Langone Site Services builds turn-key ADUs and handles excavation, site work, and septic in Dover, New Hampshire. Dover sits on the Cocheco River in Strafford County. Call (978) 987-0089.
Detached ADUs follow the district setbacks. The front, side, and rear are in the table below. The city can amend the ordinance, so we read the parcel before we price.
Dover is in Strafford County on the Cocheco River. RSA 674:71-73 and HB 577 require one ADU, attached or detached, by right in single-family districts. Shoreland rules can apply near the river.
NH RSA 674:71-73 (HB 577) - one ADU by right on a single-family lot
Dover sits on the Cocheco River. The table is the setback for a house. A detached ADU is an accessory building and gets looser setbacks: 10 ft side and 10 ft rear in all three districts, and in front no closer to the street than the house (40 ft in R-40). Confirm the zone on the city map before you pick a model.
| District | Front | Side | Rear | Lot / cover |
|---|---|---|---|---|
| R-20primaryLow-Density ResidentialBuild-to 20-35 (min 20). Frontage 125 ft. | 20 ft | 20 ft | 30 ft | 20,000 sf · 30% lot |
| R-12Medium-Density ResidentialBuild-to 15-25 (min 15). Frontage 100 ft. | 15 ft | 15 ft | 30 ft | 12,000 sf · 30% lot |
| R-40Rural ResidentialFrontage 150 ft. | 40 ft | 25 ft | 30 ft | 40,000 sf · 10% lot |
Verified 2026-11-14 against Dover Zoning Ordinance, Ch. 170 (district tables, Attachments 1-3; ADUs §170-24). Towns amend ordinances, so confirm with the land-use office before you build. Official source
These three stay at or under 896 sq ft. The 750 sq ft Bentley is the garage option. Size limits vary by town and lot. Call and we'll check yours.
525 sq ft, 1 bed / 1 bath, 30×18, one story.
View this model750 sq ft, 1 bed / 1 bath with an attached garage.
View this model896 sq ft, 2 bed / 1 bath, 32×28, two story.
View this modelThe Wakefield keeps the footprint small. The Bentley is 750 sq ft with an attached garage. The Washington is 896 sq ft. Ella's Retreat is 981 sq ft and The Ossipee is 1,049 sq ft, and both need Dover to allow that size.
Price a Dover ADUThe pad, the utility trench and the access are all part of the same scope. Grade changes get looked at on the lot, not from a map screenshot.
ExcavationDover's older streets are mostly on city sewer. Septic is the rural edge, and we'll price that system after we see the lot.
Septic installationDover site work is older-street access and the Cocheco side, not an open field. The truck path gets walked before a date is committed to.
Site workEvery town we cover is listed on the service area page.
We will read the ordinance against your parcel, look at what the ground will take for septic and access, and come back to you with a figure rather than a range.
