((a)) ** In general** Housing shall qualify for affordable housing for purposes of this subchapter only if—

((1)) each dwelling unit in the housing—

((A)) in the case of rental housing, is made available for occupancy only by a family that is a low-income family at the time of the initial occupancy of that family of that unit; and

((B)) in the case of housing for homeownership, is made available for purchase only by a family that is a low-income family at the time of purchase; and

((2)) each dwelling unit in the housing will remain affordable, according to binding commitments satisfactory to the Secretary, for—

((A)) the remaining useful life of the property (as determined by the Secretary) without regard to the term of the mortgage or to transfer of ownership; or

((B)) such other period as the Secretary determines is the longest feasible period of time consistent with sound economics and the purposes of this subchapter, except upon a foreclosure by a lender (or upon other transfer in lieu of foreclosure) if that action—

((i)) recognizes any contractual or legal rights of any public agency, nonprofit sponsor, or other person or entity to take an action that would—

((I)) avoid termination of low-income affordability, in the case of foreclosure; or

((II)) transfer ownership in lieu of foreclosure; and

((ii)) is not for the purpose of avoiding low-income affordability restrictions, as determined by the Secretary.

((b)) ** Exception** Notwithstanding subsection (a), housing assistance pursuant to shall be considered affordable housing for purposes of this subchapter.section 4228(a)(2)(B) of this title