Napa County Municipal Code Art. III Construction Specifications

All materials and workmanship shall be no less than the quality specified in this division. The requirements of these standards are minimal only, and any material or method determined by the director to give equivalent or better results may be required. Materials or methods not covered by these standards must meet the standards of the California Water Well Standards Bulletin 74-81 and the supplement thereto, bulletin 74-90, and must receive the written approval from the director prior to use. In the event of conflicting or contradictory requirements, the provisions of this division shall prevail. Except as otherwise contradictory, the California Water Well Standards Bulletin 74-81 and 74-90 and any subsequent supplements and revisions thereto are hereby incorporated by reference.

(Ord. 1159 § 1 (part), 1999)

A. All water wells, geothermal heat exchange wells, extraction wells for the purpose of permanent dewatering, and horizontal wells shall be located as follows:

Minimum Distances

1. Minimum distance may be reduced if conditions are met for Class 1B or Class II wells as listed in Section 13.12.270. Every effort shall be made to install the well in a location with the greatest possible setback distance.

2. Shall be fifty feet if sewer not constructed of approved building sewer materials.

As determined by the director, special setback distances may be required when the above wells are located near the following: regulated or unregulated underground fuel or storage tanks, contaminated sites, sanitary landfills and large scale animal or fowl operations.

B. Monitoring and cathodic protection wells, and exploratory borings shall maintain setbacks from potential sources of contamination as approved by the director. Such setbacks shall be dependent on the source of contamination, the depth of the monitoring or cathodic protection well, the depth and type of the annular seal, the formations which are penetrated, and the proposed usage.

(Ord. 1159 § 1 (part), 1999)

(Ord. No. 1374, § 21, 9-11-2012)

Editor's note— Ord. No. 1374, § 22, adopted Sept. 11, 2012, repealed § 13.12.350, which pertained to locations—exemptions and derived from Ord. No. 1159, § 1 (part), adopted 1999.

At all times during the progress of the work, or whenever there is an interruption in work on a well, the well shall be protected to prevent ground water contamination.

(Ord. 1159 § 1 (part), 1999)

A. All materials used for well casings shall be approved by the director and shall be structurally capable to perform the functions for which it is designed; i.e., to maintain the hole by preventing its walls from collapsing, to provide a channel for conveyance of the water, and to provide a measure of protection of the quality of the water pumped.

B. All casings shall be placed with sufficient care to avoid damage to casing sections or joints.

C. The casing shall extend at least eight inches above the ground surface, and at least two inches above the surface of any surrounding concrete slab, or as determined by the director.

(Ord. 1159 § 1 (part), 1999)

A. The annular space of Class IA wells shall be filled with acceptable sealant having a minimum thickness of two inches.

B. The sealing material shall consist of neat cement, sand-cement grout, bentonite clay, concrete or a mixture of such approved by the director. Used drillers' mud, cuttings or chips from drilling shall not be used as sealing material.

C. The sealing material shall extend from two inches above the ground surface to at least twenty feet below the ground surface, or at least two feet into impervious soil, whichever is the greater, except in the case of shallow water wells where no water-bearing stratum is encountered below twenty feet, the seal shall extend to a minimum depth of ten feet, and except for water wells which will serve a public water system, the seal shall extend to a minimum depth of fifty feet or two feet into impervious soil, whichever is greater. If bentonite clay is used, the uppermost three feet of the annular space must be neat cement, sand-cement grout, or concrete and shall be placed only after the bentonite has had sufficient time to settle. The requirements of this subsection do not apply to monitoring wells, cathodic protection wells and exploratory holes.

D. For monitoring wells, cathodic protection wells and exploratory holes, refer to Bulletin 74-90 for grouting requirements.

E. The grout shall be applied in one continuous process either by pressure or by gravity in such a manner as to exclude surface and other undesirable water from the well. Sealing material shall be placed by methods (such as the use of a tremie pipe or equivalent) that prevent bridging or dilution of the sealing material or separation of sand or aggregate from the sealing material. Annular sealing materials shall not be installed by freefall unless the interval to be sealed is dry and no deeper than thirty feet below the ground surface.

F. Prior to grouting the annular space, a bentonite clay seal consisting of pellets or other approved material may be placed at the bottom of the annular space.

(Ord. 1159 § 1 (part), 1999)

Access openings into the well casing for air release, disinfection and any other purpose necessary for maintenance and operation of the well are permitted, but must have a watertight seal.

(Ord. 1159 § 1 (part), 1999)

A. Well pits or below-ground discharge pipes may be permitted only when determined to be absolutely necessary by the director. Where the well casing terminates in a pit below the ground surface, the pit shall be constructed of monolithic, reinforced concrete, watertight in all respects. The top of such pit shall be covered with a concrete slab or equal material, or with a housing of satisfactory construction. The casing shall extend at least eight inches above the pit floor. The well pit shall be so constructed and protected so that flood, rain or surface waters cannot enter the pit. Additional requirements may be imposed where it is determined necessary by the director.

B. The pit shall be provided with a drainage sump and an automatic sump pump and audio type alarm (or, if topography permits, a "free" discharge protected against entrance of rodents, insects or flooding). The discharge from the sump pump shall not be connected to any sewer or pipe drain. Pits shall have easy access for proper operation, maintenance and inspection of the equipment, and shall have a locked hatch. Doorways or hatches shall at all times effectively keep water out of the pit.

(Ord. 1159 § 1 (part), 1999)

Newly constructed or repaired water wells shall be adequately treated in such a manner as to disinfect all parts of the well before or as the pump is set, with chlorine or an equal disinfecting chemical, to a strength of at least fifty parts per million of available chlorine, but not more than two-hundred parts per million, and held for at least eight hours, after which time the well shall be pumped to reduce the disinfecting chemical to a safe level.

(Ord. 1159 § 1 (part), 1999)

All pumps shall be installed so as to prevent contamination of the ground water supply by surface water or other contaminants. The pump shall be mounted through a sanitary well seal. There shall be an access opening for introduction of chlorine into the well and gravel pack.

(Ord. 1159 § 1 (part), 1999)

Upon completion of a well, the driller shall be responsible for the placing of a sanitary well seal, or if the pump is not installed immediately, a watertight and tamper-proof well cover shall be installed. The driller shall submit a report of completion within the time frame required by state law, made out in detail on the State Department of Water Resources reporting form to the director.

(Ord. 1159 § 1 (part), 1999)

A. No person shall install or maintain a well in any manner that will result in the pollution or contamination of the ground water, or which allows the entrance of surface waters into the ground water.

B. If evidence is presented to the satisfaction of the director that any existing well is polluting or contaminating the ground water, the director shall require that such well be destroyed in accordance with the provisions of this division, or repairs be made to such well to eliminate the pollution or contamination or the entrance of surface water into the ground water.

C. At a minimum, all water wells must be provided with a sanitary well seal. In circumstances where chemicals or other deleterious materials are injected into the water system, as a minimum an approved reduced pressure principle device or an approved air gap must also be provided at the well head.

D. In the case of a flowing artesian well, the well head shall be sealed and vented to prevent the continuous discharge of well water on to the surface of the ground.

(Ord. 1159 § 1 (part), 1999)

A. In no case shall a reconstruction permit be issued for a water well where a sewage disposal system is located less than fifty feet away. For additional information regarding this matter, refer to Section 13.12.270(C) for Class II wells.

B. If a water well is located greater than one hundred feet to a sewage disposal system, a reconstruction permit may be issued provided all efforts are made to meet the construction requirements of a Class IA well. If a well is located between fifty and one hundred feet from a sewage disposal system, a reconstruction permit may be issued if all efforts are made to meet the construction requirements for a Class IB well.

(Ord. 1159 § 1 (part), 1999)