New Market, New Hampshire

New Market, NH Accessory Dwelling Unit (ADU) Rules

City Acceptance Rating: 10/10

Last Updated: 8.28.2024

Image Source: Town of New Market

What You Need To Know

ADUs must be between 200-1,000 square feet, cannot exceed 80% of the main unit's floor area. Only detached ADUs are allowed with manufactured homes. ADUs must maintain design consistency with the primary home, and parking and utility requirements must be met, including water and sewage standards. Bonus space may be granted for installing solar energy systems. Properties with ADUs must submit annual recertification.

Type of ADU Permit Required

An ADU requires only a building permit application unless otherwise required by state statute or the Municipal Code of Newmarket, New Hampshire.

ADU Rules

• Prohibitions: The following ADU-related uses are prohibited:

  1. Leasing the principal residence, the ADU, or both for short-term rental.

  2. Converting an ADU into a condominium or any other form of separate legal ownership.

  3. Converting an ADU into a primary dwelling unit unless it becomes the only dwelling unit on the lot.

  4. Constructing an ADU within the 100-year flood plain.

• Recertification and Retirement of ADUs: All properties with an ADU must submit an annual ADU recertification application. Failure to do so will result in revocation of the ADU's occupancy. If an ADU is abandoned or converted into the primary dwelling unit, the property owner must comply with all applicable regulations.

• Standards: The following standards apply to all ADUs:

  • Occupancy and Ownership:

  • The property owner must occupy either the principal dwelling or the ADU as their primary residence. Residency must be demonstrated by evidence of voter or vehicle registration.

  • When the property is owned by a trust, LLC, or other entities, one dwelling unit must be the primary residence of the trust or LLC beneficiary.

  • Dimensions:

  • Living Area: ADUs must be between 200 and 1,000 square feet and cannot exceed 80% of the primary dwelling unit's gross floor area.

  • Building Setbacks: ADUs must adhere to setback requirements. Exceptions include preexisting accessory buildings and those located at specific distances from the front property line.

  • Density: A single-family lot with an ADU is exempt from maximum residential density requirements.

  • Impervious Surface Coverage: Lots cannot exceed 65% impervious surface coverage due to ADU construction. Exceeding this limit requires compliance with stormwater management regulations.

  • Renewable Energy Systems: A 100 sq. ft. bonus to the maximum ADU size may be applied if a rooftop solar energy system is installed.

  • ADUs on Single-Family Lots with Manufactured Homes: Only detached ADUs (DADUs) are permitted on lots with manufactured homes.

    Building Design:

  • AADUs and ICADUs: ADUs must be subordinate to the primary dwelling in design, maintain aesthetic continuity, and harmonize entrances with the main structure.

  • DADUs: Newly constructed DADUs must appear as accessory buildings while maintaining aesthetic continuity with the primary dwelling. Converted accessory buildings must maintain or improve aesthetic harmony with the main dwelling.

  • Parking: Parking standards for ADUs must be followed, with specific requirements based on lot characteristics.

  • Water Supply and Sewage Disposal: Adequate water supply and sewage disposal must be provided. Applicable fees for town water and sewer must be paid before issuing a building permit or certificate of occupancy. For properties without town sewer, septic systems must meet New Hampshire Department of Environmental Services requirements.

Resources:

https://www.londonderrynh.gov/sites/g/files/vyhlif4616/f/uploads/adz_0.pdf