Rochester, New Hampshire
Rochester, NH Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 8/10
Last Updated: 8.28.2024
Image Source: City of Rochester NH
What You Need To Know
ADUs must be accessory to a single-family home, limited to 800 square feet and two bedrooms. ADUs can be part of the main dwelling or in a separate structure, with only one allowed per lot and detached requiring special approval. The property owner must live in one of the units, and at least one parking space is required. Security and caretaker apartments, up to 800 square feet, are allowed in commercial or residential buildings with specific occupancy restrictions.
Type of ADU Permit Required
Permitted as specified in the Tables of Uses (by right or by special exception). Detached units require special exception approval.
ADU Rules
Permitted as specified in the Tables of Uses (by right or by special exception). Detached units require special exception approval.
Accessory to a single-family dwelling and, if detached, must match the architectural style.
Limited to two bedrooms or less.
Maximum size of 800 square feet.
Can be part of the single-family dwelling or in a separate building (e.g., above a garage). If part of the main dwelling, an interior door is required.
Only one ADU is allowed per lot.
The property owner must occupy one of the dwelling units as their principal residence.
At least one parking space must be provided for the ADU.
If there is no municipal sewer, the septic system must meet NHDES requirements for total occupancy.
Exempt from site plan review, but a letter of intent must be submitted to the Building Inspector to confirm compliance with these conditions.
Security apartments (up to 800 square feet) must be attached to or located within a commercial, office, or industrial building. Occupancy is restricted to the business owner, family member, or employee for security purposes. Requires site plan review.
Caretaker apartments (up to 800 square feet) must be attached to or located within a residential or nonresidential building. Occupancy is restricted to the owner, family member, or employee of the principal use. Requires site plan review.