Cincinnati, OH Accessory Structures: ADU Impact Fees (2026)

Cincinnati has no general impact fee on residential ADUs. Unlike California, Arizona, or some Florida cities, Ohio Revised Code does not authorize municipalities to impose school, park, fire, or library impact fees on residential development. Cincinnati's permit cost structure relies on DBI permit fees scaled to construction valuation. Standard fees: zoning compliance fee ($150-$300), building permit (typically $8-$12 per $1,000 of construction value with $50-$100 minimum), separate trade permits for plumbing, electrical, and mechanical ($75-$250 each). Greater Cincinnati Water Works (GCWW) tap fees apply only if a new water service tap is required - typically $1,500-$5,000. Metropolitan Sewer District of Greater Cincinnati (MSD) tap-in fees apply only if a new sewer lateral is required - typically $1,500-$4,000. ADUs sharing the existing house service avoid GCWW and MSD capacity charges. Historic district properties pay Historic Conservation Board application fees of $100-$500. Hamilton County property tax reassessment applies after construction.