Accessory Dwelling Units (ADU)
Case Study

Northampton, MA

Colloquially called "Paradise City," Northampton is a lively, diverse community located in the heart of Pioneer Valley in western Massachusetts. The city has a strong and diverse economic base consisting of retail, commercial, and manufacturing sectors, three hospitals and Smith College, which is part of the Five-College Consortium. There is an active downtown that has numerous restaurants, clubs featuring an array of music, and street musicians.

Northampton offers a range of housing types: from apartments and condos downtown to single family homes throughout the community. In part due to Northampton’s many amenities, including its strong school system, housing prices have increased significantly. Despite this, Northampton has maintained close to 12% of their housing units as affordable according to the Massachusetts Department of Housing and Community Development’s housing inventory. Accessory apartments offer another housing option—one that can fit the needs of the some of the region’s many students or allow an aging parent to live close to a son or daughter.

Single-family dwelling in Northampton, MA.

Local Accessory Dwelling Ordinance

The City of Northampton first implemented the accessory units ordinance in 1999 and had it apply to all single-family dwellings. Some of the key requirements of the ordinance include:

  • Accessory units within a single-family dwelling are by-right and if the apartment is detached, a Special Permit is required. There are no affordability restrictions required for the permitted accessory dwelling units.
  • The number of tenants is restricted to a maximum of 3 people in the accessory units, but there are no relationship restrictions.
  • Floor area of the accessory units is limited to 900 square feet.
  • There are no specific requirements on setbacks and lot coverage.
  • Three parking spaces are required on the property.
  • Access to the accessory dwelling unit must be from the side or rear yards of the primary building.
  • Units can be specified for handicapped persons.