ADU rules in Wilmington, DE — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
Accessory dwelling units (ADUs) in Wilmington are subject to zoning review under Ch. 48. The city has been updating rules to allow more infill housing, but ADUs require permits and must meet zoning standards.
Wilmington's zoning code (Ch. 48) allows ADUs in some residential districts, typically as attached additions or garage conversions. A zoning permit and building permit are required. ADUs must meet setback, lot coverage, and design standards. Owner-occupancy of the primary dwelling may be required. The Delaware Dillon's Rule framework means Wilmington has authority to establish its own ADU regulations.
Unauthorized ADU construction (including unauthorized garage conversions) violates Ch. 48 and building code, resulting in stop-work orders and fines.
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See how Wilmington's adu rules rules stack up against other locations.
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