Section R. 325.11115 - Hydropneumatic storage tanksRule 1115.
(1) For type I and type IIa public water supplies, a hydropneumatic tank shall be located above the established ground surface and installed in a wellhouse, except it shall be acceptable to expose 1 end of the hydropneumatic tank and the controls in a wellhouse and mound earth cover material over the remainder of the tank.(2) For type IIb and type III public water supplies, a hydropneumatic tank may be partially buried if controls are located in an approved basement or in a room or pit drained by gravity to the ground surface. A totally buried hydropneumatic tank may be used if manufactured and installed as approved by the department.Mich. Admin. Code R. 325.11115