Calaveras County Municipal Code Art. IV Construction

Any drilling fluids or foams used in boring a new well shall be free from contaminants and pollutants. Any water used in boring a new well shall be obtained from a potable water source.

(Ord. No. 2946, § 1, 5-6-2008).

A. The well driller, or the authorized agent thereof, shall ensure that all well drilling wastes, such as cuttings, foams, drilling mud, water or other fluids or solids, do not enter any drainage, tributary, stream, river, water way, flood plain or any body of water.

B. The well driller, or the authorized agent thereof, shall ensure that all well drilling wastes, such as cuttings, foams, drilling mud, water or other fluids or solids, are contained within the boundary of the property upon which the well is being drilled.

C. Well drilling muds shall be discharged to a sump with at least two feet of freeboard. Drilling muds may remain in the sump only if the well contractor demonstrates that the drilling muds are nontoxic. The sump area shall be restored to the pre-construction state within sixty days of completion or abandonment of the well.

(Ord. No. 2946, § 1, 5-6-2008).

A. Any well casing that is installed shall be of sufficient strength to withstand any forces or stresses imposed during installation and any forces or stresses incurred under normal operating conditions following installation. All well casing used shall be manufactured in accordance with and meet performance standards as established by the American Society for Testing and Materials (ASTM), the American Petroleum Institute (API) or the American Water Works Association (AWWA).

B. With the exception of piezometers, casings for new wells shall be no less than six inches in diameter, and boreholes below the bottom of the annular seal shall be no less than six inches in diameter.

C. An existing well may be deepened and re-lined with well casing that is less than six inches in diameter.

(Ord. No. 2946, § 1, 5-6-2008).

The director may grant a variance or an exemption, in consideration of any unusual circumstance whereby an unnecessary hardship would result from the application of the standard, and where the granting of such a variance or an exemption would neither cause nor create a hazardous condition or endanger public health and safety.

(Ord. No. 2946, § 1, 5-6-2008).

All glues, primers and solvents used with well casing shall be compatible and shall meet applicable ASTM standards.

(Ord. No. 2946, § 1, 5-6-2008).

A. If a temporary conductor casing is used to prevent caving during the drilling process or placement of the annular seal, the conductor casing shall be removed during installation of the annular seal.

B. If a conductor casing is to be left in place, the annular space between the conductor casing and the borehole wall shall be sealed, from the ground surface to the applicable depth or at least ten feet into an impervious, bedrock layer, whichever is deeper.

C. If a conductor casing is to be left in place, and the annular space between the conductor casing and the borehole wall cannot be sealed to the applicable depth, an annular seal shall be installed below the conductor casing and shall extend downward for the applicable depth or at least ten feet into an impervious, bedrock layer, whichever is deeper.

(Ord. No. 2946, § 1, 5-6-2008).

A. The well casing shall extend a minimum of twelve inches above the ground surface and a minimum of six inches above the concrete surface seal.

B. Casing shall be equipped with centering guides, where applicable, to ensure even thickness of the annular seal.

(Ord. No. 2946, § 1, 5-6-2008).

A. Perforated well casing shall be installed at a depth of no less than twenty feet below the ground surface.

B. The perforations shall be placed only in aquifers that underlie an impervious, bedrock layer and are neither contaminated nor polluted.

(Ord. No. 2946, § 1, 5-6-2008).

The annular space shall be sealed, to the proper depth, with cement grout or other approved material to prevent the intrusion of surface and shallow, subsurface contaminants and pollutants into the aquifer.

(Ord. No. 2946, § 1, 5-6-2008).

A. The annular seal shall have a minimum width or thickness of two inches.

B. The annular space shall be filled to the proper depth with cement grout, bentonite clay, either slurry, chips or pellets, or other sealing material approved by the director.

C. If a well is drilled through fill material, the annular space from the top of the fill material to the original ground surface shall be sealed with cement grout, bentonite clay, or other sealing material approved by the director. In addition, the annular space from the original ground surface (the native soil surface below the fill material) shall be sealed with cement grout, bentonite clay, or approved sealing material approved by the director, to the applicable depth or at least ten feet into an impervious, bedrock layer, whichever is deeper.

D. If the well location is approved within twenty-five feet of any permanent or seasonal water course, such as, but not limited to, a drainage, tributary, stream, river, water way, flood plain or any body of water, the annular seal must extend below the bed of the water way for the applicable depth or at least ten feet into an impervious, bedrock layer, whichever is deeper.

E. Any grouting material that is used to fill the annular space shall be applied in one continuous pour. Deviations from this process may be approved, by the director, on a site by site basis.

F. The minimum depth of the annular seal shall be:

Minimum Depth of Seal Below Ground Surface

* Below the bed of the water way.

G. The director, depending on site specific conditions or to mitigate potential contamination or pollution threats, may require the installation of an annular seal that is deeper than the minimum depths required above.

(Ord. No. 2946, § 1, 5-6-2008).

The annular space shall be sealed during drilling or as soon as practical thereafter. In no case shall the annular space be left open longer than fourteen days following the installation of the well casing.

(Ord. No. 2946, § 1, 5-6-2008).

Gravity installation of sealing material is prohibited unless the interval to be sealed is dry and is no deeper than thirty feet.

(Ord. No. 2946, § 1, 5-6-2008).

A. The following materials and mixtures are approved for use in sealing wells:

1. Neat cement: One sack (ninety-four lbs.) Portland cement to five to ten gallons of potable water;

2. Cement grout: Not more than two parts of sand by weight and one part of cement by weight to five to seven gallons of potable water;

3. Bentonite and bentonite sealing materials used in accordance with the specifications of the manufacturer or as approved by the director;

4. Quick setting cement, setting retardants, bentonite, or other additives, if used, may not exceed five percent of total volume. Hydrated lime may be used up to ten percent of the volume;

5. If more than four sacks of bentonite chips are required to remove water from the annular space, the remainder of the annular space shall be filled with approved sealing material;

6. If bentonite chips are used to fill an annular space, the chips shall be screened to remove fines then be dropped slowly into the well, but only through standing water, and

7. If the annular space of a well is to be sealed with hydrated, bentonite slurry, the annular space shall be filled by pumping the slurry through a tremie pipe from the top of the fill material to the ground surface.

B. Sealing materials, other than bentonite chips or pellets, shall not be poured through or into water.

(Ord. No. 2946, § 1, 5-6-2008).

Only licensed professionals holding an A (general engineering contractor), C-57 (water well drilling contractor), or C61/D21 (limited specialty-machinery and pumps) license, issued by the contractors state license board, may install and test well pumps.

(Ord. No. 2946, § 1, 5-6-2008).