Windham, New Hampshire

Windham, NH Accessory Dwelling Unit (ADU) Rules

City Acceptance Rating: 8/10

Last Updated: 8.28.2024

Image Source: Town of Windham

What You Need To Know

Only one attached ADU is allowed per single-family dwelling, with a maximum size of 950 square feet and two bedrooms. The property owner must reside in either the main home or the ADU as their primary residence. ADUs are prohibited in townhouses and manufactured housing. The ADU must maintain the appearance of a single-family residence and the cannot be converted to a condominium or separate legal ownership.

Type of ADU Permit Required

If all requirements are met, only standard building permits are needed.

ADU Rules

  • Only one accessory dwelling unit (ADU) is allowed per single-family dwelling and must be attached.

  • ADUs are prohibited for townhouses and manufactured housing as defined in RSA 674:3.

  • The property owner must occupy either the principal dwelling or the ADU as their primary residence.

  • The property and use must comply with all Town of Windham Zoning Ordinance, Land Use Regulations, and applicable building, life safety, and health codes.

  • The property owner may be required to periodically demonstrate compliance with the Town, with reasonable advance notice.

  • Any exterior entrances of the principal and accessory dwelling units must be designed to maintain the appearance of a single-family residence.

  • An interior door, which may be locked, must be provided between the principal and accessory dwelling units.

  • The ADU may not exceed 950 square feet and can have a maximum of two bedrooms.

  • The principal and accessory dwelling units must share a single driveway.

  • Septic and water systems must meet NH DES and Town requirements for combined or separate systems for both units.

  • Off-street parking must be provided for one additional vehicle.

  • The structure and lot cannot be converted to a condominium or any other distinct form of legal ownership. To ensure compliance, the property owner must execute a restrictive covenant, easement, or development restriction deed in favor of the Town, which must be recorded in the Rockingham County Registry of Deeds and a copy provided to the Community Development Department and the Assessor before a Certificate of Occupancy is issued.

Resources:

https://windhamnh.gov/DocumentCenter/View/14860/2024-Zoning-Ordinance-?bidId=

Convert Existing Space, Attached ADUDeanna DuffeyNew Hampshiure, Friendliness Rating 8/10, Windham