Mich. Comp. Laws § 280.12
Except as provided in section 8, when a time is specified in this act in which the drain commissioner or a drainage board shall take a specified administrative action or a procedural step, the specification of time shall be considered directory and not mandatory and failure to take the action or step within the time specified shall not affect the legality and validity of a drain proceeding. Where the specification of time relates to the giving of notice, the filing of objections, the taking of an appeal, the commencement of an action in a court, the taking of an action or step in the assessment, levy, or collection of drain assessments, taxes or other charges, or to a requirement of due process, the specification of time shall be considered mandatory if so provided in this act.
MCL 280.12