Section R12-15-811. Minimum Well Construction Requirements

A.      Well casing

1.        Casing shall be of a sufficient strength and wall thickness to hold the borehole open and survive any necessary grouting. A person shall use only steel or thermoplastic casing in the construction of a well, unless the person has received a variance from the Director pursuant to R12- 15-820. The well casing or an extension of the casing shall extend a minimum of one foot above ground level. When installing a pitless adaptor, the casing may be ter- minated below ground level for aesthetic reasons or freeze protection purposes. Casing made of, or which has been exposed to, hazardous or potentially harmful materi- als, such as asbestos, shall not be used.

2.        All well casing joints or overlaps shall be made water- tight to prevent the degradation of the water supply by the migration of inferior quality water. Except as provided in subsection (H) of this rule, any openings in the casing that will be above the water level in the well, such as bar holes, cracks or perforations, shall be completely plugged or sealed.

3.        Thermoplastic casing shall be installed only in an over sized drillhole without driving. Thermoplastic casing shall conform with American Society for Testing and Materials Standard Specification F480-89 (1989), which is incorporated herein by reference and is on file with the Office of the Secretary of State. Rivets or screws used in the casing joints shall not penetrate the inside of the cas- ing.

4.        Steel casing shall be new or in like-new condition, free from pits or breaks, and shall conform with American Society for Testing and Materials Standard Specification A53-89a (1989), A139-89b (1989) or A312/A312M-89a (1989), whichever is applicable, all of which are incorpo- rated herein by reference and are on file with the Office of the Secretary of State.

5.        Copies of The American Society for Testing and Materi- als standard specifications referred to in subsections (3) and (4) above may be obtained with these rules at the Office of the Secretary of State of the State of Arizona, State Capitol, West Wing, Phoenix, Arizona 85007; from the Department of Water Resources, 3550 N. Central Avenue, Phoenix, AZ 85012; and from the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. This rule does not include any later amendments or editions of those stan- dard specifications.

B.       Surface seal

1.        Except as provided in subsections (2) and (4) of this sub- section, and R12-15-817(B)(1), all wells shall be con- structed with a surface seal as herein provided. The seal shall consist of steel casing, one foot of which shall extend above ground level, and cement grout placed in one continuous application from the bottom of the zone to be grouted to the land surface. If a pitless adaptor is uti- lized, the cement grout may terminate at the bottom of the pitless adaptor. The minimum length of the steel casing shall be 20 feet. The minimum annular space between the casing and the borehole for placement of grout shall be one and one-half inches. Curing additives, such as cal- cium chloride, shall not exceed ten percent of the total volume of grout. Bentonite as an additive shall not exceed five percent of the total volume. The minimum length of the surface seal shall be 20 feet. Any annular space between the outer casing and an inner casing shall be completely sealed to prevent contamination of the well.

2.        All hand-dug wells shall be constructed with a watertight curbing extending, at a minimum, from one foot above the natural ground level to the static water level, or into the confining formation if the aquifer is artesian. The curbing shall consist of poured cement grout or casing surrounded by cement grout. Concrete block with cement grout and rock with cement grout may also be used. The poured cement grout shall not be less than six inches thick. If casing is to be used, the minimum annular space between the casing and the borehole shall be three inches. Hand-dug wells shall be sealed at the surface with a watertight, tamper-resistant cover to prevent contami- nants from entering the well.

3.        All wells constructed by jetting or driving shall have cement grout placed in the annular space to a minimum depth of six feet. The minimum annular space between the casing and the borehole for placement of the grout shall be one and one-half inches.

4.        All horizontal wells, to prevent leakage, shall be con- structed with a surface seal consisting of steel casing and

cement grout extending a minimum of ten feet into the land surface.

C.      Access port. Every well with casing four inches in diameter or larger shall be equipped with a functional watertight access port with a minimum diameter of one-half inch so that the water level or pressure head in the well can be monitored at all times.

D.      Gravel packed wells

1.        If a gravel pack has been installed, the annular space between the outer casing and the inner casing shall be sealed, either by welding a cap at the top or by filling with cement grout from the bottom of the outer casing to the surface.

2.        If a gravel tube is installed, it shall be sealed with a cap.

E.       Vents. All vents installed in the well casing shall open down- ward and be screened to prevent the entrance of foreign mate- rial.

F.       Removal of drilling materials

1.        In constructing a water well, the well driller shall take all reasonable precautions to protect the producing aquifer from contamination by drilling materials. Upon comple- tion of the well, the well driller shall remove all foreign substances and materials introduced into the aquifer or aquifers during well construction. For purposes of this subsection, “substances and materials” means all drilling fluids, filter cake, lost circulation materials, and any other organic or inorganic substances.

2.        Materials known to present a health hazard, such as chrome-based mud thinners, asbestos products, and petroleum-based fluids, shall not be used as construction, seal or fill materials or drilling fluids.

3.        Drilling fluids and cuttings shall be contained in a manner which prevents discharge into any surface water.

G.      Repair of existing wells

1.        If, in the repair of a well, the old casing is withdrawn, the well shall be recased in conformance with these rules.

2.        If an inner casing is installed to prevent leakage of unde- sirable water into a well, the annular space between the casings shall be completely sealed by packers, casing swedging, pressure grouting or other methods which will prevent the movement of water between the casings.

H.      Monitor wells

1.        A monitor well may be screened up to ten feet above the highest seasonal static water level of record for the pur- pose of monitoring contaminants.

2.        A monitor well shall be identified as such on the vault cover or at the top of the steel casing. Identification infor- mation shall include the well registration number.

I.        Completion at the surface. In areas of traffic or public rights- of-way, wells may be constructed below the land surface in a vault. All other requirements in this Article shall apply.

Historical Note

Adopted effective March 5, 1984 (Supp. 84-2). Amended

effective June 18, 1990 (Supp. 90-2). The reference to R12-14-817(B)(1) in subsection (B)(1) corrected to read R12-15-817(B)(1) (Supp. 93-1). Amended by final rulemaking at 11 A.A.R. 5395, effective February 4, 2006

(Supp. 05-4).