26 CFR § 1.528-4 - Substantiality test.
(a) In general. In order for an organization to be considered a condominium management association or a residential real estate management association (and therefore in order for it to be considered a homeowners association), substantially all of its units, lots or buildings must be used by individuals for residences. For the purposes of applying paragraph (b) or (c) of this section, and organization which has attributes of both a condominium management association and a residential real estate management association shall be considered that association which, based on all the facts and circumstances, it more closely resembles. In addition, those paragraphs shall be applied based on conditions existing on the last day of the organization's taxable year.
(b) Condominium management associations. Substantially all of the units of a condominium management association will be considered as used by individuals for residences if at least 85% of the total square footage of all units within the project is used by individuals for residential purposes. If a completed unit has never been occupied, it will nonetheless be considered as used for residential purposes if, based on all the facts and circumstances, it appears to have been constructed for use as a residence. Similarly, a unit which is not occupied but which has been in the past will be considered as used for residential purposes if, based on all the facts and circumstances, it appears that it was constructed for use as a residence, and the last individual to occupy it did in fact use it as a residence. Units which are used for purposes auxiliary to residential use (such as laundry areas, swimming pools, tennis courts, storage rooms and areas used by maintenance personnel) shall be considered used for residential purposes.
(c) Residential real estate management associations. Substantially all of the lots or buildings of a residential real estate management association (including unimproved lots) will be considered as used by individuals as residences if at least 85% of the lots are zoned for residential purposes. Lots shall be treated as zoned for residential purposes even if under such zoning lots may be used for parking spaces, swimming pools, tennis courts, schools, fire stations, libraries, churches and other similar purposes which are auxiliary to residential use. However, commercial shopping areas (and their auxiliary parking areas) are not lots zoned for residential purposes.
(d) Exception. Notwithstanding any other provision of this section, a unit, or building will not be considerd used for residential purposes, if for more than one-half the days in the association's taxable year, such unit, or building is occupied by a person or series of persons, each of whom so occupies such unit, or building for less than 30 days.