For Section 3A, “Unit capacity” is a measure of the number of multi-family units that zoning allows as of right based on the capacity of the lots in the district. Although some units may already exist, unit capacity for any given lot may be higher or lower than existing development on the site. Unit capacity is one of the factors that is used to determine if a zoning district is a reasonable size. The Compliance Model must be used to evaluate unit capacity.
The Compliance Model takes the zoning requirements into account, as well as other factors such as lot size, parking requirements, excluded land and open space requirements.
The unit capacity of each lot is measured as if that lot was undeveloped:
Image source: Desegregate CT
Please visit the Section 3A Guidelines from the Massachusetts Executive Office of Housing and Livable Communities website here for more information on unit capacity.