Idaho Code § 50-1716
Upon passage of the assessment roll, the treasurer of the municipality shall mail a postcard or letter to each property owner assessed at his post office address if known, or if unknown, to the post office in the municipality where the improvement is being made, stating the total amount of his assessment, plus the substance of the terms of payments of the same as set out in the ordinance confirming the assessment roll.
An affidavit of the mailing of the notice shall be filed, before the date of delinquency, in the office of the treasurer in the file of the improvement district, but the failure of the treasurer to give any notice required by this section or to do any other act or thing required by this section, shall not affect the validity of the assessments or installments thereof due nor extend the time for payment, but shall subject the municipality to liability to a taxpayer for any damage sustained by the latter by reason of such failure.
Idaho Code § 50-1716