Hudson, New Hampshire
Hudson, NH Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10
Last Updated: 8.28.2024
Image Source: Town of Hudson
What You Need To Know
An ADU is only permitted in single-family homes and cannot be detached and must maintain the appearance of a single-family home, and new ADU entrances must be on the side or rear. . The property owner must live in either the main dwelling or the ADU. A minimum of four off-street parking spaces is required, with no separate driveway for the ADU. The ADU must be between 350 and 750 square feet, with a maximum of two bedrooms. Only one ADU is allowed per lot, housing no more than two unrelated occupants.
Type of ADU Permit Required
Special permit required.
ADU Rules
An ADU is only allowed in single-family dwellings and is not permitted in two-family or multifamily dwellings, or in any nonresidential structures.
An ADU cannot be a freestanding detached structure or part of any structure detached from the main dwelling. Manufactured housing, RVs, or trailers cannot be used as ADUs.
The owner must occupy either the main dwelling or the ADU. The owner must prove residency in one of the units if requested by the Zoning Administrator.
After modifications, the front of the main dwelling must still look like a single-family home. Any new entrances for the ADU must be on the side or rear of the structure.
There must be at least one shared interior access between the main dwelling and the ADU, with two external exits for each unit.
Separate utility connections or meters for the ADU and the main dwelling are not allowed, except as required by code for common areas.
A minimum of four off-street paved parking spaces must be provided for both the main dwelling and the ADU. There cannot be a separate driveway for the ADU.
The ADU must be between 350 and 750 square feet, and the main dwelling must remain at least 850 square feet after the ADU is added.
An ADU cannot have more than two bedrooms.
A building permit is required before constructing or converting space into an ADU.
The ADU must share the same house number as the main dwelling, and no separate mailbox is allowed.
Only one ADU is allowed per lot in any district.
No more than two unrelated persons can occupy an ADU.
The ADU must have an interconnected fire alarm system with the main dwelling.
The ADU must meet water supply and sewage disposal standards under RSA 485-A:38, but separate systems are not required. Verification must be filed with the Town before a building permit is issued.