Kansas S.B. 418 requires cities and counties to approve qualifying single-family homes (including duplexes), townhouse projects of up to 12 attached units, and ADUs by right—without a planning-commission or zoning-board vote—if they meet the existing zoning code and land-use rules. A complete application is deemed approved unless denied within 30 days (60 days if it needs a subdivision plat; 90 days for a plat of more than 40 homes). Projects that need federal or state discharge permits or stormwater drainage studies, or that sit in historic districts, don't qualify.
What "discretionary hearing" actually costs
Before S.B. 418, a duplex or ADU that needed a special-use or conditional-use permit went to a public hearing and a discretionary vote before the building permit could move.
The hearing itself wasn't just a time cost — it was a veto-point cost. S.B. 418 removes the commission's discretion for qualifying projects — if the site is zoned for the use and the project meets the zoning code, land-use rules, and the Act's conditions, it must be approved.
The statute's deemed-approval clock—30 days for most applications—puts a ceiling on how long the zoning side can take.
The lot-size reduction for smaller homes
S.B. 418 also requires every city and county to allow a minimum lot size of 3,000 square feet (with reasonable setbacks) for new single-family homes under 2,500 square feet of livable floor area on their own lots. For those homes, local governments must also allow the 2018 IRC, single-car garages, and architectural finish on only one side.
Subdivision plats still have to meet subdivision regulations, but under the Act a plat application is deemed approved if not denied within 60 days (90 days for more than 40 homes), and the 3,000-square-foot lot floor applies to homes under 2,500 square feet.
For drafters working subdivision plats, the 3,000-square-foot floor changes the lot-yield math on small-home projects—run the yield against local setbacks, streets, and utilities.
How this compares to other state by-right mandates
Several states now require local governments to allow ADUs or middle housing. Kansas took a different route: S.B. 418 doesn't rezone land, but where local zoning already allows a home, townhouse, or ADU, the approval has to be administrative and on a clock.
Kansas's rule applies statewide, to cities and counties of all sizes.
Where local zoning already allows duplexes, townhouses, or ADUs, they're now on the same administrative track: file, get reviewed against the written rules, and get a decision on a deadline.
Who uses this first
Three client types get immediate value:
1. Infill duplex developers in Wichita, Overland Park, and Lawrence can file duplexes by right where the lot's zoning already allows them—no special-use permit or hearing—as long as the project meets the written standards.
2. ADU buyers adding rental income to existing single-family homes. If local zoning allows an ADU on the lot and the unit meets the written standards, the approval is by right—no conditional-use hearing. Check first: S.B. 418 doesn't require a city to allow ADUs where its zoning doesn't.
3. Townhome developers testing attached product in suburban markets. S.B. 418 requires by-right approval of townhouse projects of up to 12 attached units where the underlying zoning allows attached units—so a developer working in Olathe or Lenexa can file a qualifying townhouse project without a discretionary hearing.
Some by-right statutes actually remove friction for multifamily and ADU projects; others just rename the approval process. Kansas S.B. 418 does the former — it takes qualifying single-family, duplex, townhouse, and ADU projects that meet existing zoning off the discretionary track and puts them on an administrative track with a deadline and no neighbor-veto hearing. If you're quoting duplex infill, townhome clusters, or ADU work in Kansas now, you lead with that: no hearing, no special-use permit, and a decision on a clock for projects that meet the written rules.
Questions about how S.B. 418 applies to a specific Wichita or Overland Park site, or whether a townhome project qualifies as by-right under the new statute? Start here. We take projects in all 50 states.