Section R. 325.12404 - Manhole covers and openingsRule 2404.
(1) Manhole covers and openings shall be constructed to allow reasonable access for cleaning purposes and to protect the sanitary quality of the water.(2) Manholes and other openings in the top of the tank shall be higher than the surrounding area and shall be designed to prevent drainage from entering the opening.Mich. Admin. Code R. 325.12404