24 CFR §1000.147

1. (a)Housing qualifies as affordable housing, provided that the family occupying the unit is low-income at the following times:
   1. (1)In the case of rental housing, at the time of the family's initial occupancy of such unit;
   2. (2)In the case of a contract to purchase existing housing, at the time of purchase;
   3. (3)In the case of a lease-purchase agreement for existing housing or for housing to be constructed, at the time the agreement is signed; and
   4. (4)In the case of a contract to purchase housing to be constructed, at the time the contract is signed.
2. (b)Families that are not low-income as described in this section may be eligible under § 1000.104 or § 1000.110.