Olathe permits accessory dwelling units (ADUs) accessory to a principal single-family dwelling in all residential, downtown, and planned districts under Section 18.50.025 of the Unified Development Ordinance. ADUs require a building permit through the Olathe Building Codes Division and must meet size, height, setback, and architectural-compatibility standards administered by the Planning Division.
Olathe regulates ADUs through UDO Sec. 18.50.025, which allows ADUs as accessory to a principal single-family dwelling on the same lot in residential, downtown, or planned districts. Key dimensional standards: maximum gross floor area of 1,000 sq ft or 50 percent of the principal structure's floor area, whichever is less; no more than two bedrooms; maximum height of two stories or the height of the principal dwelling, whichever is less; setback at least six feet behind the front of the principal structure; minimum ten-foot rear-yard setback. The architectural style and exterior materials must conform to those of the principal dwelling. Permits are obtained through the Olathe Building Codes Division (913-971-6200) using forms provided in the Building Permit Application Guide. Olathe enforces the International Residential Code (2018 edition) as adopted under O.M.C. Title 15, with Kansas state amendments. Kansas has no statewide ADU preemption — Kan. Stat. Ann. (KSA) 12-741 et seq. delegates zoning authority to cities, so Olathe controls ADU policy. Johnson County Wastewater (a separate utility) handles sewer connection review where applicable; properties on septic require Johnson County Department of Health and Environment review.
Building an ADU without a permit triggers a stop-work order from the Building Codes Division, double permit fees on after-the-fact applications, and code-enforcement citations under O.M.C. Title 15 and UDO Sec. 18.40.200. Continued violations can result in municipal court prosecution with fines up to $1,000 per day under O.M.C. Sec. 1.08.010.
Olathe, KS
Olathe prohibits storing abandoned, inoperable, or unregistered vehicles on public streets or visible on private property. Vehicles may be tagged and towed a...
Olathe, KS
Olathe regulates electric vehicle charging infrastructure for residential and commercial properties. Building codes may require EV-ready parking in new const...
Olathe, KS
Olathe regulates overnight parking on public streets. Many areas restrict parking between certain hours or require permits for overnight street parking.
Olathe, KS
Olathe requires pool barriers meeting safety codes to prevent drowning. Fences must be at least 4 to 5 feet tall with self-closing, self-latching gates.
Olathe, KS
Olathe requires permits for retaining walls above a certain height, typically 4 feet. Engineering review may be required for taller walls.
Olathe, KS
Olathe restricts or prohibits intentional feeding of wildlife including deer, coyotes, and bears. Feeding wildlife creates public safety hazards and nuisance...
Side-by-side rule comparisons with other cities in Johnson County.
See how other cities in Johnson County handle adu permits.
See how Olathe's adu permits rules stack up against other locations.
Quick Compare
Help us keep this page accurate. If you notice an error or outdated information, let us know.