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Accessory Dwelling Units


Community Associations Institute (CAI)​ supports the right of community associations to determine if ADUs should be permitted. ​


CAI recognizes the need to provide more affordable housing opportunities in the United States. At the same time, CAI supports the rights of residential common-interest communities to reasonably regulate the development and placement of accessory dwelling units within their communities. In many parts of the United States the need for affordable housing is acute. Governmental regulatory bodies seeking to provide affordable housing opportunities must simultaneously recognize that need to ensure that roads, schools, availability of adequate parking, and other necessary services ensuring public safety, including those provided by the community association, are adequate to meet any additional burden resulting from an increase in the density of dwellings and population.

CAI supports legislation that recognizes the core principle of self-governance and equitable sharing of common property and the expenses necessary to operate the community association housing model, while simultaneously permitting, but not mandating, that affordable housing be constructed on single family lots.  In most states developers submit site plans for local approval, which relies on adequate infrastructure being constructed to support the project. Where adequate physical infrastructure does not exist, it must be supplemented without burdening the association and existing owners with additional expense. Legislation allowing the construction of affordable housing units within an existing common interest community must provide an association with equitable means to assess owners of new housing the additional expenses reasonably determined to result from the impact of occupants of accessory dwelling units within the common interest community without the need to amend declarations or bylaws.

As each residential common-interest community is unique, legislation should recognize the need for a particular community association to develop reasonable rules and regulations for accessory dwelling units consistent with that community's unique design, development, and operation. Such rules and regulations would necessarily include restrictions upon the design, materials used, size and location of accessory dwelling units. These rules and regulations may include, but are not limited to, prohibiting multiple dwelling units within one structure, setting reasonable density limits in communities, conversion of existing property improvements, vehicle and parking restrictions, the installation of additional amenities to support these additional dwellings, and the ability of a community association to establish equitable sharing of the incremental costs associated with the additional occupancy. CAI does not support legislation that prohibits community associations from adopting reasonable rules governing accessory dwelling units.

About the Community Association Housing Model

While community associations come in many forms and sizes, all associations share three basic characteristics: (1) membership in the association is mandatory and automatic for all property owners; (2) certain legal documents bind all owners to defined land-use requirements administered by the community association; and (3) all property owners pay mandatory lien-based assessments that fund association operations. Community associations are governed by a board of directors or trustees elected by their members. This board guides the association in providing governance and other critical services for the community usually funded by property taxes.


Accessory dwelling units come in many different forms across the country. An accessory dwelling unit may be a smaller, secondary, independent residential dwelling unit located on the same lot as a stand-alone (i.e., detached) single-family home in a community. Accessory dwelling units may also be known as granny flats, accessory apartments, in-law apartments, family apartments, room rentals, garage and/or basement conversions, patio enclosures, or secondary units and serve as a cost-effective alternative to increasing housing supply. These forms of housing continue to grow in popularity to keep up with the housing demand in residential neighborhoods, to provide affordable housing options, and to promote intergenerational living opportunities. In some localities the cost of housing has become unaffordable to existing residents, and those employed in a municipality such as firefighters and law enforcement officers, teachers, municipal workers, nurses, and other essential workers. This type of housing model also facilitates efficient use of existing housing supply and infrastructure, as well as improves homeowner cash flow. As the need for affordable housing options continues to grow, zoning policies are being revised to allow for the development of accessory dwelling units.

Historically, approvals granted to developers by local planning officials limit the amount of parking, open space, and other important amenities to support the original anticipated occupancy of the community, but not additional structures or occupants not envisioned when approvals were granted.

As a result, community associations experience practical issues when accessory dwelling units are added to existing common interest development communities that have rules with a valid purpose created to preserve the intended purpose and design characteristics of the community. Under certain circumstances, accessory dwelling units may create many unintended adverse consequences in a community, including but not limited to, parking issues, alteration of intended design, overcrowding of residents and structures, overtaxing common facilities and amenities, and increasing traffic congestion, all without a mechanism to reallocate assessment allocations to account for changes which would create an associated burden upon the community.


CAI supports legislation that recognizes the core principle of self-governance and co-ownership of common property and the community association housing model. CAI encourages policymakers to engage industry stakeholders, including community association homeowners, board members, volunteer leaders, and business partners, on this issue. Further, CAI believes crafting legislation and regulation should always take place in an open and transparent manner, providing the opportunity for comment by all interested parties.

Community Associations Institute (CAI) recognizes the need for affordable housing in the United States and supports the rights of residential common-interest communities to reasonably regulate the development of accessory dwelling units within their communities.

CAI opposes legislation that prohibits community associations from regulating the addition of accessory dwelling units without allowing for reasonable rules and restrictions.

CAI supports legislation that allows an association to develop reasonable rules and regulations requiring consistency with the common plan or scheme of the subdivision where accessory dwelling units are located within a community, including restrictions upon design, size, and location.

CAI supports providing a community association's board of directors the ability to use discretion in adopting uniform, reasonable individual assessment increases to offset the additional costs created by an accessory dwelling unit.

January 11, 2022 Approved by Government & Public Affairs Committee

February 9, 2022 Adopted by the Board of Trustees​