Idaho Code § 43-1825

The secretary of the district must, on or before the first day of February, deliver the assessment book or books containing the record of such separate operation and maintenance assessment to the treasurer of the district who shall, within ten (10) days, forward by mail to each landowner or entryman, at his last known post-office address as shown by the records of such district, a notice stating the amount assessed against his lands, and that said assessment is due and payable and will become delinquent at six o’clock p.m., on the first day of the following March and also the times and places when and at which assessments will be received.