ADUs are allowed in Unincorporated JohnsonTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Unincorporated Johnson, KS
Is your property eligible for an ADU?
# of Properties
5,602
Owner-occupied
84%
Zoning districts
27
Median Lot Size
2.07 acres
Avg Income
$145,794
Residential Types:
5,602 housing units
Single Family
99%
Apts (4+ units)
1%
Zoning Districts:
9,076 parcels · 27 districts
A
50%(4,527)
SFR
42%(3,786)
I
5%(473)
ROW
1%(85)
Other
2%(205)
ADU Rules
What can you build in Unincorporated Johnson, KS?
Unincorporated Johnson, KS follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum internal/attached ADU size of 50% of the principal dwelling’s livable area.
Detached ADU Size Limits
- –Maximum detached ADU livable area of 900 sq ft
- –Detached ADU must fit within the lot's accessory-building main-floor (footprint) allowance by lot size, after accounting for existing accessory structures
Max Units
- –1 ADU per lot, tract, or parcel (single-family); duplex/multifamily: none specified
Owner Occupancy
- –Owner must occupy either the principal or ADU
Parking
- –1 space/ADU; no max; exceptions: use existing driveway entrances unless a new entrance approved by County Engineer; ADU must be within 200 ft of a driveway for fire access; principal dwelling parking must meet district standards (e.g., 2 spaces per dwelling unit)
Rental Restrictions
- –Cannot rent both units at once; owner-occupied required (waiver possible for absences under 1 year). Short-term rentals require an STR permit and must follow STR rules; ADU may not be operated as a bed-and-breakfast.
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
Check my propertyHow can we help you?
Get matched with trusted local builders
Understand what's allowed on your property
Learn the key rules and size limits for ADUs
Is your property eligible for an ADU?
ADU rules in other Kansas municipalities
Rules change at the town line. Check the municipality your property is actually in.
Johnson County