Substitute House Bill No. 7148 seeks to regulate the establishment of accessory commercial units (ACUs) in residential areas by introducing a new definition for ACUs as structures used for commercial purposes that are subordinate to existing residential uses on the same lot. The bill repeals the previous definition of "affordable accessory apartment" in section 8-1a of the general statutes and updates various housing definitions. It mandates that zoning regulations must allow at least one ACU per lot in designated areas and outlines specific conditions for their construction, including exemptions from certain municipal restrictions. Municipalities are required to adopt or amend regulations by October 1, 2026, to comply with these new provisions, and if they fail to do so, existing noncompliant regulations will be void.

Furthermore, the bill streamlines the approval process for ACUs by allowing them to be approved without public hearings or discretionary zoning actions, and it requires municipalities to permit ACUs as of right on at least 33% of residentially designated land. It prohibits municipalities from imposing additional standards beyond those specified in the bill, including restrictions on height and design, and ensures that utility connections for ACUs are not billed separately from the residential property. The bill also restricts certain commercial activities within ACUs, such as drive-through facilities and the sale of alcohol and cannabis, while preventing municipalities and utility authorities from treating ACUs as new uses for calculating connection fees or capacity charges. The effective date for these regulations is set for October 1, 2025.