Derry, New Hampshire
Derry, NH Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 8/10
Last Updated: 8.28.2024
Image Source: Derry Community Access Media
What You Need To Know
Attached ADUs only are allowed and can not exceed 800 square feet. The homeowner must occupy the primary residence or ADU.
Type of ADU Permit Required
Permitting By Right if all requirements are met, only standard building permits are needed.
ADU Rules
The lot must meet the minimum area required for its zoning district.
Sewer disposal provisions must comply with state law.
Off-street parking for at least four vehicles is required.
The ADU’s living space cannot exceed 800 square feet.
The ADU must be within or attached to the existing home and have an interior door connecting it to the main dwelling.
Converting a free-standing structure into an ADU is prohibited.
The ADU must include a kitchen, living room, bathroom, and one or two bedrooms.
Room sizes must meet the International Residential Code standards.
Once an ADU is created, no further conversion for additional dwelling units is allowed.
The property and structure cannot be converted into a condominium or other separate ownership.
Any additions for the ADU must match the design of the primary dwelling.
The owner must occupy either the primary or accessory dwelling unit.