C.M.R. 06, 096, ch. 600, app 096-600-A
1. Monitoring wells must be a minimum of 2 inches in diameter.
2. The screened zone must extend at least 10 feet into the water table and at least 5 feet above the ground water surface, as determined at the time of installation; or when installed within a secondary containment liner, the base of the well screen must extend to within 6 inches of the low point of the liner.
3. The screened portion of a well outside a liner must be a minimum of 15 feet in length and must be factory slotted with a slot size of 0.010 inch.
4. Monitoring wells must be installed with a cap at the bottom of the slotted section of the well.
5. Monitoring wells must be constructed of flush joint, threaded schedule 40 PVC or other types of PVC which have equivalent or greater wall thicknesses.
6. Monitoring wells must be numbered such that all monitoring and testing results can be easily correlated to a specific monitoring well location.
7. All monitoring wells must be equipped with liquid-proof lockable caps.
8. Monitoring wells must be properly distinguished from oil piping using American Petroleum Institute recommended symbols.
9. The screened portion of the well must be surrounded by a porous medium (e.g., sand, gravel, or pea stone).
10. The outside of the well riser must be sealed to the wall of the boring using bentonite or a similar product to a depth of 1.5 feet below ground surface, or to 0.5 feet above the water table, whichever is shallower.
11. Monitoring wells which are located in traffic areas must be cut off at ground level, clearly marked, with a raised limited access cover in accordance with PEI RP100or properly protected from vehicles.
12. Any damaged monitoring well must be repaired, replaced, or properly abandoned as soon as possible after discovery of the damage.
13. Monitoring wells must be installed with a boring rig rather than a backhoe if they are not installed within a containment liner.
14. Unless required by the Department, monitoring wells within a diked area should be properly abandoned or completed in such a way to prevent oil from reaching ground water via the well should a spill occur within the diked area. Monitoring wells should be abandoned in accordance with the Guidance for Well and Boring Abandonment, Maine Department of Environmental Protection, Bureau of Remediation and Waste Management, Division of Technical Services.
15. All wells completed with a riser extending aboveground should be protected by a steel casing.
C.M.R. 06, 096, ch. 600, app 096-600-A