ADU Rules in Lisbon, North Dakota

Lisbon is the county seat of Ransom County in southeastern North Dakota, located on the Sheyenne River approximately 70 miles southwest of Fargo. The city has a population of roughly 2,100 and serves the surrounding agricultural region. Lisbon manages its own zoning and building regulations as an independent municipality.

No Statewide ADU Law — Local Zoning Controls

North Dakota has not passed statewide legislation preempting or standardizing local ADU regulations. All rules governing Accessory Dwelling Units (ADUs) in Lisbon are set exclusively by the City of Lisbon Zoning Ordinance. There is no state mandate requiring Lisbon to permit ADUs, and the city retains full authority to regulate or restrict them. Rules in Lisbon may differ substantially from those in larger North Dakota cities.

ADU Types That May Be Permitted

Depending on the zoning district, Lisbon may allow:

• Detached ADUs — freestanding backyard structures, carriage houses, or converted outbuildings
• Attached ADUs — living unit additions connected to the primary dwelling
• Garage conversions — repurposing an existing attached or detached garage into a habitable unit
• Basement or interior ADUs — self-contained apartments created within the footprint of the primary home

Whether any of these types is permitted on a given parcel depends on the zoning district designation, lot size, and applicable dimensional standards. Contact City Hall to confirm what is allowed for your property.

Typical Development Standards

Lisbon's zoning ordinance generally includes standards such as:

• Minimum lot size — a minimum lot area threshold must typically be met before an ADU is permitted
• Maximum ADU size — commonly capped in relation to the main home's gross floor area or an absolute limit (often 600–900 sq ft for smaller ND cities)
• Setbacks — rear and side yard setback requirements apply; detached ADUs must generally maintain a minimum separation from rear and side property lines (often 5 feet)
• Height — detached accessory structures are typically limited to one story or consistent with other accessory building standards in the zone
• Parking — at least one additional off-street parking space is commonly required for ADU residents
• Utility connections — ADUs must comply with city codes for water, sewer, and electrical service

Confirm all specific figures and requirements with the Lisbon Zoning Administrator before designing or permitting an ADU.

Sheyenne River Flood Zone Considerations

The Sheyenne River flows through the Lisbon area, and FEMA-mapped flood hazard areas exist in portions of the city. Properties within a Special Flood Hazard Area (SFHA) — typically mapped as Zone AE on FEMA Flood Insurance Rate Maps (FIRMs) — face additional requirements for any new construction, including ADUs:

• Finished floor elevations must meet or exceed the Base Flood Elevation (BFE)
• A floodplain development permit may be required in addition to a standard building permit
• Fill, grading, and foundation requirements are more stringent in flood zones
• Flood insurance may be required if the property carries a federally backed mortgage

Verify your parcel's flood zone status using the FEMA Flood Map Service Center at msc.fema.gov before proceeding. Properties not currently in a mapped SFHA but near the Sheyenne River are still encouraged to check current maps.

Extreme Cold Climate Requirements

Lisbon experiences harsh continental winters with temperatures that regularly fall to −20°F to −30°F. All ADU construction must comply with North Dakota building code requirements for cold climates:

• Frost depth: Foundations must penetrate well below the frost line — typically 5 to 6 feet in southeastern North Dakota
• Insulation: High-performance insulation in walls, roof, and below-grade assemblies is required
• Heating: The ADU must have an independently adequate heating system
• Snow loads: Structural design must account for regional snow accumulation

Permit Process

1. Contact City Hall to confirm the parcel's zoning district and ADU eligibility
2. Check flood zone status using FEMA maps; obtain a floodplain development permit if required
3. Obtain zoning approval or any required conditional use permit
4. Submit a building permit application with complete construction drawings
5. Schedule and pass all required inspections

Contact Information

City of Lisbon City Hall

• Website: lisbonnd.com
• Address: 205 Forest Street, Lisbon, ND 58054
• Phone: (701) 683-4161

Disclaimer: Zoning regulations change frequently. The information on this page is provided for general informational purposes only and may not reflect the most current rules. Always verify ADU requirements directly with the City of Lisbon and consult a licensed contractor or architect before beginning any project.