Oyster Bay, NY Accessory Structures: ADU Rules (2026)

The Town of Oyster Bay's zoning code does not authorize a general accessory dwelling unit or garage apartment in its one-family residence districts. 4, one of the Additional Regulations in the RO District, the Residence-Office zone that permits combined residential and office use. There, a lot may carry a maximum of one accessory apartment, and the code requires that an outdoor living area be provided in the rear yard for the apartment's resident or residents. 2, the number of people working in an RO building at one time is capped at one person per 400 square feet of usable nonresidential floor space.

Because the accessory-apartment allowance is written into the RO District's own section rather than into the Town-wide use table, a homeowner in an ordinary one-family residence district, such as an R1-10 zone, cannot add a second dwelling unit on the strength of this section; the zoning use table lists accessory apartments as a use category without a supporting code cross-reference outside the RO District, meaning the RO rule is the only codified path to one.