ADU laws in Oklahoma

In plain words

Oklahoma has no state law about ADUs. An ADU, or accessory dwelling unit, is a small second home on the same lot as a house. It might be a backyard cottage, a garage apartment, or a suite inside the house. In Oklahoma, each city and town decides through its zoning. Zoning is the local rulebook for what can be built where. Some counties zone land outside city limits, but many rural areas have little zoning. The biggest cities handle ADUs very differently. Oklahoma City began allowing backyard units in its urban core in June 2025. There, you apply with a regular building permit, and units can be up to 950 square feet. Tulsa allows one ADU per lot. In its single-family zones, though, you must ask the Board of Adjustment for a special exception. A special exception is a case-by-case approval that requires public notice and a hearing. Norman has allowed ADUs in several residential and farm zones since 2024. In its main single-family zones, the limit is 650 square feet. State lawmakers filed a few zoning bills in 2025 and 2026. One would have made larger cities allow more housing types. Two others would have stopped cities from requiring a set number of parking spaces. None of them passed. So the rules where you live depend on your city or county. Before you plan, call the local planning office. Check your deed and any HOA rules too. You may be able to build only if local rules and your property allow it.

The rules at a glance

What to do next

1. Find out whether your lot is inside city limits; if so, the city's zoning code decides whether an ADU is allowed and how it is approved.
2. Look up your zoning district on the city's map, then read the ADU or accessory-building section of the code for size, height, setback and parking rules.
3. Ask the planning office whether your district allows an ADU with just a building permit or requires a hearing, such as Tulsa's special exception.
4. If you are outside city limits, ask the county whether your area is zoned, and contact the county health department early if you will need a septic system.
5. Read your deed and any HOA covenants; private restrictions can ban a second unit even where zoning allows one.
6. Get every required zoning approval and building permit before construction starts.

What your town still decides

Oklahoma has no statute about ADUs. Cities and towns zone under the municipal zoning chapter of Title 11 (11 O.S. § 43-101 and following; § 43-103 lists the purposes zoning must serve), and each one decides whether a second home on a lot is allowed and how it is approved. Outside city limits, some counties have planning and zoning and many rural areas have little or none, so building codes, septic rules and private covenants often decide the question there. Approaches in the largest cities differ sharply: Oklahoma City allows backyard units with a building permit but only in its urban core; Tulsa allows them by right in some districts but requires a Board of Adjustment special exception (a public hearing and vote) in its single-family, estate and agricultural districts; Norman allows them in several residential and agricultural districts through a building permit. Bills filed in the 2025-2026 Legislature that would have loosened local zoning or parking rules all died when the 60th Legislature ended in 2026, and the House now lists only 2027 session deadlines. The Legislature's full-text search of every bill version from the 2023-2024 and 2025-2026 sessions finds no use of 'accessory dwelling', 'accessory apartment', 'granny flat', 'secondary dwelling' or 'guest house'.

Examples of local rules

• Oklahoma City: An ordinance adopted May 20, 2025 and in effect since June 20, 2025 allows one accessory dwelling per parcel in areas planned as Urban Medium or Urban High, roughly the city core bounded by I-35, I-44/Northwest Expressway and SW 59th Street. Owners apply for a residential building permit. Units are capped at 950 sq ft and 25 feet tall, must keep the existing front, side and rear setbacks, and buildings plus paving may cover no more than half the lot. A parking space is required only when the street is narrower than 26 feet or the unit is larger than 600 sq ft. Lots in historic preservation or landmark districts need a rezoning and Historic Preservation Commission approval. Outside the covered area the new rules do not apply. Source
• Tulsa: Under Zoning Code § 45.031 (code dated October 21, 2025), an ADU is a dwelling unit located in an accessory building, and only one is allowed per lot. In RE, RS, AG and AG-R districts it needs a special exception from the Board of Adjustment, which involves mailed, posted and newspaper notice and a public hearing; in other districts it is allowed by right when accessory to a household living use. The accessory-building floor area limit (in RS-2 through RS-5, 500 sq ft or 40% of the house, whichever is greater) is raised by 500 sq ft for a building containing an ADU. The unit must sit at least 10 feet behind the house and match the house's exterior materials and roof pitch. Source
• Norman: Ordinance O-2324-40, adopted in March 2024, allows ADUs in the A-1, A-2, RE, R-1 and R-1-A districts through a building permit. In R-1 and R-1-A an ADU may have no more than 650 sq ft of total living area; in the other districts it must be clearly smaller than the main house. Units under 650 sq ft need no off-street parking. Separate water meters are not allowed, a separate electric meter may be allowed by the utility, and the unit is addressed as 'Unit 2' of the main address. Source

What we’re still confirming

• Tulsa's code defines an ADU as a unit in a separate building, so ask whether an attached or inside unit counts as an ADU or as a two-family home.
• Norman describes a building-permit process for ADUs but doesn't say outright that no zoning hearing is needed; confirm with the city.

Laws, bills and citations

This is general information, not legal advice. Your town, village, city or county decides what can be built on your property. If something here looks out of date, email the team.