ADU rules in Tulsa

Tulsa defines an ADU as a dwelling unit in an accessory building (carriage house, garage apartment, mother-in-law flat), one per lot. In the RE and RS single-family districts (RS-1 through RS-5, which cover most Tulsa neighborhoods) and in AG and AG-R, an ADU needs a special exception from the Board of Adjustment after a noticed public hearing. ADUs are allowed by right in RD, RT, RM, RMH and the office, commercial and mixed-use districts when accessory to a household living use, and by right in any district inside the Neighborhood Infill Overlay (NIO), NIO-2 and Neighborhood Character Overlay 2 (NCO-2) areas. The Planning Office's own May 2026 staff summary says Board approvals for ADUs are almost always granted.

No attached ADU use exists: Tulsa's ADU definition covers only a unit 'located in an accessory building', so a basement, internal or attached second unit is instead a second household on the lot. 'Two households on single lot' in a duplex building is prohibited in RE, RS-1 and RS-2, needs a Board of Adjustment special exception in RS-3, RS-4 and RS-5, and is permitted by right in RD, RT and RM-0 through RM-3. Duplex lot and building regulations (minimum lot area and the like) then apply in place of the ADU rules.

Section 45.031-D.6 applies the accessory-building limits of Section 45.030 and raises them by 500 square feet for an accessory building containing an ADU. Section 45.030 caps the total aggregate floor area of all detached accessory buildings at 500 square feet or 40% of the principal house's floor area, whichever is greater, in RS-2 through RS-5, RD, RT and RM, and 750 square feet or 40% in RE and RS-1, so a detached garage on the same lot counts against the same budget. A larger accessory building may be approved by Board of Adjustment special exception. In the rear setback an accessory building with an ADU on the second floor may reach two stories or 25 feet (18 feet to the top plate), and rear-setback coverage is capped at 30% (RE, RS-1), 35% (RS-2) or 40% (RS-3 and up).

Neither the ADU section (45.031) nor the accessory-building section (45.030) contains any owner-occupancy requirement, and a code-wide search of Title 42 for owner occupancy wording returned no zoning hits; the 2019 compiled code shows the 2016 ADU rules never had one either. Oklahoma has no state ADU statute, so this is purely local. The only primary-residence test in the code belongs to accessory-use short-term rentals, not to ADUs.

Section 55.050-D exempts accessory buildings from the minimum off-street parking ratios of Table 55-1, and an ADU is by definition in an accessory building, so the ordinary 1 space per dwelling unit household-living ratio does not attach to it. The CBD district has no minimums at all, and the NIO halves household-living minimums for the principal use.

In RE, RS-1 through RS-5, AG and AG-R (most single-family neighborhoods), an ADU is a special exception: an application to the land use administrator, a staff report, newspaper, mailed (300 feet) and posted notice, and a Board of Adjustment public hearing, roughly 40 days minimum per the City's HOME Catalog guide. In RD, RT, RM, RMH, office, commercial and mixed-use districts, and inside the NIO, NIO-2 and NCO-2 overlays, an ADU is permitted by right with a zoning clearance and building permit; a building in a Historic Preservation overlay also needs an HP permit. A floor-area increase beyond the cap is also a special exception.

The zoning code places no rental or occupancy limit on ADUs, and the ADU purpose statement expressly mentions owners obtaining 'extra income'. Short-term rental as a principal use (a dwelling unit that is not anyone's primary residence) is permitted by right in every R district, and an accessory-use short-term rental covers an occupied home, so a detached ADU can be licensed either way. Every short-term rental needs a City license (expires June 30 each year), a local contact reachable around the clock, a guest register, the license number on all advertising, a maximum of 8 occupants, and no events. No separate-sale rule appears in Section 45.031, but an ADU shares its lot with the house, so selling it apart would require a lot split meeting district lot standards.