Accessory Dwelling Units in Colorado – Options For Community Associations to Regulate ADUs

September 23, 2020

In the midst of a record ten-year economic expansion, many cities across the country are scrambling for solutions to the perceived housing affordability crisis. One method of addressing housing affordability is to increase housing supply. Many municipalities either have recently changed, or are considering amending the zoning code to allow for construction of accessory dwelling units (“ADUs”). Depending on where you live, this could impact your community association. This article will briefly touch on tools Colorado community associations have at their disposal to attempt to control ADUs.

Please note that ADUs vary widely based on your municipality. The information contained in this article may not accurately reflect how your municipality governs ADUs.

What is an ADU?

Home - accessory dwelling unitsAn accessory dwelling unit is typically a dwelling that is “subordinate” to the primary dwelling.  Instead, the subordinate unit may take the form of a mother-in-law apartment, basement unit, or a garage or outbuilding that has been converted into a living space. This unit is substantially smaller than the primary dwelling and can be leased out separately.

Notably, the accessory unit must be a dwelling. Typically, this means the ADU must have independent living facilities. This includes a bathroom, kitchen, and some sort of bedroom/living space. If it lacks any of those three elements, it likely will not constitute an ADU.

Complete Prohibition of Accessory Dwelling Units

In almost all instances, even if a local municipality has permitted ADUs in various areas, including single-family communities, the governing documents of a community association are permitted to impose harsher restrictions than contained in the municipality’s code or ordinance. If your association is worried about the impact accessory dwelling units may have, it may be time to consider reasonable restrictions on ADUs. There are many ways that ADUs can be limited or controlled, such as the following:


One aspect of higher density is increased traffic and parking congestion. In communities where parking is already an issue, there may be even further issues with ADUs. Some ordinances require off street parking. If no such requirement in your municipality exists, this is a restriction your association could impose. As a small, subordinate dwelling, many newly constructed ADUs will lack garage parking. This will effectively prohibit accessory dwelling units in many areas where additional off-street parking is simply not available.


ADUs, when not used for immediate family, are often rented out as an extra source of income for primary homeowners. However, it may be wise to consider placing reasonable leasing restrictions on ADUs so that they do not become hotbeds for AirBnB or VRBO leasing. Unsurprisingly, these short term rentals are a commonly seen issue in community associations, and permitting excess housing in ADUs, without reasonable leasing restrictions could lead to serious issues.

Design Guidelines

Associations, where ADUs will be allowed, should also consider amending their design guidelines. This is to at least control the “look and feel” of the accessory dwelling units.  Just as with other features that associations may not completely prohibit—such as solar panels and xeriscaping—the association should still consider itself to have latitude in regulating an ADU’s design.

For example, if allowed by the governing declaration, an association’s design guidelines could potentially mandate certain setbacks, square footage limits, and other architectural elements of the ADU.  To minimize the visual impact of the ADUs, an association could also require by design guidelines. Guidelines could include that the ADU is not visible from the street, or other reasonable restrictions depending on the circumstances.


One common form of an ADU is a garage converted into a livable rental unit. Some governing documents prohibit garages from being used in this manner, while others do not. Associations should decide if they want to continue this prohibition or modify it to allow ADUs in these circumstances.

Noises and Nuisances

Some associations may desire to allow ADUs but also desire to minimize some of the effects of increased residential density, such as noise. Most governing documents have general provisions prohibiting excessive noise or lights, nuisances, offensive odors, or other noxious activities or annoyances. Associations with accessory dwelling units should consider tightening the definition of these “noxious activities” in well-drafted rules and regulations or a declaration amendment.

Discussion in Your Community

At a minimum, community associations should discuss the proposed ordinance at the Board level. Discussions should be with their attorneys and with any interested members.  Accessory dwelling units may be a great solution to help alleviate what is certainly a tight housing market. However, responsible community associations and managers should be aware of the many options available to them to either prohibit or control ADUs within their communities.

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