Washington

Connecticut enacted statewide ADU preemption through HB 6107 (Public Act 21-29), 'An Act Concerning the Reorganization of the Zoning Enabling Act and the Promotion of Municipal Compliance,' signed in 2021. The act amended Connecticut General Statutes § 8-2 to require every municipality that zones under § 8-2 to adopt or amend regulations permitting ADUs as-of-right on the same lot as a single-family home, without zoning variance, special permit, or public hearing. ADUs created under the act are exempt from the municipal base-housing-stock calculation used in the state's Affordable Housing Land Use Appeals Procedure (CGS § 8-30g). The act includes a unique opt-out mechanism: municipalities had until 2023-01-01 to opt out of the as-of-right ADU provision by a two-thirds vote of the legislative body and a two-thirds vote of the planning and zoning commission. Approximately 130+ of Connecticut's 169 municipalities opted out by the 2023 deadline; opted-out towns must still allow ADUs but may write their own (typically more restrictive) regulations. The remaining municipalities operate under the state-floor as-of-right standard.

Connecticut does not operate an ADU-specific statewide loan, grant, or forgivable-loan program. The Connecticut Housing Finance Authority (CHFA) administers a robust portfolio of homeownership programs that can apply to ADU-bearing primary residences, including the flagship Time To Own forgivable down-payment-assistance program. The April 2025 Bond Commission allocated $35M to Time To Own; the program offers up to 20% of purchase price (max $50K in high-opportunity areas, $25K elsewhere) as a 0% interest loan with 10% per year forgiveness over 10 years. The state has also invested $87M across CHFA programs for housing access expansion. None target ADU construction specifically.

• Time To Own Forgivable Down Payment Assistance
• CHFA First-Time Homebuyer and DAP

Connecticut's state-level ADU programs operate primarily through the PA 21-29 preemption framework. The state does not maintain a statewide pre-approved ADU plan catalog. The Office of Policy and Management and the Department of Housing have published guidance and model ADU regulations to assist municipalities that did not opt out, but these are advisory rather than mandatory. PA 21-29's exemption of ADUs from the § 8-30g affordable-housing base-stock calculation is itself an effective state-level incentive, since it reduces the housing-supply leverage municipalities can lose by permitting ADUs. No statewide ADU impact-fee waiver or pre-approved-plan statute exists.

• PA 21-29 § 8-30g Exemption for ADUs