One ADU by right
RSA 674:72 requires every district that allows single-family homes to allow one ADU, attached or detached. Towns may not cap the size below 750 sq ft; 950 sq ft is allowed unless the town permits more.
Southern Maine · NH Lakes · NH SeacoastBackyard homes,
Backyard homes,
site work included.
10 turn-key ADU models, $147,000 to $388,000, published before you call. The site work is in the price: clearing, foundation, septic and utilities are in the number before you sign, not added once the digging starts.
- Site work and septic in the price
- Prices published up front
- One contract, all trades
- Owner-operated since
- 2018Owner-operated since
- Excavation & septic in the price
- IncludedExcavation & septic in the price
- Contract covering every trade
- OneContract covering every trade
- Southern Maine, Lakes, Seacoast
- ME + NHSouthern Maine, Lakes, Seacoast
What the price covers
One number, start to keys.
Every published price is a turn-key number on a standard lot. Not a shell, not a kit, and not the building alone. Here is exactly what sits inside it.
What it cannot know is your lot. Ledge, a long utility run, a difficult septic design or a town tap fee will move it, and we tell you which before you sign.
Site prep & excavation
Clearing, cut and fill, grading and drainage.
Foundation
An insulated monolithic slab as standard, engineered for the lot.
Septic hookup
Design through installation, inside the figure.
Utilities
Water, power and the run back to the main house.
The building, finished
Shell through interior finish on a single contract.
Plumbing & electrical
Licensed trades, scheduled as part of the build, so you are not chasing them.
Not included: the land, town tap and impact fees, and anything the lot forces that a standard site does not.
Why us
The site work is where most ADU budgets move.
A backyard home is only partly a building. The rest is excavation, ledge, drainage, a septic system that will pass, and the utility runs back to the main house. That is the half of the job where a quote usually changes after the contract is signed.
Here that work is part of the build. The excavation, the septic design and the installation sit inside the same contract and the same number, so the figure you are given is the figure the job is priced at. If the lot is going to move it, you will hear that early rather than halfway through.
01
Site work
Clearing, excavation, ledge, grading and drainage, scheduled by us rather than fitted around another company’s calendar.
More02Septic
Design through installation. Septic is the most common reason an ADU quote changes after signing, so we price it with everything else.
More03Foundation & utilities
Slab or full foundation, water, power and the run back to the main house.
More04The building
Shell to finish under the same prime contract, with the licensed plumbing and electrical trades managed by us rather than by you.
MoreADU models
Compare all 10 models & pricesPick a plan. See a number.
Every model below is a finished, turn-key price on a standard lot: the plan, the size, and what it costs, together.
The Bean
$147,000starting
- sq ft
- 384
- bed
- 1
- bath
- 1
384 sq ft, 1 bed / 1 bath, 16×24, one story.
View this modelThe Newfield
$196,000starting
- sq ft
- 600
- bed
- 1
- bath
- 1
600 sq ft, 1 bed / 1 bath, 30×20, one story.
View this modelThe Summit
$235,000starting
- sq ft
- 654
- bed
- 1
- bath
- 1
654 sq ft, 1 bed / 1 bath, 30×22, one story.
View this modelThe Shapleigh
$252,000starting
- sq ft
- 800
- bed
- 2
- bath
- 1
800 sq ft, 2 bed / 1 bath, 40×20, one story.
View this modelThe Bentley
$278,000starting
- sq ft
- 750
- bed
- 1
- bath
- 1
750 sq ft, 1 bed / 1 bath with an attached garage.
View this modelThe Spruce
$290,000starting
- sq ft
- 882
- bed
- 2
- bath
- 2
882 sq ft, 2 bed / 2 bath, 42×21, two story.
View this modelThe law changed
ADUs are by right in both states now.
Maine and New Hampshire both rewrote their ADU rules. For most homeowners the question is no longer whether the town allows one. It is what the lot will carry.
Read the rulesGarage conversions
A 2026 amendment opened ADU conversions inside certain existing structures, including detached garages, even where they no longer meet current setbacks. Worth a look if you have an old garage.
At least one ADU
30-A M.R.S. §4364-B requires towns to allow at least one ADU on a lot with a single-family, two- or three-unit home. No owner-occupancy requirement, and that ADU is exempt from density limits.
Town deadlines vary
Maine's ADU rules took effect for towns on January 1, 2024 where the selectmen can amend the ordinance on their own, and July 1, 2024 everywhere else. Some towns are still catching up, so we read the ordinance yours actually has.
Summary only, current as of November 2026. Not legal advice. Local rules still apply and town compliance dates differ. We confirm your town's rules before we quote.
Also from Langone
Not building an ADU?
Excavation & site work
Land clearing, site preparation, drainage and septic across southern Maine and New Hampshire.
Custom homes
Site work and the house under one contract, from the ground up.
New homesCommercial site work
Insured commercial site packages, pads and utilities. Ask whether your project can be bonded.
CommercialInstant pricing
Want a number tonight?
Describe the job in plain English. ADU, custom home, addition, garage, deck, or septic. ADU quotes start from the 10 published models ($147,000–$388,000).
- Based on real Langone ME & NH builds
- Six project types
- About two minutes
Example
What do you want to build?
A 1-bed ADU on my back lot in Sanford…
Recent work
Full portfolioFinished work, photographed on site.
Excavation, septic and finished house work, photographed on Langone job sites rather than bought from a stock library.
How we work
Consult. Plan. Build. Hand off.
- 01
Consult
A free call with Dylan to talk through the land, the scope and the budget.
- 02
Plan
Permits, site plan, septic, utilities and a number you can take to a lender.
- 03
Build
The build runs with an update every week and a job site kept tidy.
- 04
Deliver
Walk-through, punch list and keys. Permits, utilities and the lot set the schedule, so we will not promise a date we cannot hold.
Our service area
Southern Maine and the NH Lakes and Seacoast.
Based in West Newfield, Maine. Southern Maine, the NH Lakes Region, and the NH Seacoast.
Maine
West Newfield, ME
Southern Maine · NH Lakes · NH Seacoast
West Newfield yard
Southern Maine, NH Lakes, NH Seacoast
Start here
Tell us the town and the lot.
Send the address and what you have in mind. We check the town's ADU rules, look at what the lot will carry for septic and access, and come back with a real number, not a range.
The first conversation is free. If the lot will not carry what you have in mind, we will say so rather than sell you a plan that does not fit.
Service area
Towns we build in.
Southern Maine, the NH Lakes Region, and the NH Seacoast.
Sanford, MEKennebunk, MEWells, MEWaterboro, MEAlfred, MELimerick, MEShapleigh, MEActon, MERochester, NHDover, NHWakefield, NHWolfeboro, NHOssipee, NHDurham, NHNewfield, MEAlton, NHLaconia, NHMeredith, NHGilford, NHPortsmouth, NHExeter, NHHampton, NHYork, MELebanon, MEMoultonborough, NHConway, NHFull service area
FAQ
Straight answers.
- How much does an ADU cost in Maine or New Hampshire?
- Langone Site Services publishes 10 turn-key ADU models from $147,000 (The Bean, 384 sq ft) to $388,000 (The Ossipee, 1049 sq ft with 2-car garage). The Newfield is $196,000. The Bentley (750 sq ft + attached garage) is $278,000. Models: The Bean, The Bentley, The Wakefield, The Newfield, The Summit, The Shapleigh, The Spruce, The Washington, Ella's Retreat, The Ossipee. Site conditions and town tap fees can change the number.
- Who does the excavation and septic work?
- Site work and septic are part of the build rather than a separate contract to arrange. Conventional septic in Maine starts at $18,000. Maine design starts at $700. Plumbing and electrical are scheduled and managed as part of the build.
- Do you build custom homes in West Newfield and nearby towns?
- Yes. New and custom homes start at $325/sq ft and go up from there. Land is not included. Site work and the house sit under one contract. We do not publish a four-tier price table.
- What towns do you serve?
- Southern Maine (Sanford, Alfred, Limerick, Shapleigh, Acton, Waterboro, Newfield, the Kennebunks, Wells), the NH Lakes Region (Meredith, Gilford, Wolfeboro, Ossipee, Alton, Laconia), and the NH Seacoast (Portsmouth, Exeter, Hampton, Rochester, Dover, Durham). If your town isn't on the service-area page, call and we'll say yes or no.
- Who owns Langone Site Services?
- Dylan Langone, owner-operator. Founded 2018. Office: 621 Wakefield Road, West Newfield, ME 04095. (978) 987-0089. dylan@langonesiteservices.com.
Tell us about the lot and we will tell you what it will carry.
Send the address, or call and talk it through. There is no charge for that conversation and nothing has to come of it. If the property will not carry what you have in mind, we would rather say so early.Langone Site Services LLC · 621 Wakefield Road, West Newfield, ME 04095·dylan@langonesiteservices.com