Passaic, NJ Accessory Structures: ADU Rules (2026)

Under § 317-16G, an ADU is allowed only on a lot with a one-family or two-family principal residence, and the unit cannot eliminate any existing on-site parking. Physically, the ADU must be located in an attic, basement, ground floor beneath the primary unit, or above a garage, but it may not be situated in a cellar, a distinction the code draws explicitly between a habitable basement level and a true below-grade cellar. Size is capped at 50% of the principal dwelling's living area, with a floor of 300 square feet and a ceiling of three bedrooms.

Only one ADU is allowed per lot, and it must be used solely for residential purposes. Where the ADU attaches to the principal single-family or two-family dwelling, § 317-16G(7) requires it to use the same exterior materials and colors as the principal structure, and the code directs the design to preserve the physical housing stock and the architectural and landscaping character of the neighborhood. Accessory structures generally, including ADUs, cannot exceed the maximum height allowed in the zone for a one- or two-family structure, and no accessory structure of any kind may be built on a lot that lacks a principal building. Every ADU also carries a twenty-year deed-restricted affordability requirement tied to HUD income and rent limits, addressed separately at § 317-16G(9).