Rockland County, NY Accessory Structures: ADU Rules (2026)

Rockland County accessory dwelling unit rules are set by town zoning with no state preemption (Governor Hochul's 2022 Plus One ADU proposal was withdrawn after suburban NY opposition, largely led by Rockland and Westchester). Clarkstown Town Code §290 generally requires single-family use in residential zones, with accessory apartments permitted only in select districts via special permit with owner-occupancy requirement. Ramapo Town Code §376 permits accessory apartments in limited districts subject to minimum lot size (typically 20,000+ sq ft), owner-occupancy, off-street parking, and special use permit from ZBA. Orangetown Chapter 43 allows accessory apartments by special permit in certain zones with strict conditions. Village of Nyack has a more permissive accessory apartment provision in response to housing demand. Illegal basement and garage conversions are a major enforcement issue in Ramapo (particularly Monsey, Spring Valley, New Square, Kaser) where multi-generational living conflicts with single-family zoning. Fatal basement fires (including the 2021 Spring Valley assisted living fire) have increased enforcement. NYS Uniform Building Code (19 NYCRR Part 1220) requires proper egress, ceiling height (7 ft minimum), natural light, and ventilation. Building department inspections and Certificate of Occupancy amendments required.