43 U.S.C. § 1542

The Secretary shall determine the repayment capability of Indian lands within, under, or served by any unit of the project. Construction costs allocated to irrigation of Indian lands (including provision of water for incidental domestic and stock water uses) and within the repayment capability of such lands shall be subject to section 386a of title 25 , and such costs that are beyond repayment capability of such lands shall be nonreimbursable.