ADU rules in Dickinson

Dickinson allows one ADU per owner-occupied single-family lot, detached units included, by right in the AG Agricultural, RR Rural Residential (lots of two acres or more), R-2, R-3 and MH districts. ADUs are not allowed in R-1 Low-Density Residential, the city's main single-family district, or in mobile home parks. The R-1 exclusion was deliberate: the Planning and Zoning Commission recommended Ord. 1706 on 10-21-2020 only 'excluding R1 zoning' after residents objected, and the City Commission adopted it on that condition on 11-17-2020. A detached ADU may not sit in the front yard, must be smaller than the house's footprint (attached garage excluded), may cover no more than 10 percent of the lot, and must match the house's residential appearance. No detached ADU is available in the commercial districts, where 62-474(b) allows only attached or internal units.

An ADU may be inside the house (a basement or other internal unit) or attached to the house or to a detached accessory structure, in the same districts as detached units: AG, RR on lots of two acres or more, R-2, R-3 and MH, never R-1 and never in a mobile home park. Separately, 62-474(b) allows attached or internal ADUs in the LC, CC and GC commercial districts (not LI or GI) through administrative Planning Department approval; these are 300 to 700 sq ft, capped at two occupants, held under a temporary certificate of occupancy renewed every 12 months, and defined as an apartment for temporary use by an employee of the business. The West Villard and Downtown overlay districts also list ADUs among the uses allowed in single-family structures on commercially zoned lots.

Section 62-474(a)(5) sets a 400 sq ft minimum and a 900 sq ft maximum building area for ADUs in the AG and residential districts, internal and detached alike, on top of the district's area regulations and lot coverage limit. A detached ADU must be smaller than the primary dwelling's footprint (an attached garage does not count toward the footprint) and may not cover more than 10 percent of the lot area. The ADU section sets no height limit of its own; Note 12 to the district tables limits detached structures in residential districts to 15 feet or the height of the house, whichever is less, unless the structure is set back an extra two feet from the side and rear lines for each foot above that. Attached ADUs in the LC, CC and GC commercial districts must be 300 to 700 sq ft (garage excluded) and no more than 40 percent of the principal building. Any deviation from these standards requires a variance.

No ADU may be created, established or occupied unless the property owner lives in either the main house or the ADU on the same lot. 'Owner occupied' means full-time residency by the bona fide owner as shown on the county tax assessment rolls, and the rule is ongoing because it governs occupancy, not just the application. North Dakota has no statute preempting local owner-occupancy rules, and the Legislative Assembly cannot change that before its January 2027 session. The commercial-district ADUs in 62-474(b) carry no owner-occupancy rule but are limited to temporary occupancy by an employee of the business.

Section 62-474(a)(8) requires a single-family home with an ADU to provide at least two off-street spaces for the house and one for the ADU, three in total, and all parking must meet city rules. There is no transit, lot-size or conversion exemption. In the LC, CC and GC commercial districts, 62-474(b)(5) requires at least two off-street spaces for the ADU on top of those the principal building needs. North Dakota has no parking preemption.

Table 62-162-2 lists 'Accessory dwelling units residential' as P (permitted by right) in AG, RR, R-2, R-3 and MH, 'subject to approval in accordance with § 62-474(a)', so a compliant ADU needs a building permit and certificate of zoning compliance from the Building Official (62-58), utility-availability documentation (62-474(a)(11)) and its own 911 address, with no public hearing. When the City Commission adopted Ord. 1706 in November 2020, staff said ADUs 'would go through permitting as other structures do.' Section 62-474(a)(5) says a deviation from the ADU standards 'will require a variance as part of the special use permit', a stray phrase given the by-right listing; a deviation in practice means a Board of Adjustment variance under 62-61(3). Commercial-district ADUs are called a 'special exception' in 62-474(b) but are reviewed and approved administratively by the Planning Department. R-1 lots have no ADU route short of rezoning.

Section 62-474(a)(12) bars using an ADU for short-term rental, sets a 28-day minimum rental term, and bars selling or detaching the ADU by deed or condo plat; 62-474(a)(6) caps ADU occupancy at two people. Because the owner must live in one of the two units, the other may be rented long term. Dickinson has no short-term rental license and no STR use in its zoning code: a 2026 text amendment (ZTA-002-2026) to permit and license STRs in resident-owned homes cleared the Planning and Zoning Commission on 2-11-2026, but the City Commission voted to deny it as written on 2-17-2026, and staff had told the commission on 10-8-2025 that ADUs would not be eligible for STR use under that approach. Commercial-district ADUs are limited to temporary occupancy by an employee of the business and must be removed or disabled within two months after a qualifying occupant leaves.