Owasso's Accessory Structures: The Rules That Matter

Every city handles accessory structures a little differently. In Owasso, Oklahoma, there are 4 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Carport Rules

Owasso treats carports as accessory structures requiring a building permit and, when proposed in a residential district, approval by Special Exception from the Owasso Board of Adjustment. The published Community Development FAQ states 'Carports are permitted by Special Exception, which requires approval from the Owasso Board of Adjustment.' A detached accessory building in a rear yard is additionally limited to 20% of the required rear yard area and 500 square feet of total floor area, and Owasso has adopted the 2018 International Residential Code and 2018 International Building Code as the construction standards.

Key details: Special Exception: Required (Board of Adjustment). Building Permit: Required. Detached Accessory Cap: 500 sq ft / 20% rear yard. Building Code: 2018 IRC / 2018 IBC. Front Setback Encroachment: BOA finding required.

Building a carport without a building permit, without the required Board of Adjustment Special Exception, projecting a carport into the front setback without BOA approval, or exceeding the 500 sq ft / 20% rear-yard cap on detached accessory buildings is enforceable by Owasso Code Enforcement and the Community Development Department. Remedies include stop-work orders, after-the-fact permitting fees, daily civil fines through Owasso Municipal Court, and an order to remove the noncompliant structure.

This is one of the stricter rules in Owasso's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

Garage Conversions

Garage conversions in Owasso require a building permit from Building Services. The conversion must meet Oklahoma Residential Code (2015 IRC) standards for habitable space. Carports require a Special Exception from the Owasso Board of Adjustment. Contact Building Services at (918) 376-1534 to determine specific permit requirements for your conversion project.

Key details: Permit: Building permit required. Building Code: 2015 IRC (OK adoption). Carports: Special Exception required. Contact: (918) 376-1534.

Unpermitted conversion: building code enforcement. Must bring to code or restore. Safety violations: immediate correction.

ADU Rules

Owasso Zoning Code regulates accessory dwelling units through its local zoning ordinance (Ordinance 1131). ADUs may be permitted in certain residential districts subject to local planning department approval. Detached accessory buildings in residential rear yards cannot cover more than 20% of the minimum required rear yard and total floor area cannot exceed 500 sq ft. Contact Planning at (918) 376-1540 for ADU eligibility.

Key details: Zoning Code: Ordinance 1131. Max Floor Area: 500 sq ft (accessory buildings). Max Coverage: 20% of required rear yard. Contact: Planning (918) 376-1540.

Unpermitted ADU: standard building code enforcement. May require demolition or legalization. Occupying unpermitted dwelling: code violation.

Shed Rules

Owasso Zoning Code limits detached accessory buildings in residential rear yards to 20% coverage of the minimum required rear yard with a maximum total floor area of 500 sq ft. Building permits may be required from Building Services at (918) 376-1534. Setback requirements vary by zoning district. Before beginning construction, check with Building Services to determine permit requirements.

Key details: Max Floor Area: 500 sq ft. Max Coverage: 20% of rear yard. Permit: May be required. Contact: (918) 376-1534.

Unpermitted structure: retroactive permit with penalty. Non-compliant setback: modification or removal.

The Bottom Line

Owasso's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Owasso is broadly strict or permissive.

Keep in mind that Owasso can amend these rules at any council meeting. For the most current version of any rule mentioned here, check the specific ordinance page, where we track updates as they happen.