Upon the completion of plugging or replugging a well, the operator shall erect over the plugged well a permanent marker of concrete, metal, plastic or equally durable material. The marker must extend at least 4 feet above the ground surface and enough below the surface to make the marker permanent. Cement may be used to hold the marker in place provided the cement does not prevent inspection of the adequacy of the well plugging. The permit or registration number shall be stamped or cast or otherwise permanently affixed to the marker. In lieu of placing the marker above the ground surface, the marker may be buried below plow depth and shall contain enough metal to be detected at the surface by conventional metal detectors.
25 Pa. Code § 78.96
This section cited in 25 Pa. Code § 78.86 (relating to defective casing or cementing); 25 Pa. Code § 78.91 (relating to general provisions); and 25 Pa. Code § 78.407 (relating to plugging gas storage wells).