applies the product, and ask how long to stay off treated soil. In New Hampshire, eastern subterranean termites swarm in spring, typically on warm days after rain (UGA/Penn State/UKY); northern states run later than the South. Flag sprinkler heads and buried lines. Move boxes away from garage walls. Clear a walking path along the exterior walls. Prep is light for liquid treatments and bait stations.
Mulch and termites.
Wood chips touching the siding trap the moisture termites are after. A dry gap along the house makes mud tubes easier to spot; in Portsmouth that means extending downspouts and pulling mulch back from the slab. Pull mulch back from the foundation and keep the layer thin.
Questions to ask before you sign.
- What do I need to do before and after treatment? - What does the yearly renewal cost? - What does the warranty cover, and for how long? - Is the whole foundation treated, or just one spot? - What product or system will you use? - Which termites did you find, and where?
What affects the price
- Local labor rates and licensing requirements.
- Extent of existing damage needing repair.
- Species: subterranean, drywood, or Formosan.
- Time of year and how booked up local companies are.
- Slab, crawl space, or basement construction.
- Number of bait stations required.
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What's your biggest concern about termites?
When to call for help
Call if you see mud tubes, pellets or an indoor swarm. Hollow-sounding wood is another clue. Buying or selling? Get a wood-destroying insect (WDI) report either way. Lenders often ask for one. It's also the cheapest termite service. Carpenter ants leave clean tunnels and sawdust. Termites leave mud.
What you can do yourself
Treating an active colony is harder. The product has to reach the whole colony. It also needs even coverage around the entire foundation. Store-bought sprays usually kill only the termites you see. Some of the work is yours. Pull mulch back from the foundation. Fix leaks and clear gutters. Keep firewood away from the house.
Termites in Portsmouth
Portsmouth gets about 48 inches of rain a year, and average humidity sits near 70%, so the soil around foundations rarely dries out. New Hampshire is on the low end for termites. Low isn't zero, though. With summer highs around 80°F, Portsmouth's humid continental climate decides when local termites are busiest. A typical home in Portsmouth is worth around $560k, which puts a few hundred dollars for an inspection and prevention in perspective.
Local research
Termites in Portsmouth, NH: what the public record shows
Before you compare quotes, it helps to know which termites actually live in New Hampshire, when they are busiest around Portsmouth, and what the state figures look like. Everything below links to the agency or university page it came from.
Termite species recorded in New Hampshire
- Eastern subterranean termite (Reticulitermes flavipes) — UGA calls it 'the most widely distributed subterranean termite, and it is the most common termite found in the eastern United States'; it swarms February through April in Georgi…
When termites are busiest around Portsmouth
Eastern subterranean termites swarm in spring, typically on warm days after rain (UGA/Penn State/UKY); northern states run later than the South.
Range statement only: UGA describes Reticulitermes flavipes as 'the most common termite found in the eastern United States', and Ohio State calls it the most widely distributed termite species in the continental US. No state-specific figures were verified this session.
Sources: Biology of Subterranean Termites in the Eastern United States (B1209); University of Missouri Extension. Figures are quoted as the source prints them. How we check our sources
Simple ways to keep termites away
- Install a vapor barrier over crawl space soil.
- Keep gutters clean so water does not pool.
- Fix leaking hose bibs, faucets, and pipes promptly.
- Never leave form boards or scrap lumber in the soil.
- Remove tree stumps and buried wood near the house.
A liquid soil treatment goes into a trench along the foundation so termites cross it on their way to the house.Did you know?
Some African termite mounds stand more than 25 feet tall.
Questions people ask
Do I need a termite inspection when buying a house?
Usually, yes. Many lenders ask for a wood-destroying insect (WDI) report. Either way, it's cheap peace of mind. Ask your agent when it's due.
Will termites come back after treatment?
They can. Treatments wear down and new colonies move in. That's what yearly inspections and renewal plans are for.
Can termites damage a house on a concrete slab?
Yes. They come up through expansion joints, plumbing gaps and small cracks. Inspectors check those spots first.
What does a WDI report include?
It lists any termites or damage found. It also notes conditions that invite them, like wood touching soil. It only covers areas the inspector could reach.
Is termite treatment safe for kids and pets?
Used according to the label, yes. Soil treatments stay in the ground. Bait stations are locked and buried. Ask for the label and follow any re-entry times.
Can I treat termites myself instead of hiring a professional?
Around Portsmouth, termites are best caught early through inspection, because the damage is hidden inside wood until it is far along. Around Portsmouth, 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.
Are termites common in New Hampshire?
Low isn't zero, though. Around Portsmouth, the usual culprit is the eastern subterranean termite.
Sources (10)
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