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Shawnee County, KS Accessory Structures: ADU Rules (2026)

Significant Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

ADU rules in Shawnee County, KS, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Governing provision: Zoning Regs Sec. 1.09(c)(4)a.ii, adopted 2006
Second dwelling allowed: Only as temporary hardship exception, not by right
Time limit: Maximum 18 months, then must be removed
Approval authority: Shawnee County board of commissioners
Application requirement: Notarized affidavit justifying hardship or necessity
District affected: RA-1 Rural Agriculture District

ADU Eligibility Quick-Check

An Accessory Dwelling Unit (ADU) is a smaller, independent living unit on the same lot as a single-family home: converted garages, detached cottages, basement or attic conversions, and attached additions all qualify. Most states have streamlined ADU permitting since 2020, but local rules still control size, height, and setback.

Is your lot zoned single-family or multi-family residential?
Does your lot have at least 1,200 sq ft of buildable space?
Is your existing home owner-occupied (in most states this is not required, but some require it for ADU permits)?
Will the ADU stay under your state's size cap (commonly 850-1,200 sq ft for detached)?
Can you provide one off-street parking space (waived in many states within 0.5 mi of transit)?

If you answered 'yes' to most of these, you likely qualify in Kansas under recent ADU streamlining laws. The Shawnee County, KS rules below cover local size, height, and setback requirements.

Summary

Shawnee County's RA-1 Rural Agriculture District zoning bars a second permanent dwelling on one lot. The only path to a second home is a temporary hardship exception: the county may allow a manufactured home as a second dwelling for up to 18 months, granted by the board of commissioners under a notarized affidavit, per Zoning Regulations Sec. 1.09(c)(4)a.ii, adopted 2006.

These county ordinances apply to unincorporated areas of Shawnee County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

ii. The temporary placement of a manufactured home as a second dwelling on an existing lot or parcel, in instances of extreme hardship or necessity, not based on financial considerations, as determined by the board of commissioners, provided: (a) The applicant shall justify and attest to the hardship or reason for requesting said exception in a notarized affidavit; and (b) The applicant shall agree that the exception may be granted for a one time period not to exceed 18 months; provided, however, that at such time the hardship or reason of necessity shall cease and become null and void and the temporary manufactured home shall be removed.

View official code

Full Breakdown

R. Resolution No. 2006-8, treat a detached accessory living unit or "garage apartment" as a second dwelling, and Sec. 09(a) of the Zoning Regulations requires every building to conform to the use regulations of its district: RA-1 Rural Agriculture District permits only one detached single-family dwelling per lot under Sec. 02(a)(3). There is no by-right ADU or garage-apartment allowance. The one route around that limit sits in Sec. " The same subsection, Sec. i, separately allows straight replacement of an existing single-wide mobile home or manufactured home with another manufactured home on the same lot, but that is a replacement, not a second unit.

Any exception granted must still comply with the county's wastewater management plan and all other zoning restrictions. The Shawnee County zoning administrator enforces these use restrictions, with appeals running to the board of zoning appeals under Sec. 11.

Violations & Fines

Placing a second dwelling or manufactured home on an RA-1 lot without a granted hardship exception is a zoning use violation the county zoning administrator can cite under Sec. 1.09(a), since the structure fails to "conform to the regulations for the district." If a hardship exception expires after 18 months and the temporary manufactured home is not removed, the placement becomes an unpermitted use subject to enforcement. Appeals from the zoning administrator's decisions go to the board of zoning appeals under Sec. 1.11.

Frequently Asked Questions

Can I build an accessory dwelling unit or garage apartment in Shawnee County?

Not by right. Shawnee County's RA-1 Rural Agriculture District zoning, under Sec. 1.09(a), lets only one detached single-family dwelling per lot. A second unit is possible only through the hardship exception in Sec. 1.09(c)(4), which covers a temporary manufactured home, not a permanent garage apartment or ADU.

How long can a hardship second dwelling stay in Shawnee County?

Under Zoning Regulations Sec. 1.09(c)(4)a.ii, the county board of commissioners can grant the exception "for a one time period not to exceed 18 months." After that period the hardship or necessity is considered to have ended and the temporary manufactured home must be removed from the lot.

Who approves the second-dwelling hardship exception?

The Shawnee County board of commissioners decides whether the hardship or necessity is real and "not based on financial considerations." Applicants must submit a notarized affidavit justifying the request, and the zoning administrator enforces the resulting permit conditions under Sec. 1.09 of the county's Zoning Regulations.

Sources & Official References

[1]Shawnee County Zoning Regulations, Article I, Sec. 1.09

Other rules in Shawnee County

Shed & Carport RulesSome Restrictions Garage ConversionsSome Restrictions Noise Ordinances: Amplified Music & Outdoor SoundSome Restrictions Noise Ordinances: Barking DogsSome Restrictions Parking Rules: Driveway RulesSome Restrictions Parking Rules: Abandoned VehiclesSome Restrictions Animal Ordinances: Bird ProtectionHeavy Restrictions Animal Ordinances: Cat RulesFew Restrictions

All Shawnee County rules

How Shawnee County compares: Easiest Cities to Build an ADU·Compare Shawnee County to another location·View the Kansas accessory structures overview

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