ADU laws in North Dakota

In plain words

North Dakota does not have a statewide ADU law. An accessory dwelling unit (ADU) is a small second home on the same lot as a house. It could be a basement apartment, an addition, or a backyard cottage. In North Dakota, each city, county or township decides whether ADUs are allowed. They do this through zoning, which means the local rules about what you can build where. No ADU bill came up in the 2023 or 2025 sessions or in the two short special sessions held in 2026. The Legislature only meets in regular session every other year, and the next one starts in January 2027. Local rules differ a lot. Bismarck allows ADUs inside a home or in a separate building, with limits on size and parking. Its new zoning code took effect on October 1, 2026. It is not clear whether Bismarck still requires the owner to live on the property. That kind of rule is called owner occupancy, so ask the city. Grand Forks does not allow ADUs, and its city council voted in 2024 not to study changing that. Fargo is rewriting its zoning code, and the new rules were still a draft in fall 2026. Before you plan anything, call your local zoning office. You may be able to build an ADU if your local rules and your property allow it.

The rules at a glance

What to do next

1. Call your city planning office, or the county or township zoning office if you live outside city limits, and ask whether ADUs are allowed in your zone.
2. Ask what approval is needed (building permit only, or a conditional use permit or variance with a hearing) and what it costs.
3. Write down local limits on size, height, setbacks (how far a building must sit from property lines), parking and whether the owner must live on site.
4. Plan for the building code: a detached ADU usually needs a full frost-depth foundation, and on a well or septic system you need enough capacity for a second unit.
5. Check your deed and any HOA or subdivision covenants, which can ban a second unit even where zoning allows one.
6. If you are in Fargo, follow the Fargo LDC 2026 rewrite at fargoldc.org, since the adopted code may change what is allowed.

What your town still decides

North Dakota has no state law about ADUs. State statutes say cities (N.D.C.C. 40-47-01) and counties (N.D.C.C. 11-33-01) 'may' zone, and neither chapter mentions accessory dwelling units, so each city, county or township decides. The results differ sharply between the largest cities. Bismarck adopted a new Land Development Code on May 26, 2026 that took effect October 1, 2026; its ADU section allows one ADU inside or beside a single-family or two-family home, and the city's guide says ADUs are allowed by right in every residential district with only a building permit. Whether Bismarck still requires the owner to live on site is unclear: the old code (in force through September 30, 2026) did, the new code's ADU section does not mention it, and the city's September 2026 guide says a permit ends if the property stops being owner-occupied. Grand Forks does not allow ADUs, and in April 2024 its city council voted 5-1 not to study changing that. Fargo's current Land Development Code does not use the term 'accessory dwelling' (a 2017 city task force called it silent on extra units), and a full rewrite (Fargo LDC 2026) was out as a public review draft in August 2026 but not yet adopted. A review of every bill title from the 2023 and 2025 regular sessions and the January and September 2026 special sessions found no ADU bill. North Dakota's Legislature holds regular sessions in odd-numbered years, so the next regular chance for a statewide ADU bill is the session that starts in January 2027.

Examples of local rules

• Bismarck: Bismarck's new Land Development Code (adopted May 26, 2026, effective October 1, 2026) covers ADUs in Section 14-10-07.3. Owners of single-family or two-family homes may add one ADU inside the home or in a separate building. The city's guide says this is allowed by right in any residential district: no public hearing, just a building permit. Detached ADUs must be 300 to 800 sq ft (up to 1,200 sq ft on lots over 5 acres) and no taller than 25 feet; internal ADUs can be up to 40% of the home. One extra off-street parking space is required, city water and sewer must be connected where available, and the unit must meet the full residential building code. Owner occupancy is unclear: the guide says an ADU may be rented, but also that the permit ends if the property is no longer owner-occupied, while the new code's ADU section has no owner rule. The old code required the owner to live in one unit more than six months a year. Source
• Grand Forks: ADUs are not allowed; the most a residential lot can hold is two units (a duplex) in R-2 districts. On April 22, 2024 the City Council voted 5-1 not to pursue zoning changes to allow ADUs, even though the city's land use plan recommends them. Source
• Fargo: Zoning is in the Land Development Code (Chapter 20 of the Municipal Code). An exact-phrase search of the current code (September 10, 2026 version) finds no 'accessory dwelling' language, and a 2017 city task force white paper said the code was silent on extra dwelling units accessory to a single-family house. Fargo is rewriting the whole code (Fargo LDC 2026); a public review draft came out on August 14, 2026, but the City Commission has not adopted it, so the current code still applies. Ask Planning and Development before planning an ADU. Source

What we’re still confirming

• Bismarck's new code has no owner-occupancy rule, but the city's ADU guide says a permit ends if the owner stops living there; confirm with Bismarck Planning.
• Fargo released a draft land development code in August 2026; check what it proposes for ADUs.

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.