ADU Rules in Moore, Oklahoma

Moore, a suburb of Oklahoma City in Cleveland County, regulates Accessory Dwelling Units (ADUs) through its municipal zoning code. Oklahoma has no statewide ADU preemption law, so Moore's local regulations govern what you can build on your property. Moore has a unique and critically important additional requirement: all new residential construction in Moore must include a storm shelter, enacted in direct response to one of the deadliest tornadoes in U.S. history.

The 2013 EF5 Tornado — Why Moore's Storm Shelter Law Matters

On May 20, 2013, an EF5 tornado — the highest rating on the Enhanced Fujita scale, with winds exceeding 200 mph — carved a catastrophic path through Moore, killing 24 people, injuring hundreds, and destroying or damaging thousands of homes. The tornado directly struck two elementary schools.

In the aftermath, Moore became the first city in Oklahoma — and one of the first in the nation — to mandate storm shelters in all new residential construction. This ordinance means that any new ADU built in Moore must include or provide documented access to an approved storm shelter meeting city and FEMA standards.

If you are building an ADU in Moore, a storm shelter is not optional — it is a code requirement. Contact the Moore Building Division early in your design process to understand current shelter specifications, including structural requirements, minimum dimensions, and accessibility standards (Moore's ordinance follows FEMA P-361 or equivalent).

What Is an ADU?

An ADU is a secondary, self-contained residential unit on the same lot as a primary home — a detached backyard cottage, a garage conversion, an attached in-law suite, or a basement apartment.

Permitted ADU Types

In Moore's single-family residential zones, the city may permit:

• Detached ADUs — standalone structures in the rear or side yard
• Attached ADUs — additions connected to the primary dwelling
• Garage conversions — converting a detached or attached garage to habitable space
• Interior/basement conversions — creating a separate unit within the existing structure

Confirm your property's specific zoning district and ADU eligibility with the Community Development Department.

Size and Setback Guidelines

• Maximum size: Typically limited to a percentage of the primary dwelling's floor area or an absolute cap; verify current limits in the Moore Zoning Code
• Rear setback: Minimum 5 feet from the rear property line is typical
• Side setback: Minimum 3–5 feet from interior side property lines
• Height: Detached ADUs generally limited to one story or approximately 16–18 feet
• Lot coverage: Combined building footprint must not exceed the zone's maximum lot coverage

Storm Shelter Requirement (Critical)

Moore's storm shelter ordinance requires every new residential unit to include an approved storm shelter. Key requirements include:

• Standard: Shelter must meet FEMA P-361 (Safe Rooms for Tornadoes and Hurricanes) or equivalent, rated for EF5-level wind loads
• Accessibility: The shelter must be accessible from the dwelling unit
• Location options: Below-grade in-ground shelters, above-grade safe rooms built into the structure, or standalone prefabricated shelters meeting code
• Inspection: The shelter must pass inspection by the Moore Building Division before CO is issued

Verify current requirements and approved shelter specifications with the Moore Building Division at the time of permit application.

Permit Process

1. Verify zoning: Use Moore's zoning map or contact Community Development to confirm your property's zoning district
2. Storm shelter design: Engage a licensed structural engineer or shelter manufacturer early to design an approved shelter concurrent with ADU plans
3. Prepare construction documents: Hire a licensed architect or designer to prepare full plans including shelter specifications
4. Submit application: File a building permit with Moore Community Development, 301 N. Broadway, Moore, OK 73160
5. Plan review: Staff reviews for zoning compliance, building code, and storm shelter ordinance requirements
6. Permit issuance: Pay fees and receive your building permit
7. Inspections: Schedule required inspections including specific shelter inspection
8. Certificate of occupancy: Obtain a CO — shelter inspection must pass before CO is issued

Contact Information

City of Moore Community Development 301 N. Broadway Moore, OK 73160 Phone: (405) 793-5000 Website: cityofmoore.com/departments/community-development

Disclaimer: ADU regulations change frequently, and Moore's storm shelter ordinance details may have been updated since this page was written. Always verify current requirements — especially the storm shelter requirements — directly with the Moore Building Division and review the current zoning and shelter ordinance before starting any project. This page is for informational purposes only and does not constitute legal or planning advice.