Jackson, NJ Accessory Structures: ADU Rules (2026)

Jackson Township Code § 244-91G, adopted for the RG-3 Regional Growth Zone, sets the bulk standards for accessory dwelling units. An ADU is defined as an additional dwelling unit within a building that is incidental and subordinate to a lawfully permitted principal building containing no more than one principal residential unit on the same tax lot, with no shared cooking, food preparation or sanitary facilities and its own separate entrance. Under the ADU bulk standards, an ADU cannot serve as a basis for increasing a structure's height above what the RG-3 zone otherwise allows, and detached ADUs that are not attached to the principal structure are not permitted at all: every ADU is treated as part of the principal building and must meet the same bulk requirements, including maximum building and impervious coverage.

Only one ADU is allowed per building lot, the lot cannot be subdivided to separate the ADU from the principal structure, and the ADU's floor area and building coverage cannot exceed that of the principal use. Each ADU needs a minimum of two rooms, one of which must be a bathroom, with all rooms accessible from within the unit, and it cannot reduce the parking required for the principal building; a minimum of one parking space is required for the ADU itself, which the Township Engineer may allow to be allocated from an existing driveway.

Owners adding an ADU after the primary dwelling was built must submit a survey, plot plan and architectural plans before a construction or zoning permit issues. Properties with lawfully preexisting nonconforming two-family or multifamily uses cannot add a new ADU. An ADU that meets the Uniform Housing Affordability Control Rules and carries a ten-year affordable-housing deed restriction can have its COAH Residential Development Fees waived.