MD HB1538

Local jurisdictions must adopt laws by October 1, 2026 authorizing at least one internal accessory dwelling unit (basement, attic, or garage conversion) and one external accessory dwelling unit (backyard cottage, carriage house, or modular unit) on single-family residential lots, regardless of local density limits.

Off-street parking requirements cannot be imposed for ADUs created by converting existing space within the primary home or an existing accessory structure on the property.

Utility providers cannot charge water/sewer connection fees exceeding administrative permit costs, or capacity charges/tap fees, for ADUs occupied by qualified family members (parents, grandparents, children, grandchildren, or siblings, including through adoption or marriage).

Counties and municipalities cannot impose development excise taxes or development impact fees on ADUs measuring less than 1,000 square feet.

ADUs occupied by qualified family members are exempt from property tax, effective for taxable years beginning after June 30, 2026.