Colonie, NY Accessory Structures: ADU Rules (2026)

Beyond the ownership and occupancy conditions in § 190-22B(1), the Town of Colonie's zoning code sets baseline design standards for every accessory dwelling unit in § 190-22B(2). Subsection (2)(a), "Number," provides that there shall only be one accessory dwelling unit per building lot and that it shall be attached to the single-family dwelling. That rules out detached backyard cottages or garage apartments not physically attached to the principal house, and it caps every lot at a single accessory unit regardless of lot size. Subsection (2)(b) requires the ADU to comply with the dimensional requirements that apply to the single-family dwelling in the zoning district in which it is located and to include all finished space as defined in § 190-6, tying the unit's setbacks, height, and lot coverage to whatever the underlying zoning district already requires for the main house, and to the dimensional table in the code's Attachment 2.

Subsection (2)(c) adds a parking mandate: each dwelling unit shall have two designated off-street parking spaces meeting the standards of this chapter and conveniently located for access to the dwelling unit, meaning the ADU generates its own two-space parking requirement on top of whatever the principal dwelling already needs. Subsection (2)(d) bars installing a second water meter and requires water supply and sewage disposal capacity sufficient for the added unit before conversion is approved.