For conversions of existing production wells which do not have surface casing completely covering the fresh water zone, further cementing is not required unless it is necessary to establish external mechanical integrity in accordance with Section 240.770.
For all conversions of existing production wells, cement shall extend to at least one hundred (100) feet above the injection interval or the bottom of the casing in an open hole completion.
Ill. Admin. Code tit. 62, § 240.720
Former Section recodified to Section 240.680; new Section adopted at 15 Ill. Reg. 15493, effective October 10, 1991