25 Pa. Code § 78.58
For pits in existence on July 29, 1989, the operator may request approval for an alternate method of satisfying the requirements of § 78.57(c)(2)(iii) (relating to control, storage and disposal of production fluids), the angle of slope requirements of § 78.57(c)(2)(v) and the liner requirement of § 78.57(c)(2)(vi)-(viii) by affirmatively demonstrating to the Department's satisfaction, by the use of monitoring wells or other methods approved by the Department, that the pit is impermeable and that the method will provide protection equivalent or superior to that provided by § 78.57. The operator shall request approval under § 78.57(c)(1).
25 Pa. Code § 78.58
This section cited in 25 Pa. Code § 78.54 (relating to general requirements); 25 Pa. Code § 78.55 (relating to control and disposal planning); and 25 Pa. Code § 78.56 (relating to pits and tanks for temporary containment).