Idaho Code § 43-2520
Whenever any land against which there has been levied any special assessment by any district shall have been sold in part or subdivided, the board of that district shall have the power to order a segregation of the assessment.
Any person desiring to have such a special assessment against a tract of land segregated to apply to smaller parts thereof shall apply to the district which levied the assessment. If the board determines that a segregation should be made, it shall by resolution order the treasurer to make segregation on the original assessment roll of the local improvement district as directed in the resolution and in accordance with section 43-701, Idaho Code. The segregation shall be made as nearly as possible on the same basis as the original assessment was levied, and the total of the segregated parts of the assessment shall equal the assessment before segregation. The resolution shall describe the original tract, the amount and date of the original assessment, and shall define the boundaries of the divided parts and the amount of the assessment chargeable to each part. A certified copy of the resolution shall be filed with the county recorder. The board may require, as a condition to the order of segregation, that the person seeking the segregation pay the district the reasonable engineering and clerical costs incident to making the segregation. No segregation need be made if the board shall find that by such segregation the security of the lien for the assessment will be so jeopardized as to reduce the security for any outstanding local improvement district obligations payable from such assessment.
Idaho Code § 43-2520