ADU Pass
Olathe
Johnson County portion
Also in: No County
ADU Pass helps homeowners in Olathe, Johnson County, Kansas navigate the permit paperwork for building an accessory dwelling unit. This area covers 2 ZIP codes.
Map
ADU details
ADU legality: unclear
Kansas leaves ADU regulation to local municipalities under home-rule or Dillon-rule authority. Olathe permits ADUs subject to local conditions per its zoning ordinance.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 150 | $1,500 | $36,750 | $38,250 |
| 600 | 600 | $1,500 | $147,000 | $148,500 |
| midpoint | 525 | $1,500 | $128,625 | $130,125 |
| maximum | 900 | $1,500 | $220,500 | $222,000 |
Fee breakdown
Viability (permitted uses)
- Long-term rental: yes Long-term rental of ADU generally permitted; landlord-tenant law and any city rental-registration ordinance apply.
- Short-term rental: with-restrictions STR rules vary by city. Olathe regulates STRs separately from ADU permitting; check local STR ordinance and HOA covenants.
- Office rental: with-restrictions Detached office rental requires home occupation permit or rezoning.
- Home office: yes Home occupation permitted with restrictions on signage and customer traffic.
- Studio / workshop: yes Personal artist studio is a permitted accessory use.
- Agriculture: with-restrictions Limited urban agriculture permitted in residential zones; livestock varies by district.
- Relative support: yes Family-occupancy ADU explicitly permitted in single-family zones.
Utilities
- Water: Olathe Water Utility · 30d connect · $4,500
- Sewer: Olathe Sewer / Wastewater · 30d connect · $5,500
- Electric: Olathe Electric Utility · 21d connect · $1,800
- Gas: Olathe Gas Utility · 30d connect · $1,500
Property values & taxes
Construction timeline
Realistic total: best 7mo · typical 10mo · worst 16mo
Financing
State ADU loans:
Insurance impact
HOA prevalence & preemption
Kansas has no HOA-ADU preemption; HOA covenants restricting ADUs are enforceable.
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
Legal history (timeline)
Current ordinance: City of Olathe Municipal Code — Accessory Dwelling Units, adopted 2020-01-01, last amended 2024-04-01
- 2024-01-01 — City of Olathe ADU code refresh (city-ordinance)
Conforming local-code amendments aligning with current Kansas accessory-dwelling framework.
Effect: Codified permissive ADU standards consistent with state law and local zoning.
Johnson County — county ADU rules and overlays
County ADU ordinance
Johnson County, KS (620,000 residents in suburban Kansas City) administers a county zoning ordinance for unincorporated territory. Major incorporated cities include Overland Park, Olathe, Lenexa, Shawnee, Leawood, Mission, Prairie Village, Gardner, Spring Hill, De Soto. Each sets its own ADU rules.
State-floor overlay: Kansas has not enacted statewide ADU preemption.
County regulatory overlays
Johnson County administers flood-hazard, and (where mapped) coastal, wildland-fire, historic, and airport overlays that shape ADU project feasibility. The most consistent overlay across the county is FEMA NFIP floodplain regulation; other overlays apply to specific geographies inside the county.
- FEMA NFIP Special Flood Hazard Areas in Johnson County — A new ADU in a mapped SFHA must be elevated to or above the Base Flood Elevation; cost impact on the project is often material.
- Historic districts and individually-listed historic resources
County permitting (unincorporated parcels)
Johnson County issues building permits for parcels in unincorporated territory through its development services / planning department, with separate review tracks for zoning conformance, building-code compliance, on-site sewage where applicable, floodplain compliance, and addressing. Inside incorporated municipalities, city departments handle their own permits; the county's authority is geographically limited to unincorporated territory. An ADU permit application is typically processed as a residential building permit with a zoning verification step against the county's ordinance for the parcel's zoning district.
Kansas state — ADU law and programs
State ADU law
Kansas enacted statewide ADU-permissive housing legislation in the 2026 session. Senate Bill 418, the By-Right Housing Development Act, was signed by Governor Laura Kelly on 2026-04-08. The bill requires every Kansas city and county to ministerially approve housing developments — including single-family homes, townhouses, and accessory dwelling units — that meet existing local zoning code criteria, without discretionary review. Rezoning to single-family residential cannot be subject to double super-majority protest-petition review. Third-party private inspectors are permitted when the local government does not perform required inspections within 15 days of request. The bill follows the Pacific Legal Foundation model 'By-Right Housing Development Act' and 'Fair Zoning Act'. SB 418 does not preempt local zoning standards (size, setback, parking, etc.), but it forces ministerial approval where standards are met.
State financing programs
Kansas does not operate an ADU-specific statewide loan, grant, or forgivable-loan program. The Kansas Housing Resources Corporation (KHRC) administers general first-time-homebuyer, down-payment-assistance, weatherization, and rural-home-loan-guarantee programs. The First Time Homebuyer program offers a 0% interest second mortgage of 15% or 20% of purchase price, forgiven after 10 years of occupancy. None target ADU construction directly; an ADU may be financed through standard rehab or construction-loan products if part of a qualifying primary-residence purchase or refinance.
State housing programs
Kansas's primary state-level ADU program is the SB 418 (2026) By-Right Housing Development Act, which mandates ministerial approval of conforming ADU applications and permits third-party inspection when local agencies miss the 15-day inspection window. There is no statewide pre-approved ADU plan catalog, no statewide ADU rebate program, and no statewide ADU impact-fee waiver. The SB 418 ministerial-approval requirement is the dominant state-level intervention.
- SB 418 By-Right Housing Development Act — Cities and counties must approve single-family homes, townhouses, and ADUs that meet existing zoning standards ministerially, without discretionary review. Bars double super-majority protest-petition review for rezoning to single-family residential.
- SB 418 Third-Party Inspection Provision — When a local government fails to perform a required residential inspection within 15 days of request, the developer/owner may engage a qualified third-party inspector. Removes city/county inspection-backlog as a permit bottleneck for ADUs.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Codes
- 66061
- 66062
Post Office
- 110 N Chestnut St, 66061
- 15050 W 138th St, 66062
Locale Names
- Olathe East