Pest control in New Hampshire follows the seasons more than in most states. Ticks come out of the leaf litter in April and stay active into November. Carpenter ants swarm out of wet wood in spring. And when the nights turn cold in October, mice look for a warm wall, which in the Lakes Region often means a camp nobody will open until May. An exterminator who works in Wolfeboro or Ossipee spends the fall on mice; one in Derry spends the summer on ants and wasps. Both should hold the same state credential.
Confirming an applicator's state certificate
New Hampshire regulates the person who applies pesticides for pay. RSA 430:33 makes a state registration certificate the price of entry for anyone treating other people's property for pay. Applicants sit an exam, show they are financially responsible for damage, and renew every year. The Division can suspend or revoke it for careless application.
The catch is that you cannot type a name into a state website and see the result; the pesticide division puts out its lists as documents instead. So:
- Ask the company for the certificate number of the person who will treat your house, not just the company's.
- Call or write to the state pesticide office at the Department of Agriculture and ask whether that number is current.
- Ask which products will be used, and keep the label or a product list for your records.
A technician who will not give you a number, or who works under someone else's certificate without supervision, is a reason to call another company.
Ticks from April into November
Ticks are the pest New Hampshire homeowners ask about most, and they are active across the state from April through November. Spraying the edge of the yard is the most common service. Before you sign up:
- Ask what product is used and how often it is applied in a season.
- Ask how the technician keeps spray away from vegetable gardens, play areas, a private well and a neighbor's yard.
- Ask whether the company also recommends habitat work, such as raking out the leaf layer and cutting back brush along the woodline, which cuts tick numbers without chemicals.
If your property is on a lake or river, pesticide rules tighten near the water. Within the 50-foot waterfront buffer, RSA 483-B:9 limits pesticide and herbicide application to licensed professionals or special permits. Ask whether the company sprays shoreland lots and how it handles that strip.
Carpenter ants and the wet wood they follow
Carpenter ants do not eat wood; they tunnel into wood that is already damp or rotting. A spring swarm of large black ants inside the house, or piles of sawdust-like frass under a window, usually means a colony in wet wood nearby: a leaking sill, a rotted deck ledger, a roof leak in a wall.
That makes carpenter ants half a pest problem and half a carpentry problem. A good exterminator in Jaffrey or Rindge will look for the moisture source and tell you to fix it, because treating the colony without fixing the leak invites the next one. Ask whether the inspection includes finding the nest and the wet wood, and whether they will tell you which repairs to make.
Mice in closed camps over the winter
In Tuftonboro, Freedom, Effingham and the other lake towns, mice move into closed camps in October and November and spend the winter in drawers, insulation and furniture. Owners find the damage in spring.
The lasting fix is exclusion: sealing gaps around pipes, vents, foundation sills and doors so mice cannot get in. Ask an exterminator:
- Will you seal entry points, and with what material? Steel wool and caulk, metal flashing or hardware cloth last; foam alone does not.
- What do you use inside: snap traps, bait stations, or both? Bait stations in a closed camp can leave dead mice in the walls.
- Will someone check the camp during the winter, and what does each visit cost?
Get exclusion done in early fall, before the mice arrive, rather than after.
Wasps and yellow jackets by late summer
By August, yellow jacket nests in the ground and paper wasp nests under eaves and deck boards have grown to their largest, and they are most defensive in late summer and early fall. A nest by a door, a play area or a dock is a common urgent call.
Ask whether the company treats the nest the same day, whether they remove it afterward, and what they charge for a nest that is high up or inside a wall. A ground nest in a lawn is often treated at dusk, when the insects are inside. Do not seal a nest's entrance in a wall yourself: blocked insects can chew through to the inside of the house.
Bed bugs in rentals, dorms and ski condos
Bed bugs travel with people and luggage, so they turn up where people turn over: apartments near the colleges in Durham, Hanover, Keene and Plymouth, ski condos in Lincoln and Waterville Valley, and summer rentals on the Seacoast. They are a different job from an ant or mouse treatment.
If you own or manage a rental, ask a company how they confirm bed bugs before treating, whether they treat with heat, with products, or both, how many visits the treatment needs, and whether adjoining units must be inspected too. Ask what the tenant must do to prepare, and get the follow-up inspection in writing. Treating one room or one unit while the neighbor's goes untreated rarely holds.
Wells, children and pets: how products are used
Many New Hampshire homes draw water from a private well. NHDES recommends testing private wells every three to five years (NHDES private wells), and anyone treating around the foundation should know where the wellhead is. Tell the technician where the well is, and ask how far from it they will treat.
If you have young children or pets, ask how long they should stay off treated areas and whether there are lower-toxicity options for your pest. A professional should be able to explain the trade-offs without pressure.
Pricing a general treatment and comparing plans
A one-time general pest treatment runs about $120 to $300 in the New Hampshire pest control cost estimate. Quarterly plans, carpenter ant treatments, rodent exclusion and bed bugs are priced separately and cost more.
When you compare companies, look at what an inspection includes, whether follow-up visits are free if pests return, what a plan costs over a full year and how to cancel. Get the price, the pests covered, the products and the visit schedule in writing. Ask for the applicator's certificate number to be written on the service agreement.
In Lancaster or Jefferson, the nearest company may be a long drive away. Ask whether there is a travel charge and how quickly they can come for an urgent problem such as a wasp nest by a door.
