Essex County, NJ Accessory Structures: ADU Rules (2026)

Under the New Jersey Municipal Land Use Law (N.J.S.A. 40:55D), zoning power belongs to each municipality, and Essex County's 22 towns and cities each set their own ADU rules. Notable examples: Montclair Township permits ADUs as accessory use in R-O, R-O(a), R-1, and R-2 zones with a minimum size of 300 sq ft and maximum of 800 sq ft or 40% of the principal building's habitable area (whichever is less), one ADU per lot, owner-occupancy of either unit, and a recorded deed notice with Essex County (Code §347, Art. II); South Orange Village adopted an ADU ordinance in 2023 permitting ADUs subject to local conditions; Newark's Title XLI (adopted 11/1/2023 by Ordinance 6PSF-E) treats any indoor space of 250+ sq ft with direct access to a common stairwell or hallway as an additional dwelling unit; East Orange, Irvington, and Bloomfield have not adopted dedicated ADU ordinances and treat accessory apartments under general zoning. New Jersey has no statewide ADU mandate — S2347 (2024-2025 session) died and S1786 (2026-2027) is pending in the Senate Community and Urban Affairs Committee. Always confirm the specific municipal zoning code and seek a Zoning Officer determination before designing a project.