Idaho Code § 50-1805A
Except where a landowner makes a timely written demand for delivery of water in accordance with the water right or water rights allocated and made appurtenant to his lands, water rights may be pooled for delivery purposes, but such pooling shall not be deemed a change in place of use and shall not require compliance with sections 42-108 or 42-222, Idaho Code. Failure of a landowner to make written demand for delivery of water in accordance with the water rights allocated and made appurtenant to his land, on or before March 1 of the applicable year, shall be deemed consent by that landowner to the pooling of water rights for delivery purposes as provided in this section. When water rights are pooled for delivery, the city shall adopt a uniform method of allocating the assessments and charges of the irrigation district against all lands for which water rights are thus pooled. The city shall furnish the district a certified list or map showing all lands for which water rights have been pooled and shall indicate that a uniform method of allocating assessments and charges has been established; and subsequent assessments and charges of the district against those lands shall be levied or made as if all such lands constituted a single parcel, but the assessments and charges of the district shall be allocated by the city proportionately and separately for each actual parcel of such lands, according to the list and apportionment of benefits made by the district for the applicable assessment or charge, and no lien shall attach to any parcel except for assessments or charges properly allocated to that parcel.
Idaho Code § 50-1805A