Section R. 325.11114 - Ground level gravity storage tanksRule 1114.
(1) The bottom of a ground level gravity storage tank shall be above the highest groundwater level.(2) The bottom of a ground level gravity storage tank shall be located at least 1 foot above the 100-year flood elevation or the maximum recorded flood elevation, whichever is greater.(3) The site of a ground level gravity storage tank shall be graded to direct surface drainage away from the tank.Mich. Admin. Code R. 325.11114