Mich. Comp. Laws § 280.483 : DRAIN CODE OF 1956 —THE DRAIN CODE OF 1956 — CHAPTER 20. INTRACOUNTY DRAINS; PUBLIC CORPORATIONS — Certiorari; time; legal establishment of drain

Neither the final order of determination nor the final order of apportionment shall be subject to attack in any court, except by proceedings in certiorari brought within 20 days after the filing of such order in the office of the chairman of the board issuing the same. If no such proceeding shall be brought within the time above prescribed, the drain shall be deemed to have been legally established and the legality of the drain and the assessments therefor shall not thereafter be questioned in any suit at law or in equity, either on jurisdictional or nonjurisdictional grounds.