LD 2003
At least one ADU on a lot with a single-family, two- or three-unit home. That requirement has not moved.
The catalogue10 ADU models,
10 ADU models,
priced up front.
384 to 1,049 sq ft, $147,000 to $388,000, turn-key on a standard lot. Site work and the septic hookup are part of that figure rather than a separate bill later.
- Published models
- 10Published models
- Square feet
- 384–1,049Square feet
- Bedrooms
- 1–2Bedrooms
- On a standard lot
- Turn-keyOn a standard lot
Models & prices
Every plan, with its number.
Pick by size or by budget. Each card opens a full spec sheet with the floor plan.
Size
10 / 10
The Bean
$147,000starting
- sq ft
- 384
- bed
- 1
- bath
- 1
384 sq ft, 1 bed / 1 bath, 16×24, one story.
View this model
The Newfield
$196,000starting
- sq ft
- 600
- bed
- 1
- bath
- 1
600 sq ft, 1 bed / 1 bath, 30×20, one story.
View this model525 sq ft
No exterior render on file · plan set on request
The Wakefield
$216,000starting
- sq ft
- 525
- bed
- 1
- bath
- 1
525 sq ft, 1 bed / 1 bath, 30×18, one story.
View this model
The Summit
$235,000starting
- sq ft
- 654
- bed
- 1
- bath
- 1
654 sq ft, 1 bed / 1 bath, 30×22, one story.
View this model
The Shapleigh
$252,000starting
- sq ft
- 800
- bed
- 2
- bath
- 1
800 sq ft, 2 bed / 1 bath, 40×20, one story.
View this model
The Bentley
$278,000starting
- sq ft
- 750
- bed
- 1
- bath
- 1
750 sq ft, 1 bed / 1 bath with an attached garage.
View this model
The Spruce
$290,000starting
- sq ft
- 882
- bed
- 2
- bath
- 2
882 sq ft, 2 bed / 2 bath, 42×21, two story.
View this model
The Washington
$305,000starting
- sq ft
- 896
- bed
- 2
- bath
- 1
896 sq ft, 2 bed / 1 bath, 32×28, two story.
View this model
Ella's Retreat
$321,000starting
- sq ft
- 981
- bed
- 2
- bath
- 2
981 sq ft, 2 bed / 2 bath, 36×28, one story.
View this model
The Ossipee
$388,000starting
- sq ft
- 1049
- bed
- 2
- bath
- 1
1,049 sq ft, 2 bed / 1 bath, 38×28, two story plus a 2-car garage.
View this modelImages are architectural renderings, not finished job photos. Published figures assume a standard site. Ledge, a long utility run or a town tap fee will move them, and we will tell you which of those apply to your lot before you sign anything.
Every model includes
Premium is the standard spec.
There is no base trim level to upgrade out of. Everything listed here is included in the published figure for every plan in the catalogue.
Underneath the finish sits the site work itself: site preparation, the foundation, utilities and the septic hookup. It is priced alongside the building, so it does not arrive later as a change order.
Shell
- Insulated monolithic slab
- ZIP roof + wall system
- Matthews Brothers windows & doors
- Vinyl siding
- 30-year architectural shingles
Systems
- Mitsubishi mini-split HVAC
- On-demand hot water heater
- R49 ceilings, R23 walls
- Recessed lighting package
- Starlink internet setup
Interior
- LVP flooring throughout
- Tongue & groove pine ceilings
- Hardwood cabinets + granite
- Delta plumbing fixtures
How much does an ADU cost in Maine or New Hampshire?
Langone Site Services publishes 10 turn-key ADU models from $147,000 to $388,000, built in southern Maine, the NH Lakes Region, and the NH Seacoast. The Bean is $147,000 for 384 sq ft. The Wakefield is $216,000 for 525 sq ft. The Newfield is $196,000 for 600 sq ft. The Summit is $235,000 for 654 sq ft. The Bentley is $278,000 for 750 sq ft with an attached garage. The Shapleigh is $252,000 for 800 sq ft. The Spruce is $290,000 for 882 sq ft. The Washington is $305,000 for 896 sq ft. Ella's Retreat is $321,000 for 981 sq ft. The Ossipee is $388,000 for 1,049 sq ft with a 2-car garage. Ella's Retreat and The Ossipee need a town that allows that size. On a standard lot, site prep, foundation, utilities, septic hookup, and finish are included. Site conditions and town tap fees can change the number. Custom homes are a separate product and start at $325 per sq ft, land extra. Call (978) 987-0089 for a number against your own lot.
ADU law · 2025–2026
The statute is the floor. The town is the rest.
Maine still requires an ADU path on lots with a single-family, two- or three-unit home, and New Hampshire now requires one attached or detached unit by right in single-family districts. What changes from town to town is the footprint you can actually stake.
Read the law noteLD 1829 · LD 2173
Density rules and limits on fire-sprinkler mandates for buildings of two or fewer units. 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.
HB 577
Effective July 1, 2025: one ADU by right in single-family districts, and the town must permit a detached unit, with no maximum size below 750 sq ft.
Still local
Setbacks, septic capacity and shoreland overlays decide the footprint. We read the ordinance for your parcel on the consult.
Price my lot
A published figure is not a quote.
Send the address and the model you are drawn to. We check what the town allows, what the ground will carry for septic and access, and come back with a number against your parcel.
Langone Site Services builds turn-key ADUs in southern Maine, the NH Lakes Region, and the NH Seacoast. We handle site prep, foundation, utilities, septic hookup, and finish on a standard lot. Ten published models run from $147,000 to $388,000. Permits, utilities, and the lot set the schedule. Call (978) 987-0089.
Service area
Towns across Maine and New Hampshire.
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, 1,049 sq ft with a 2-car garage). The Newfield is $196,000. The Bentley, 750 sq ft with an attached garage, is $278,000. The other models are The Wakefield, The Summit, The Shapleigh, The Spruce, The Washington, and Ella's Retreat. Site conditions and town tap fees can change the number.
- Are ADUs legal in Maine and New Hampshire?
- Yes. Maine LD 2003 still requires towns to allow at least one ADU on a lot with a single-family, two- or three-unit home. LD 1829 (signed June 20, 2025) and LD 2173 (signed April 16, 2026) add density rules and limit fire-sprinkler mandates on buildings with two or fewer dwelling units. 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, and some towns are still catching up. New Hampshire HB 577 (effective July 1, 2025) requires one ADU by right in single-family districts, and the town must permit a detached unit and bars a maximum size below 750 sq ft. Setbacks, septic, and shoreland still apply. We read your town's ordinance on the consult.
- How long does an ADU take?
- We don't publish a fixed completion promise. Permits, utilities, and the lot decide the schedule. Ask for a timeline on your site.
- 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, so you are not chasing trades.
- 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.
- Do you build ADUs in the NH Lakes Region and on the NH Seacoast?
- Yes. We build turn-key ADUs in the NH Lakes Region, including Meredith, Gilford, Wolfeboro, Ossipee, Alton, and Laconia, and on the NH Seacoast, including Portsmouth, Exeter, Hampton, Rochester, Dover, and Durham. The same 10-model catalog applies. Call (978) 987-0089 if you want to check a specific town.
- What's included in a Langone ADU package?
- On a standard lot, site prep, foundation, utilities, septic hookup, and finish are included. The published package also includes an insulated monolithic slab, ZIP roof and wall system, Matthews Brothers windows and doors, vinyl siding, 30-year architectural shingles, Mitsubishi mini-split HVAC, on-demand hot water, Starlink internet setup, LVP flooring throughout, tongue-and-groove pine ceilings, hardwood cabinets with granite, Delta plumbing fixtures, recessed lighting, R49 ceilings, and R23 walls. Site conditions can change the number. Photos on this page are architectural renders, not finished job photos.
- Where can I see the models and starting prices?
- All 10 models and their starting prices are on the ADU models page, from The Bean at $147,000 to The Ossipee at $388,000. Call (978) 987-0089 or use the form on this page if you want a number for your lot.
Not sure which plan your lot will take?
Book a twenty-minute call and we will look at your lot and come back with a real range rather than a brochure number. dylan@langonesiteservices.com