020-12 Wyo. Code R. § 12-9

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Current through April 27, 2019

Section 12-9 - Source Development

(a) Surface water.

(i) Structures.
- (A) Design of reservoir or river intake structures.
  - (I) Facilities for withdrawal of water from more than one level shall be provided in impoundments if the maximum water depth at the intake is greater than 20 feet (6.1 m). All ports or intake gates shall be located above the bottom of the stream, lake, or impoundment. The lowest intake point shall be located at sufficient depth to be kept submerged at low water levels.
  - (II) Where water temperatures are 34° F (1° C) or less, the velocity of flow into the intake structure shall not exceed 0.5 feet per second (. 152 m/s). Where intakes are located in shady reaches of a stream, facilities shall be available to diffuse air into the flow stream at a point in front of the intake pipe.
  - (III) Inspection manholes shall be located a maximum of every 1,000 feet (304.8 m) for pipe sizes 24 inches (0.61 m) and larger. Where pipelines operate by gravity and the hydraulic gradeline is below the ground surface, concrete manholes may be used. Where the pipeline is pressurized or the hydraulic gradeline is above ground, bolted and gasketed access ways shall be used.
  - (IV) Devices shall be provided to minimize entry of fish and debris from the intake structure.
- (B) Offstream reservoir. Offstream reservoirs shall be constructed to assure that:
  - (I) Water quality is protected by controlling runoff into the reservoir.
  - (II) Dikes are structurally sound and protected against wave action and erosion.

(ii) Impoundments and reservoirs. The site of any impoundment or reservoir shall be cleared of all brush, trees, and other vegetation to the high water elevation.

(iii) Raw water supply piping. No customer service connection shall be provided from the raw water transmission line to the treatment plant, unless there are provisions to treat the water to meet these standards, or the sole purpose of the service is for irrigation or agricultural water use.

(b) Groundwater.

(i) Number and capacity. The total developed groundwater source, along with other water sources, shall provide a combined capacity that shall equal or exceed the design maximum daily demand. A minimum of 2 wells, or 1 well and finished water storage equal to twice the maximum daily demand shall be provided. Where 2 wells are provided, the sources shall be capable of equaling or exceeding the design average daily demand with the largest producing well out of service.

(A) General considerations.
- (I) Every well shall be protected from and remain operational during the 100-year flood or the largest flood of record, whichever is greater.
- (II) All wells shall be disinfected after construction, repair, or when work is done on the pump, before the well is placed in service. Disinfection procedures shall be those specified in AWWA A-100 for disinfection of wells.

(B) Relation to sources of pollution. Every well shall be located further from any of the sources of pollution listed below. The isolation distances listed below apply when domestic wastewater is the only wastewater present.

(I) If the domestic sewage flow is less than 2,000 gallons per day (7,560 L/day), the following minimum isolation distance shall be maintained:

Source of Domestic Wastewater	Minimum Distance to Well
Sewer	50 feet ( 15.2 m)
Septic tank	50 feet (15.2 m)
Disposal field	100 feet (30.5 m)
Seepage pit	100 feet (30.5 m)
Cesspool	100 feet (30.5 m)

(II) If the domestic sewage flow is greater than 2,000 gpd (7,560 L/day) but less than 10,000 gpd (37,800 L/day), the following minimum isolation distances shall be maintained:

Source of Domestic Wastewater	Minimum Distance to Well
Sewer	50 feet (15.2 m)
Septic tank	50 feet (15.2 m)
Disposal field	200 feet (61 m)
Seepage pit	200 feet (61 m)
Cesspool	200 feet (61 m)

(III) For systems larger than 10,000 gallons per day (37,800 L/day), the isolation distance shall be determined by a hydrogeological study, in accordance with the requirements of Section 15 of Chapter 3 Water Quality Rules and Regulations, but shall not be less than those listed above.

(IV) For wastewaters other than domestic wastewater, the isolation distance required shall be determined by a hydrogeological study, in accordance with the requirements of Section 15 of Chapter 3 Water Quality Rules and Regulations.

(C) Relation to buildings.
- (I) When a well is adjacent to the building, the well shall be located so that the centerline, extended vertically, will clear any projection from the building by not less than 3 feet (0.91 m), and will clear any power line by not less than 10 feet (3.05 m).
- (II) When a well is to be located inside a building, the top of the casing and any other well opening shall not terminate in the basement of the building, or in any pit or space that is below natural ground surface unless the well is completed with a properly protected submersible pump. Wells located in a structure must be accessible to pull the casing or the pump. The structure shall have overhead access.

(D) Relation to property lines. Every well shall be located at least 10 feet (3.05 m) from any property line.

(ii) Testing and records.
- (A) Yield and drawdown tests. Yield and drawdown tests shall be performed on every production well after construction or subsequent treatment and prior to placement of the permanent pump. The test methods shall be clearly indicated in the specifications. The test pump capacity, at maximum anticipated drawdown, shall be at least 1.5 times the design rate anticipated. The test shall provide for continuous pumping for at least 24 hours or until stabilized drawdown has continued for at least 6 hours when test pumped at 1.5 times the design pumping rate.
- (B) Plumbness and alignment requirements. Every well shall be tested for plumbness and alignment in accordance with AWWA A-100. The test method and allowable tolerance shall be stated in the specifications.

(iii) Well construction.
- (A) Protection during construction. During any well construction or modification, the well and surrounding area must be adequately protected to prevent any groundwater contamination. Surface water must be diverted away from the construction area.
- (B) Well types and construction methods.
  - (I) Dug wells. Dug wells shall be used only where geological conditions preclude the possibility of developing an acceptable drilled well.
    
    (1.) Every dug well, other than the buried slab type, shall be constructed with a surface curbing of concrete, brick, tile or metal, extending from the aquifer to above the ground surface. Concrete grout, at least 6 inches (0.15 m) thick, shall be placed between the excavated hole and the curbing for a minimum depth of 10 feet (3.05 m) below original or final ground elevation, whichever is lower, or to the bottom of the hole, if it is less than 10 feet (3.05 m).
    
    (2.) The well lining in the producing zone shall readily admit water, and shall be structurally sound to withstand external pressures.
    
    (3.) The well cover or platform shall be reinforced concrete with a minimum thickness of 4 inches (10 cm). The top of the platform shall be sloped to drain to all sides. The platform shall rest on and overlap the well curbing by at least 2 inches (5 cm), or it may be cast with the curbing or the concrete grout. Adequately sized pipe sleeve(s) shall be cast in place in the platform to accommodate the type of pump, pump piping or wiring proposed for the well. Pump discharge piping shall not be placed through the well casing or wall.
    
    (4.) A buried slab type of construction may be used if the dug well is greater than 10 feet (3.05 m) deep. The well lining shall be terminated a minimum of 10 feet (3.05 m) below the original or final ground elevation, whichever is lower. A steel-reinforced concrete slab or platform, at least 4 inches (10 cm) thick, shall rest on and overlap the lining. A standard unperforated well casing shall extend from the concrete slab to at least 12 inches (30 cm) above the original or final ground surface, whichever is higher. This casing shall be firmly imbedded in the slab or connected to a pipe cast in the slab to ensure that the connection is watertight. The excavation above the slab shall be backfilled with a bentonite slurry or clean earth thoroughly tamped to minimize settling.
  - (II) Drilled, driven, jetted, or bored wells.
    
    (1.) A drilled well may be constructed through an existing dug well provided that an unperforated casing extends to at least 12 inches (30 cm) above the original ground or final surface, whichever is higher. A seal of concrete, at least 2 feet (0.61 m) thick, shall be placed in the bottom of the dug well to prevent the direct movement of water from the dug well into the drilled well. The original dug well shall be adequately protected from contamination as described above.
    
    (2.) Every drilled, driven, jetted, or bored well shall have an unperforated casing that extends from a minimum of 12 inches (30 cm) above ground surface to at least 10 feet (3.05 m) below ground surface. In unconsolidated formations, this casing shall extend to the water table or below. In consolidated formations, the casing may be terminated in rock or watertight clay above the water table.
  - (III) Sand or gravel wells. If clay or hard pan is encountered above the waterbearing formation, the permanent casing and grout shall extend through such materials. If a sand or gravel aquifer is overlaid only by permeable soils, the permanent casing and grout shall extend to at least 20 feet (6.1 m) below original or final ground elevation, whichever is lower. If a temporary outer casing is used, it shall be completely withdrawn as grout is applied.
  - (IV) Gravel pack wells. The diameter of an oversized drill hole designed for the placement of an artificial gravel pack shall allow a thickness of gravel or sand outside the casing sufficient to block the movement of natural materials into the well. The size of the openings in the casing or screen shall be based on the size of the gravel or sand used in the gravel pack.
    
    (1.) Gravel pack shall be well-rounded particles, 95 percent siliceous material, that are smooth and uniform, free of foreign material, properly sized, washed, and then disinfected immediately prior to or during placement. Gravel pack shall be placed in one uniformly continuous operation.
    
    (2.) After completion, the well shall be overpumped, surged, or otherwise developed to ensure free entry of water without sediment. A gravel-packed well shall be sealed in one of two ways to prevent pollution to the groundwater supply:
    If a permanent surface casing is not installed, the annular opening between the casing and the drill hole shall be sealed in the top 10 feet (3.05 m) with concrete or cement grout.
    
    If a permanent surface casing is installed, it shall extend to a depth of at least 10 feet (3.05 m). The annular opening between this outer casing and the inner casing shall be covered with a metal or cement seal.
    
    (3.) Gravel refill pipes, when used, shall be Schedule 40 steel pipe incorporated within the pump foundation and terminated with screwed or welded caps at least 12 inches (30 cm) above the pump house floor or concrete apron. Gravel refill pipes located in the grouted annular opening shall be surrounded by a minimum of 1-1/2 inches (3.8 cm) of grout. Protection from leakage of grout into the gravel pack or screen shall be provided.
  - (V) Radial water collector.
    
    (1.) Locations of all caisson construction joints and porthole assemblies shall be indicated on drawings. The caisson wall shall be reinforced to withstand the forces to which it will be subjected. The top of the caisson shall be covered with a watertight floor. The pump discharge piping shall not be placed through the caisson walls.
    
    (2.) Provisions shall be made to assure that radial collectors are essentially horizontal.
    
    (3.) All openings in the floor shall be curbed and protected from entrance of foreign material.
  - (VI) Infiltration lines. Where an infiltration line is used, the source shall be considered a surface source requiring treatment defined in Section 8(c) (i) unless, (1) the water system owner is in complete control of the surrounding property for a distance of 500 feet around the periphery of the infiltration system; (2) the area is fenced to exclude trespass; and (3) the infiltration collection lines are a minimum of 40 inches below the ground surface at all points within the infiltration collection system.
  - (VII) Limestone or sandstone wells. In consolidated formations, casing shall be driven a minimum of 5 feet into firm bedrock and cemented into place.
  - (VIII) Artesian wells.
    
    (1.) When artesian water is encountered in a well, unperforated casing shall extend into the confining layer overlying the artesian zone. This casing shall be adequately sealed with cement grout into the confining zone to prevent both surface and subsurface leakage from the artesian zone. The method of construction shall be such that during the placing of the grout and the time required for it to set, no water shall flow through or around the annular space outside the casing, and no water pressure sufficient to disturb the grout prior to final set shall occur. After the grout has set completely, drilling operations may be continued into the artesian zone. If leakage occurs around the well casing or adjacent to the well, the well shall be recompleted with any seals, packers or casing necessary to eliminate the leakage completely.
    
    (2.) If water flows at the surface, the well shall be equipped with valved pipe connections, watertight pump connections, or receiving reservoirs set at an altitude so that flow can be stopped completely. There shall be no direct connection between any discharge pipe and a sewer or other source of pollution.
  - (IX) Wells that penetrate more than one aquifer.
    
    (1.) Where a well penetrates more than one aquifer or water-bearing strata, every aquifer and/or strata shall be sealed off to prevent migration of water from one aquifer or strata to another. Strata shall be sealed off by placing impervious material opposite the strata and opposite the confining formation(s). The seal shall extend above and below the strata no less than 10 feet. The sealing material shall fill the annular space in the interval to be sealed, and the surrounding void spaces which might absorb the sealing material. The sealing material shall be placed from the bottom to the top of the interval to be sealed.
    
    (2.) Sealing material shall consist of neat cement, cement grout, or bentonite clay.
  - (X) Wells that encounter mineralized or polluted water.
    
    (1.) Any time during the construction of a well that mineralized water or water known to be polluted is encountered, the aquifer or aquifers containing such inferior quality water shall be adequately cased or sealed off so that water shall not enter the well, nor will it move up or down the annular space outside the well casing. If necessary, special seals or packers shall be installed to prevent movement of inferior quality water. Mineralized water may be used if it can be properly treated to meet all drinking water quality standards as determined by the administrator. When mineralized water is encountered, it shall not be mixed with any other waters from different aquifers within the well. If a well is penetrating multiple aquifers, mineralized water shall be excluded from the well if water is taken from other non-mineralized aquifers.
    
    (2.) In gravel packed wells, aquifers containing inferior quality water shall be sealed by pressure grouting, or with special packers or seals, to prevent such water from moving vertically in gravel packed portions of the well.
  - (XI) Conversion of existing oil or gas wells, or exploration test holes, into water wells.
    
    (1.) Existing oil and gas wells, seismic test holes, or mineral exploration holes may be converted for use as water wells provided that the wells can be completed to conform to the minimum construction standards cited in this chapter. This does not relieve the applicant from obtaining appropriate permits.
    
    (2.) Information on the geologic conditions encountered in the well at the time of the original drilling shall be used to determine what special construction standards shall be met in order to eliminate all movement of pollutants into the well or along the annular space surrounding the casing. If no original geologic information is available, an electric or other geophysical log is required to supplement known information.
- (C) Construction materials.
  - (I) Casing. The casing shall provide structural stability to prevent casing collapse during installation as well as drill hole wall integrity when installed, be of required size to convey liquid at a specified injection/recovery rate and pressure, and be of required size to allow for sampling.
    
    (1.) Temporary steel casing. Temporary steel casing used for construction shall be capable of withstanding the structural load imposed during its installation and removal.
    
    (2.) Permanent steel casing. Permanent steel casing pipe shall be new pipe meeting AWWA Standard A-100 specifications for water well construction. The casing shall have full circumferential welds or threaded coupling joints to assure a watertight construction.
    
    a. Standard and line pipe. This material shall meet one of the following specifications:
    API Std. 5L, "Specifications for Line Pipe."
    
    API Std. 5LX, "Specifications for High-Test Line Pipe."
    
    ASTM A53 "Standard Specification for Pipe Steel, Black and Hot Dipped, Zinc-Coated Welded and Seamless."
    
    ASTM A120 "Standard Specifications for Pipe, Steel, Black and Hot-Dipped Zinc-Coated (Galvanized) Welded and Seamless, for Ordinary Uses."
    
    ASTM A134 "Standards Specifications for Electric-Fusion (arc) - Welded Steel Plate Pipe (sizes NPS 16 inches and over)."
    
    ASTM A135 "Standard Specifications for Electric - Resistance - Welded Steel Pipe."
    
    ASTM A139 "Standard Specification for Electric-Fusion (arc) - Welded Steel Pipe (Sizes 4" and over)."
    
    ASTM A211 "Standard Specifications for Spiral - Welded Steel or Iron Pipe."
    
    AWWA C200 "AWWA Standard for Steel Water Pipe 6 inches and Larger."
    
    b. Structural steel. This material shall meet one of the following specifications:
    ASTM A36 "Standard Specification for Structural Steel."
    
    ASTM A242 "Standard Specifications for High Strength Low Alloy Structural Steel."
    
    ASTM A283 "Standard Specification for Low and Intermediate Tensile Strength Carbon Steel Plates, Shapes and Bars of Structural Quality."
    
    ASTM A441 "Tentative Specifications for High-Strength Low Alloy Structural Manganese Vanadium Steel."
    
    ASTM A570 "Standard Specification for Hot-Rolled Carbon Steel Sheet and Strip, Structural Quality."
    
    c. High-strength carbon steel sheets or "well casing steel". Each sheet of material shall contain mill markings which will identify the manufacturer and specify that the material is well casing steel which complies with the chemical and physical properties published by the manufacturer.
    
    d. Stainless steel casing shall meet the provisions of ASTM A409 "Standard Specification for Welded Large Diameter Austenitic Steel Pipe for Corrosive or High Temperature Service".
    
    (3.) Nonferrous casing materials. Nonferrous or plastic material may be used as a well casing. It must be resistant to the corrosiveness of the water and to the stresses to which it will be subjected during installation, grouting, and operation. The material shall be nontoxic. All joints shall be durable and watertight.
    
    a. Thermoplastics. This material shall meet the requirements of ASTM F 480 "Standard Specification for Thermoplastic Water Well Casing Pipe and Couplings made in Standard Dimension Ratios (SDR)".
    
    b. Thermosets. This material shall meet the requirements of the following specifications:
    ASTM D2996 "Standard Specification for Filament Wound Reinforced Thermosetting Resin Pipe."
    
    ASTM D2997 "Standard Specification for Centrifugally Cast Reinforced Thermosetting Resin Pipe."
    
    ASTM D3517 "Standard Specification for Reinforced Plastic Mortar Pressure Pipe."
    
    AWWA C950 "AWWA Standards for Glass - Fiber - Reinforced Thermosetting - Resin Pressure Pipe."
    
    c. Concrete pipe used for casing should conform to one of the following specifications:
    ASTM C14 "Standard Specifications for Concrete Sewer, Storm Drain, and Culvert Pipe."
    
    ASTM C76 "Standard Specification for Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe."
    
    AWWA C300 "AWWA Standards for Reinforced Concrete Pressure Pipe, Steel Cylinder Type, for Water and Other Liquids."
    
    AWWA C301 "AWWA Standards for Prestressed Concrete Pressure Pipe, Steel Cylinder Type, for Water and Other Liquids."
    
    (4.) Casing diameter. The casing diameter (inside diameter) shall be a minimum of one size larger than the largest dimension/diameter of the pump or pumping structure. If a reduction in casing diameter is made, there shall be adequate overlap of the casing to prevent misalignment and to prevent the movement of unstable sediment into the well. To prevent the migration of mineralized, polluted, or otherwise inferior quality water, lead or neoprene packers shall be installed to seal the annular space between casings.
  - (II) Packers. Packers shall be material that will not impart taste, odor, toxic substance, or bacterial contamination to the well water.
  - (III) Screens.
    
    (1.) Screens shall be constructed of materials resistant to damage by chemical action of groundwater or cleaning operations, and have size of openings based on sieve analysis of formation and/or gravel-pack materials. The screen shall have sufficient diameter to provide adequate specific capacity and low aperture entrance velocity. The entrance velocity shall not exceed 0.1 feet per second (3 cm/sec).
    
    (2.) The screen shall be installed so that the pumping water level remains above the screen under all operating conditions, and shall be provided with a bottom plate or washdown bottom fitting of the same material as the screen.
    
    (3.) For a nonhomogeneous aquifer having a uniformity coefficient less than 3.0 and an effective grain size less than 0.01 inches, an artificial filter or screen shall be used.
  - (IV) Grout and grouting requirements. All permanent well casing, except driven Schedule 40 steel casing, shall be surrounded by a minimum of 2 inches (5.1 cm) of grout. All temporary construction casings shall be removed. Where removal is not possible or practical, the casing shall be withdrawn at least 5 feet to ensure grout contact with the native formation.
    
    (1.) Neat cement grout. Cement conforming to ASTM Standard C150 and water, with not more than 6 gallons (13.62 L) of water per sack of cement, must be used for 2 inch (5.1 cm) openings. Additives used to increase fluidity must meet ASTM C494.
    
    (2.) Concrete grout. Equal parts of cement conforming to ASTM Standard C150 and sand, with not more than 6 gallons (13.62 L) of water per sack of cement, may be used for openings larger than 2 inches (5.1 cm). Where an annular opening larger than 4 inches (10 cm) is available, gravel not larger than 1/2 inch (1.27 cm) in size may be added.
    
    (3.) Clay seal. Where an annular opening greater than 6 inches (15.2 cm) is available a clay seal of clean local clay mixed with at least 10 percent swelling bentonite may be used.
    
    (4.) Application. Prior to grouting through creviced or fractured formations, bentonite or similar materials may be added to the annular opening in the manner indicated for grouting. After cement grouting is applied, work on the well shall be discontinued until the cement or concrete grout has properly set.
    Sufficient annular opening shall be provided to permit a minimum of 2 inches (5.1 cm) of grout around permanent casings, including couplings.
    
    When the annular opening is 4 or more inches (10 cm) and less than 100 feet (30.5 m) in depth and concrete grout is used, the grout may be placed by gravity through a grout pipe installed to the bottom of the annular opening in one continuous operation until the annular opening is filled.
    
    When the annular opening exceeds 6 inches (15.2 cm), and less than 100 feet (30.5 m) in depth and a clay seal is used, it may be placed by gravity.
    
    (5.) Guides. The casing must be provided with sufficient guides welded to the casing to permit unobstructed flow and uniform thickness of grout.
  - (V) Upper terminal well construction.
    
    (1.) Permanent casing for all groundwater sources shall project at least 12 inches (30.5 cm) above the pumphouse floor or concrete apron surface and at least 18 inches (0.46 m) above final ground surface. The concrete floor or apron shall slope away from the casing at a slope of 1 inch per foot (8.33 cm/m).
    
    (2.) Where a well house is constructed, the floor surface shall be at least 6 inches (15.2 cm) above the final ground elevation and shall slope away from the casing at a slope of 1/2 inch per foot (4.16 cm/m).
    
    (3.) Sites subject to flooding shall be provided with an earthen berm surrounding the casing and terminating at an elevation at least 2 feet (0.61 m) above the highest known flood elevation, or other suitable protection shall be provided.
    
    (4.) The top of the well casing at sites subject to flooding shall terminate at least 3 feet (0.91 m) above the 100-year flood level or the highest known flood elevation, whichever is higher.
    
    (5.) The casing and/or well house shall be protected from entrance by animals.
  - (VI) Development.
    
    (1.) Every well shall be developed to remove the native silts and clays, drilling mud or finer fraction of the gravel pack. Development shall continue until the maximum specific capacity is obtained from the completed well.
    
    (2.) Where chemical conditioning is required, the specifications shall include provisions for blasting and cleaning. Special attention shall be given to assure that the grouting and casing are not damaged by the blasting.
  - (VII) Capping requirements. A welded metal plate or a threaded cap shall be used for capping a well. A properly fitted, firmly driven, solid wooden plug may be used for capping a well until pumping equipment is installed. At all times during the progress of work, the contractor shall provide protection to prevent tampering with the well or entrance of surface water or foreign materials.
- (D) Well pumps, discharge piping and appurtenances.
  - (I) Line shaft pumps. Wells equipped with line shaft pumps shall have the casing firmly connected to the pump structure or have the casing inserted into a recess extending at least 1/2 inch into the pump base, have the pump foundation and base designed to prevent water from coming into contact with the joint, and avoid the use of oil lubrication at pump settings less than 400 feet (122 m).
  - (II) Submersible pumps. Where a submersible pump is used, the top of the casing shall be effectively sealed against the entrance of water under all conditions of vibration or movement of conductors or cables. The electrical cable shall be firmly attached to the rise pipe at 20 foot (6.1 m) intervals or less, and the pump shall be located at a point above the top of the well screen.
  - (III) Discharge piping.
    
    (1.) The discharge piping shall have control valves and appurtenances located above the wellhouse floor. The piping shall be protected against the entrance of contamination and be equipped with a check valve, a shutoff valve, a pressure gauge, a means of measuring flow, and a smooth-nosed sampling tap located at a point where positive pressure is maintained. Where a submersible pump is used, a check valve shall be located in the casing in addition to the check valve located above ground to prevent negative pressures on the discharge piping.
    
    (2.) For pipes equipped with an air release-vacuum relief valve, the valve shall be located upstream from the check valve, with exhaust/relief piping terminating in a downturned position at least 18 inches (0.46 m) above the floor and covered with a 24 mesh corrosion-resistant screen. The discharge piping shall be valved to permit test pumping and control of each well.
    
    (3.) All exposed piping, valves and appurtenances shall be protected against physical damage and freezing.
    
    (4.) The piping shall be properly anchored to prevent movement, and shall be protected against surge or water hammer.
    
    (5.) The discharge piping shall be provided with a means of pumping to waste, but shall not be directly connected to a sewer.
  - (IV) Pitless well units. A pitless adaptor or well house shall be used where needed to protect the water system from freezing. A frost pit may be used only in conjunction with a properly protected pitless adaptor.
    
    (1.) All pitless units shall be shop fabricated from the point of connection with the well casing to the unit cap or cover. They shall be threaded or welded to the well casing, and be of watertight construction throughout. The materials and weight shall be at least equivalent and compatible to the casing.
    
    (2.) Pitless units shall have field connection to the lateral discharge from the pitless unit of threaded, flanged or mechanical joint connection, and the top of the pitless unit shall terminate at least 18 inches (0.46 m) above final ground elevation or 3 feet above the 100-year flood level or the highest known flood elevation, whichever is higher.
    
    (3.) Provisions shall be made to disinfect the well. The unit shall have facilities to measure water levels in the well; a cover at the upper terminal of the well that will prevent the entrance of contamination; a contamination-proof entrance connection for electrical cable; an inside diameter as great as that of the well casing, up to and including casing diameters of 12 inches (30.5 cm), to facilitate work and repair on the well, pump, or well screen; and at least one check valve within the well casing.
  - (V) Casing vent. Provisions shall be made for venting the well casing to atmosphere. The vent shall terminate in a downturned position, at or above the top of the casing or pitless unit in a minimum 1-1/2 inch (3.8 cm) diameter opening covered with a 24 mesh corrosion-resistant screen. The pipe connecting the casing to the vent shall be of adequate size to provide rapid venting of the casing.
  - (VI) Water level management. Every well greater than 4 inches (10 cm) in diameter shall be equipped with an access port that will allow for the measurement of the depth to the water surface; or in the case of a flowing artesian well, with a pressure gauge that will indicate pressure. An air line used for level measurement shall be provided on all wells greater than 4 inches (10 cm) in diameter. Installation of water level measuring equipment shall be made using corrosion-resistant materials attached firmly to the drop pipe or pump column and in such a manner as to prevent entrance of foreign materials.
  - (VII) Discharge measuring device. Every well shall be piped so that a device capable of measuring the total well discharge can be placed in operation at the well for well testing. Every well field (or when only one well is present, every well) shall have a device capable of measuring the total discharge.
  - (VIII) Observation wells. Observation wells shall be constructed in accordance with the requirements for permanent wells if they are to remain in service after completion of a water supply well. They shall be protected at the upper terminal to preclude entrance of foreign materials.
  - (IX) Well abandonment. Test wells and groundwater sources which are not in use shall be sealed in accordance with requirements of Chapter 26, Water Quality Rules and Regulations.
    Wells shall be sealed by filling with neat cement grout. The filling materials shall be applied to the well hole through a pipe, tremie, or bailer.

020-12 Wyo. Code R. § 12-9