Fairfield County, CT Accessory Structures: ADU Rules (2026)

Connecticut counties have had no operational government since the County Manager Act was repealed in 1960. All land-use authority in Fairfield County rests with the 23 individual municipalities. The state framework is Conn. Gen. Stat. Sec. 8-2, the zoning enabling act, as amended by Public Act 21-29 (HB 6107) in 2021. PA 21-29 requires towns that zone under Sec. 8-2 to permit ADUs as of right on the same lot as single-family homes, meaning without a variance, special permit, or public hearing, unless the town has affirmatively opted out under the statutory procedure (a two-thirds vote of the legislative body and the planning and zoning commission). ADUs created or permitted after January 1, 2022 that lack affordable-housing deed restrictions do not increase a municipality's base housing stock for the affordable-housing percentage under Conn. Gen. Stat. Sec. 8-30g. In practice, large Fairfield County towns vary: some (like Stamford) have aligned their regulations with the as-of-right standard; others (like Greenwich and Darien) retain stricter conditional or special-permit pathways or have invoked the opt-out process. Because the regulatory regime is town-level, applicants must consult the specific town's planning and zoning office.