New Hampshire plumbing splits into two worlds. In Manchester, Nashua, Concord and the Seacoast cities, most houses draw on a municipal main and drain to a city sewer. Step off those systems, which happens within a few miles of every downtown, and the house has a drilled well, a pressure tank and a septic tank in the yard. A plumber in Hollis, Gilford or Jaffrey spends a fair share of the week on wells, pumps and treatment gear that a city plumber rarely touches. Knowing which world your house sits in shapes who you call.
Looking up the plumber and the company on the OPLC site
Plumbing is one of the few trades New Hampshire licenses. Under RSA 153:29 the Mechanical Licensing Board issues master, journeyman and apprentice plumber licenses, and an apprentice works under a licensed plumber rather than alone.
There is a second layer people miss. A business that does plumbing or gas work needs a Mechanical Business Entity license of its own, and to get it the company has to show proof of liability insurance (RSA 153:29-a). So when a van pulls into your driveway in Londonderry or Dover, two names should check out: the person doing the work and the company on the invoice.
Both are searchable on the state's license verification page. Type in the license number from the quote, or search by last name, and look at three things: the license type, the expiration date and whether the status is active. A master's license held by the owner does not cover an unlicensed helper working alone at your house.
When can you do your own plumbing in New Hampshire?
More often than in many states. RSA 153:36 exempts a property owner, or the owner's agent, who installs, repairs or replaces plumbing in their own single-family detached house or townhouse, new construction included. Minor repairs on the owner's property are exempt too.
The exemption is narrow in two ways. It covers your own single-family home or townhouse, not a two-family you rent out in Manchester's West Side or a condo building. And it lifts the license requirement, not the code: the work still has to meet the plumbing code and any permit and inspection your town requires. If your town's building office wants a permit for a new bathroom's drain lines, the exemption does not change that.
Gas is handled separately. The same section lets the owner of a single-family stand-alone house do fuel gas fitting in it, but only if it is their primary residence, and the work still has to meet code. Many owners who are comfortable sweating copper still hire a licensed gas fitter for a range or dryer line.
Arsenic and radon in the well: what the plumber can and can't fix
NHDES estimates that about one private well in five in the state has arsenic above the drinking-water standard, and that a majority exceed its advisory level for radon in water. No law makes a homeowner test a private well. The NHDES private wells page recommends testing every three to five years, and before buying a house with a well.
That matters for hiring, because the plumber should be working from a lab result, not a guess. Get the test first, then ask for quotes on a treatment system sized to it. Reasonable questions:
- Which contaminant is the system meant to remove, and to what level?
- Is it a whole-house system or a single tap under the kitchen sink?
- What maintenance does it need, and what do replacement filters or media cost each year?
- Will you retest after installation to show it works?
Arsenic and radon need different equipment, and a system bought for hardness or iron may do nothing for either. A plumber in Amherst or Weare who installs treatment gear regularly should be able to explain the difference without notes.
The sewer connection and the drainlayer license in six cities
Inside the sewer districts, the pipe from your foundation to the street is its own job. No New Hampshire city licenses general contractors, but a handful license the people who dig and connect building sewers. Nashua, Hudson, Manchester, Derry, Dover and Portsmouth run drainlayer licenses, and Nashua publishes its roster as a drainlayer list.
If a camera inspection in Hudson or Dover shows a cracked clay lateral or roots in the line, ask the plumber whether they hold the city's drainlayer license or will bring in someone who does. A plumber who stops at the foundation wall is not doing anything wrong; the excavation in the street simply falls under a different set of rules.
Outside those districts, the line runs to a septic tank instead, and the septic system has its own permits from NHDES. A plumber can clear a slow house drain, but a failed leach field is a job for a septic designer and installer.
Heat pump water heaters and the $900 rebate
Water heaters are a frequent plumbing call, and in 2026 NHSaves pays a $900 rebate per unit on a qualifying ENERGY STAR heat pump water heater up to 85 gallons, with the rebate applied at the counter through participating distributors for tanks of 55 gallons or less (NHSaves heat pump water heaters).
A heat pump water heater pulls heat from the air around it, so placement matters. It cools and dries the room it sits in, which can be welcome in a damp Seacoast basement and less welcome in a small closet. It also needs a drain for condensate. Ask the plumber where the unit will go, whether it needs a new electrical circuit (that part is an electrician's work) and who will file the rebate.
Opening and closing a lake camp without a burst pipe
Seasonal camps on Winnipesaukee, Squam and the Ossipee lakes are a big part of a Lakes Region plumber's year. A camp that is closed in October without being drained properly can split a fitting in the first hard freeze, and the leak is often not found until someone opens the place in May. If you own one in Meredith, Alton or Tuftonboro, a few questions help when you book:
- Will the plumber drain the supply lines, the water heater and the pressure tank, and blow out lines that do not drain by gravity?
- Is antifreeze put in the traps and toilets, and is it the nontoxic kind meant for plumbing?
- Who shuts off and restarts the well pump, and is the pump on a heated circuit?
- Will someone check the place after the first deep cold snap?
Book the opening early as well. Plumbers in the lake towns fill their spring schedules fast, and a camp that has to be ready for a Memorial Day rental needs its date set well before April.
Pricing a service call from Nashua to Lancaster
A small New Hampshire plumbing job runs about $240 to $580 in the New Hampshire plumbing cost estimate, whose default is a faucet replacement. Toilets, sinks, drain clearing and leak repairs have their own settings there. A water heater swap, a treatment system or a sewer lateral runs well past that range.
Distance is the other variable. In the southern tier a plumber may be ten minutes away. In Coös County, where a company in Lancaster or Berlin might cover a whole county, travel time can be a real line on the bill. Ask whether the company charges a trip fee, a minimum hour, or portal-to-portal time, and whether emergency rates start at a fixed hour.
New Hampshire has no home-improvement statute setting contract terms, so the written quote is what you hold the plumber to. Get the scope, parts, price and warranty in writing before work starts. If a company misrepresents its work or its license, the state's Consumer Protection Act bars unfair and deceptive business practices (RSA 358-A:2), but a clear quote heads off most disputes before they need a statute.
