3 county-level rules, plus city-specific rules for 3 cities in Johnson County, Kansas.
Verified from official government sources
Kansas has no statewide ADU mandate; ADU regulation is delegated to counties under K.S.A. 19-2901 et seq. Johnson County's Zoning Regulations permit internal, attached, and detached accessory dwelling units (ADUs) by right in rural and residential districts under Article 18, Section 7(D), subject to use-specific performance standards. ADUs are accessory and secondary to a principal dwelling unit and must remain under the same ownership in all respects. Most reviews are administrative; some site conditions trigger a public hearing before the Board of County Commissioners.
Sheds in unincorporated Johnson County must meet county zoning setbacks for accessory structures. Under the county's adopted building code, a permit is generally required for accessory structures over roughly 120–200 square feet or on permanent foundations; rural districts allow larger agricultural buildings.
Converting a garage to living space in unincorporated Johnson County requires a county building permit and zoning review for off-street parking, egress and dwelling-unit standards; creating a separate unit triggers ADU rules.
3 cities in Johnson County have their own accessory structures rules. Each link goes to that city's dedicated page with code citations.
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Johnson County Ordinance Hub →