; and (3) provides assurances that the applicant will supplement assistance provided under this section with amounts from non-Federal sources for costs of the qualified affordable housing or infrastructure eligible under subsection (b) to be funded with assistance under this section, and the extent of such supplemental assistance to be provided. (e) Water and energy efficiency Not less than 10 percent of all amounts made available for assistance pursuant to this section shall be used only for eligible activities relating to water and energy efficiency and, at the Secretary’s discretion, other strategies to reduce emissions. (f) Qualified affordable housing For purposes of this section, the term qualified affordable housing means a housing development that— (1) is either— (A) funded in any part by assistance provided by the Department of Housing and Urban Development or the Rural Housing Service of the Department of Agriculture; or (B) includes a qualified low income building as such term is defined in section 42 of the Internal Revenue Code of 1986; or (2) consists of 5 or more dwelling units of which 20 percent or more are made available— (A) for rental only by a low-income family (as defined in section 3(b) of the United States Housing Act of 1937 ( 42 U.S.C. 1437a(b) )); (B) at a monthly rent amount that does not exceed 30 percent of the monthly adjusted income (as defined in such section 3(b)) of the tenant low-income family