Substitute House Bill No. 7148 seeks to regulate accessory commercial units (ACUs) in residential areas by introducing new definitions and requirements. The bill defines an "accessory commercial unit" as a structure used for commercial purposes that is subordinate to an existing residential use on the same lot. It repeals the previous definition of "affordable accessory apartment" and other related terms in section 8-1a of the general statutes. The legislation 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.

Furthermore, the bill requires municipalities with zoning authority to adopt or amend regulations to permit ACUs as of right on at least 33% of land designated for residential use by October 1, 2026. It streamlines the approval process by allowing ACUs to be approved without public hearings and prohibits municipalities from imposing additional standards beyond those specified in the new regulations. The bill also ensures that ACUs are not treated as new uses for calculating utility connection fees or capacity charges, thereby preventing potential revenue loss for municipalities. The effective date for these regulations is set for October 1, 2025, with compliance required by the following year.