36.21.666 ARTIFICIAL GRAVEL PACKED WELLS - GENERAL
(1) In gravel packed wells, the gravel mixture shall be placed around the screen so that bridging or size separation will not occur. The gravel pack shall be clean, chemically stable, and composed of reasonably uniform grains. All gravel and water used shall be disinfected in at least 50 ppm chlorine.
(2) Gravel packing shall be placed from the bottom of the screen upwards to 2 to 3 feet above the screen.