(b) Outer casing seal for gravel well industrial and irrigation wells.

1. (1)

   1. (A) Industrial wells shall be sealed with a concrete slab, grouted, or both.
   2. (B) Irrigation wells shall be sealed with a bentonite seal.
   3. (C) It is optional to use a slab for an irrigation well.

2. (2) Slabs.

   1. (A) Slabs must be of reinforced concrete and at least four inches (4”) thick and have a diameter sufficient to overlap the drill hole by two feet (2’).
   2. (B) The top of the slab shall be sloped to drain to all sides.
3. (3) Grout. Grout must be composed of sodium montmorillonite clay, also known as bentonite, cement, or a sodium montmorillonite (bentonite)-cement mixture and shall fill the annular opening between the casing and the drill hole in the upper ten feet (10’).
4. (4) Timing. If noted on the Report of Water Well Construction, a slab may be placed on nongrouted wells within one (1) year of the date of construction to allow for settling.

5. (5) Gravel refill pipes. Gravel refill pipes may be installed if they:

   1. (A) Terminate above the concrete slab surface; and
   2. (B) Are provided with watertight caps.

(c) Public notice. Each new industrial or irrigation well and each existing industrial or irrigation well when brought under the rules of Acts 1969, No. 641, shall have a:

1. (1) Weatherproof sign attached in a conspicuous location stating that "THIS WATER IS NOT FOR DRINKING PURPOSES"; or
2. (2) Suitable decal of weatherproof material.

(d) Casing, screen, and all material for industrial and irrigation wells of steel construction over four inches in diameter.

1. (1) The minimum wall thickness shall be 7 gauge, or three-sixteenths of one inch (0.1875”).
2. (2) All material used shall not allow sand or sediment to enter a well.
3. (3) Where there is an acid condition screen material may be stainless steel, plastic, bronze, or other material suitable for the water and ground formations in which the well has been completed.

(f) Artificial pack.

1. (1) Wells designed for placement of an artificial pack shall be provided with an adequate screen having openings based upon size of the gravel.
2. (2) The well shall be developed to ensure free entry of water without sediment.