Idaho Code § 43-404A
If the reconstruction, rehabilitation or replacement of dams, structures or works determined necessary in accordance with section 43-401A, Idaho Code, involves a dam, structure or works which also provide water storage, diversion or delivery of water to water users or water user organizations for the use of said water on lands not within the boundaries of the district proposing the improvements, the district (hereinafter referred to as constructing district) may contract with such water users or water user organizations for payment by them, over a period of time not to exceed the period of any bonded indebtedness incurred by the constructing district to finance construction of the improvements, of a proportionate share of the cost of such improvements, including design, construction, land acquisition and other related costs, to include interest on the unpaid balance of said proportionate share of such water users or water user organization at a rate equal to the average rate of interest payable by the constructing district on any bonded indebtedness incurred by it in financing the improvements.
If the water user organization contracting for payment of a proportionate share of the costs of the improvements is an irrigation district (hereinafter referred to as contracting district) organized pursuant to title 43, Idaho Code, the board of directors of such district shall negotiate a proposed contract with the constructing district. Thereafter, the question of entering into the proposed contract shall be submitted to the electors of such contracting district in a manner substantially in conformance with the provisions of section 43-401, Idaho Code. If at least two-thirds (2/3) of the electors approve the execution of the contract, the board shall confirm the proceeding as provided in connection with a bond issue, and following confirmation, the board shall execute the contract and thereafter an annual assessment to provide revenue for payment of the obligation and interest thereon shall be levied and collected on lands within the contracting district in the manner provided for assessment for payment of bonds and interest thereon. The provisions of section 43-404, Idaho Code, shall be applicable to apportionment of benefits accruing under the terms of said contract.
If the water user organization contracting for payment of a proportionate share of the costs of improvements is an operating company entitled to a lien for maintenance charges under chapter 22, title 42, Idaho Code, it shall annually assess and collect the costs of meeting its obligations under the contract as a toll, assessment or charge under chapter 22, title 42, Idaho Code.
If the water user organization contracting for payment of a proportionate share of the costs of the improvements is a lateral ditch water user association organized and operating under chapter 13, title 42, Idaho Code, the annual cost of meeting the association's obligation under the contract shall be included in the assessment made under section 42-1303, Idaho Code, and chapter 13, title 42, Idaho Code, shall apply to the collection and disbursement of said assessment.
Idaho Code § 43-404A