NAC445A.66905. Water wells: Seals and coatings.

     1. Except as otherwise provided in subsection 4 and NAC 445A.6691, a water well must have a sanitary seal consisting of neat cement, cement grout or concrete grout from a depth of not less than 50 feet below the surface to ground level, constructing the sanitary seal from bottom to top. If grout is used, contact must be ensured between the grout and the native formation. The sanitary seal must have a minimum thickness of 2 inches in the annular space of the well. The casing must be centered as nearly as practicable in the drill hole in such a manner as to allow the sanitary seal fully to surround the casing. Dry cement must not be placed in the annular space for use as a sanitary seal.

     2. Before any product may be used to coat, seal, patch or otherwise become attached to the surface of any material used to construct a water well in such a manner that the product will come into contact with drinking water, the product must be determined to be compatible with drinking water.

     3. If a permanent conductor casing is used in a water well, a watertight seal, consisting of concrete or a welded plate, must be placed at the surface level between the conductor casing and the production casing in such a manner as to prevent any pollutants or contaminants from entering the area of gravel pack.

     4. If a pitless adapter is used in the construction of a water well:

     (a) The sanitary seal must begin not more than 5 feet below the ground, be continuous and extend at least 50 feet; and

     (b) The exterior portion of the casing above the sanitary seal must be refilled to ground level with native material.

     5. Any pipe used to feed gravel through the sanitary seal of a water well or to provide access to the interior of a water well must be fitted with a watertight cap.

     (Added to NAC by Bd. of Health, eff. 2-20-97)