1. Diameter of drill hole must be 3" larger than the outer diameter of the casing or coupling, whichever is greater. 2. Casing must extend a minimum of 20'. 3. Annular space that exists between hole and casing must be filled with bentonite grout or neat cement grout within a maximum of 10 feet of the top of the screen to finished ground surface. .

(Source: Amended at 37 Ill. Reg. 19676, effective November 25, 2013)