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The Rise of Accessory Dwelling Units

Accessory dwelling units (ADU) are smaller housing single-family units attached or detached from a home. These can be placed over the garage, within the backyard, or as part of a basement (American Planning Association, 2021). According to Chapple, Wegmann, Mashhood, and Coleman (2017), ADUs have become increasingly popular in the Pacific Northwest of the United States and Canada. Homeowners enjoy the low cost of construction and the flexibility the units provide. These units can be used as an office, rental property, or families wanting a place to stay.

An ADU is typically a small unit and includes one bedroom and one bathroom. In North Dakota, these units were approved in 2016 by the Bismarck City Commission to be built. According to Eckroth (2016), the Bismarck City Commission strives to discourage urban sprawl and offer a more affordable type of housing. Homeowners who are interested in an ADU can apply for a special use permit. Some specifications need to be abided by if the ADU is going to be built. The ADU has to be between 300 and 800 square feet on a lot less than five acres in area. If the lot area is greater than 5 acres, the ADU can be built up to 1,200 square feet (Board of City Commissioners, 2018). The ADU must not be as big as the existing home and must only have one bedroom. Other states will vary with their regulations, so it is essential to check with your state’s updated requirements before considering building an ADU.

The average expense of an ADU is about $156,000 to build. The cost does vary depending on the city, construction labor, and materials. These costs do not include purchasing the land or ground parking structures (Chapple, Wegmann, Mashhood, & Coleman, 2017). However, these units cost less than new single-family homes on a separate lot. They can benefit individuals who want to live close to family or young adults just entering the workforce (U.S. Department of Housing and Urban Development, 2008).

ADUs can be an excellent option for individuals considering a short-term place to live, want to live in a smaller home, or would like to live nearby their family. These units can also provide a significant return investment and increase the resale of your property. An ADU is an affordable and sustainable option for individuals looking to build or rent. With the costs of homes increasing, an ADU can be a choice to address the issue.


American Planning Association. (2021). Accessory dwelling units. Retrieved from

Board of City Commissioners. (2018). City of Bismarck ordinance no. 6310. Community Development Department. Retrieved from

Chapple, K., Wegmann, J., Mashhood, F., & Coleman, R. (2017). Jumpstarting the market for accessory dwelling units: Lessons learned from Portland, Seattle, and Vancouver. UC Berkeley. Retrieved from

Eckroth, L. (2016, July 26). Bismarck oks new ‘granny flats’ code. The Bismarck Tribune. Retrieved from oks-new-granny-flats-code/article_c01c6146-7a74-5088-b119-257e547e33d4.html

U.S. Department of Housing and Urban Development. (2008). Accessory dwelling units: Case study. Retrieved from

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