ADU Rules in Cape Girardeau, Missouri

Cape Girardeau is the county seat of Cape Girardeau County and the largest city in southeast Missouri, situated on the west bank of the Mississippi River. With a population of approximately 40,000, it is the regional hub for healthcare, retail, and education in the "Bootheel" region of southeast Missouri. Southeast Missouri State University (SEMO) is located here, creating rental housing demand similar to other Missouri university towns. ADU regulations are governed by the city's local Code of Ordinances. Missouri has enacted no statewide ADU preemption law.

Missouri State Law

Missouri has no statewide ADU preemption statute. Cape Girardeau sets its own ADU rules through its local Code of Ordinances, zoning chapter.

Permitted ADU Types

Cape Girardeau's zoning code addresses accessory dwelling units in residential districts. Permitted types may include:

• Detached ADU: A freestanding structure on the same lot as the primary dwelling, typically in the rear yard.
• Attached ADU: An addition to the primary dwelling creating a separate, self-contained dwelling unit.
• Garage Conversion: Converting an existing garage into habitable ADU space.
• Basement or Interior Conversion: Adapting existing interior space within the primary structure — particularly relevant in Cape Girardeau's older hillside neighborhoods.

Permitted types and applicable standards vary by zoning district. Contact the Planning and Zoning Department to confirm what is permitted on your specific parcel.

Size, Setbacks, and Height

Dimensional standards are set by the applicable zoning district. General reference:

• Maximum size: Typically a square footage cap or percentage of the primary dwelling's floor area per district standards.
• Setbacks: Rear and side yard setbacks for detached accessory structures are district-specific; commonly 3 to 5 feet.
• Height: Detached ADUs are generally limited to one story or a maximum height for accessory structures in the applicable district.
• Lot coverage: District-specific maximum lot coverage applies.

Always verify current standards with the Planning and Zoning Department.

Mississippi River Flood Zone Considerations

Cape Girardeau sits on bluffs above the Mississippi River, with the historic downtown area at a higher elevation. However, portions of the city in lower-lying river-adjacent areas are subject to Mississippi River flooding. The city has a floodwall that protects portions of the downtown and some riverfront areas, but properties outside the floodwall are potentially exposed to river flooding. Key points:

• Check FEMA's Flood Map Service Center (msc.fema.gov) for your property's current flood zone designation.
• Properties in FEMA Special Flood Hazard Areas must comply with city floodplain management ordinance requirements.
• The Mississippi River has experienced major flood events affecting Cape Girardeau (1993, 2011, 2019 among others).
• Levee and floodwall certification status can affect flood insurance requirements.

University Context — SEMO

Southeast Missouri State University (SEMO) is located in Cape Girardeau, and the surrounding neighborhoods have significant rental housing demand. If you intend to rent your ADU, confirm compliance with Cape Girardeau's rental housing licensing and inspection requirements with the city. Some areas near campus may have additional zoning considerations.

Historic Context

Cape Girardeau has historic neighborhoods and properties, including areas near the riverfront and the city's historic downtown. If your property is in or adjacent to a designated historic district, additional design review may apply to exterior ADU modifications.

Permit Process

1. Confirm zoning district: Check your property's zoning using the city's GIS or zoning map.
2. Verify flood zone status: Check FEMA's Flood Map Service Center; confirm floodwall coverage if applicable.
3. Review Code of Ordinances: Identify ADU standards for your district.
4. Pre-application consultation: Contact the Planning and Zoning Department with questions.
5. Prepare plans: Work with an architect or designer to prepare site plan, floor plans, and elevations.
6. Submit building permit application: File with the Building Division or Planning and Zoning Department.
7. Plan review: Staff reviews for zoning, building code, and floodplain compliance.
8. Permit issuance: Obtain permit before starting construction.
9. Inspections and Certificate of Occupancy: Complete required inspections; obtain CO before occupying.

Contact Information

City of Cape Girardeau Planning and Zoning Department 401 Independence Street, Cape Girardeau, MO 63703 Phone: (573) 339-6327 Website: cityofcapegirardeau.org/departments/planning-zoning

Disclaimer: Zoning regulations change frequently, and flood zone designations can change with FEMA map revisions. Always verify current ADU rules and flood zone status directly with the City of Cape Girardeau Planning and Zoning Department before beginning any project. This page is for informational purposes only and does not constitute legal or zoning advice.