Idaho Code § 42-5113
The secretary of the board of directors shall be the assessor of the district, and on or before August 1 of each year shall prepare an assessment book containing a full and accurate list of all water users within the district.
At a regular meeting of the board between August 1 and November 1 of each year, the board of directors shall determine the amount necessary to be raised for payment of the annual payment on any and all indebtedness of the district for the following year. Money received in payment of such assessments shall be deposited in a separate fund to be known as the debt retirement fund. The board of directors may, in addition, determine the amount necessary to pay the expenses of making the assessment book, giving notice of assessments and making collections thereof and for the cost of contracts with state or federal agencies for monitoring programs, or evaluation of proposed contracts, and may levy assessments against the water users in the district sufficient to raise such amount. Money received in payment of such assessments shall be deposited in a separate fund to be known as the operating expense fund.
Each water user shall pay a proportionate share of the total of all amounts to be raised for the purposes aforementioned, which share shall be based on the ratio which the quantity of water such water user is authorized to appropriate under his water right or rights bears to the total quantity of water authorized for appropriation under the water rights of all water users in the district; provided, however, that the combined annual assessment against each water user shall not exceed one hundred dollars ($100) per second foot of water the water user is entitled to appropriate under his water right or rights, except, that the district may establish a ten dollar ($10.00) minimum assessment for any water user.
Idaho Code § 42-5113