Idaho Code § 43-2529
As soon as any assessment or installment thereof, of any local improvement district shall become delinquent, the treasurer shall, if such assessment be collected in one (1) payment, mark the same delinquent on the assessment roll, or if for an installment of an assessment, on the local improvement installment docket, and shall add to the amount shown on said assessment roll, or installment docket, a penalty of two percent (2%) thereon. Within ten (10) days thereafter the treasurer shall prepare and issue to the district in which such local improvement district is located, a delinquency certificate to the property included in each such delinquent assessment or installment, which certificate shall have the force and effect of a sale of said property to the district for the amount of the delinquent assessment or installment plus penalty, said certificate shall bear date as of the time such assessment or installment became delinquent and shall be for the amount thereof plus the penalty charged thereon. Such certificate shall contain: the description of the property to be sold; the name of the person assessed, if known, or if unknown, that fact; the amount of the assessment or installment, plus penalty thereon; the number of the assessment and the name of the local improvement district in which assessed; and the date when such certificate will go to deed and shall bear interest from date thereof at the rate of ten percent (10%) per annum. Such certificates shall be made in duplicate, bound together in books in numerical order and filed in the office of the treasurer; provided, that after one (1) such certificate has been issued no further delinquency certificate shall be issued for subsequent installments of the same assessment, except as hereinafter provided, and whenever any subsequent installment shall thereafter become delinquent the treasurer shall so mark the same in the installment docket and add the penalty thereto, as hereinbefore provided, and the same shall draw interest at the rate of ten percent (10%) per annum from date of delinquency until the end of the month in which it is paid.
Idaho Code § 43-2529