Utah Admin. Code R655-4-11 - Well Drilling and Construction Requirements

11.0 General. Standards in this section apply to wells greater than 30 feet. For shallow water well requirements, see Section R655-4-17.

11.1 Approved Products, Materials, and Procedures. 11.1.1 Any product, material or procedure designed for use in the drilling, construction, cleaning, renovation, development pump installation or repair, or abandonment of water production or non-production wells, which has received certification and approval for its intended use by the National Sanitation Foundation (NSF) under ANSI-NSF Standard 60 or 61, the American Society for Testing Materials (ASTM), the American Water Works Association (AWWA) or the American National Standards Institute (ANSI) may be utilized. Other products, materials or procedures may also be utilized for their intended purpose upon manufacturers certification that they meet or exceed the standards or certifications referred to in this section and upon state engineer approval.

11.1.2 Public supply wells are also regulated by the Division of Drinking Water, and there are additional construction requirements in Rule R309-515.

11.2 Well Casing - General

11.2.1 Drillers Responsibility. It shall be the sole responsibility of the well driller to determine the suitability of any type of well casing for the particular well being constructed, in accordance with these minimum requirements.

11.2.2 Casing Stick-up. The well casing shall extend a minimum of 18 inches above finished ground level and the natural ground surface should slope away from the casing. A secure sanitary, weatherproof mechanically secured cap, seal, or a completely welded cap shall be placed on the top of the well casing to prevent contamination of the well. If a vent is placed in the cap, it shall be properly screened to prevent access to the well by debris, insects, or other animals.

11.2.3 Steel Casing. All steel casing installed in Utah shall be in new or like-new condition, being free from pits or breaks, clean with all potentially dangerous chemicals or coatings removed, and shall meet the minimum specifications listed in Table 6 of this rule. To utilize steel well casing, or steel blank casing and screen combinations, that does not fall within the categories specified in Table 6, the driller shall receive written approval from the state engineer. All steel casing installed in Utah shall meet or exceed the minimum ASTM, ANSI, or AWWA standards for steel pipe as described in Subsection R655-4-11 (11.1) unless otherwise approved by the state engineer. Applicable standards may include and are incorporated by reference into this rule:

AWWA A100-AWWA Standard for Water Wells, 2020 Edition.

ASTM A53/A53M-20 Standard Specifications for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless, 2020 Edition.

ASTM A139/A139M-16 Standard Specification for Electric-Fusion (Arc)-Welded Steel Pipe (NPS 4 and over), 2016 Edition.

AWWA C200-2017 Standard for Steel Water Pipe, 6 Inches and Larger, 2017 Edition.

ASTM A589/A589M-06 (2018) Standard Specification for Seamless and Welded Carbon Steel Water-Well Pipe, 2018 Edition.

ASTM A106/A106M-19a Standard Specification for Seamless Carbon Steel Pipe for High Temperature Service, 2019 Edition

ASTM A778/A778M-16 (2021) Standard Specifications for Welded, Unannealed Austenitic Stainless Steel Tubular Products, 2021 Edition.

ASTM A252/A252M-19 Standard Specification for Welded and Seamless Steel Pipe Piles, 2019 Edition.

ASTM A312/A312M-21 Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes, 2021 Edition.

ASTM A409/A409M-19 Standard Specification for Welded Large Diameter Austenitic Steel Pipe for Corrosive or High Temperature Service, 2019 Edition.

ASTM A606/A606M-18 Standard Specification For Steel, Sheet And Strip, High-Strength, Low-Alloy, Hot-Rolled And Cold-Rolled, With Improved Atmospheric Corrosion Resistance, 2018 Edition.

TABLE 6 Minimum Wall Thickness for Steel Well Casing
Depth Nominal Casing Diameter	0 to 200 feet	200 to 300 feet	300 to 400 feet	400 to 600 feet	600 to 800 feet	800 to 1000 feet	1000 to 1500 feet	1500 to 2000 feet
5	250	250	250	250	250	250	250	250
6	250	250	250	250	250	250	250	250
8	250	250	250	250	250	250	250	250
10	250	250	250	250	250	250	312	312
12	250	250	250	250	250	250	312	312
14	250	250	250	250	312	312	312	312
16	250	250	312	312	312	312	375	375
18	250	312	312	312	375	375	375	438
20	250	312	312	312	375	375	375	438
22	312	312	312	375	375	375	375	438
24	312	312	375	375	375	438
30	312	375	375	438	438	500
Note: Minimum wall thickness is in inches. For nominal casing diameters less than five inches, the minimum wall thickness must be equivalent to ASTM Schedule 40. For any other casing diameter not addressed Subsection R655-4-11 (11.2), approval by the state engineer is required. 0.250 = 1/4, 0.312 = 5/16, 0.375 = 3/8, 0.438 = 7/16.

11.2.4 Plastic and Other Non-metallic Casing.

11.2.4.1 Materials. PVC well casing and screen may be installed in Utah upon obtaining permission of the well owner. Other types of non-metallic casing or screen must be approved by the state engineer before installation. Plastic well casing and screen shall be manufactured and installed to conform with the American National Standards Institute (ANSI) or the American Society for Testing and Materials (ASTM) Standard F480-14, 2022 Edition, which is incorporated by reference to this rule. Casing and screen meeting this standard is normally marked "WELL CASING" and with the ANSI-ASTM designation "F480, SDR-17 or similar standard dimension ratio." All plastic casing and screen for use in potable water supplies shall be manufactured to be acceptable to the American National Standards Institute's National Sanitation Foundation (NSF) standard 61. Other types of plastic casings and screens may be installed upon manufacturers certification that such casing meets or exceeds the ASTM-SDR specification or ANSI-NSF approval and upon state engineer approval.

11.2.4.2 Minimum Wall Thickness and Depth Requirements. PVC well casing and screen for non-production wells with a nominal diameter equal to or less than four inches shall meet the minimum wall thickness required under ASTM Standard F480-95 SDR 21 or a Schedule 40 designation. PVC well casing and screen used for non-production well purposes with a nominal diameter greater than four inches shall meet the minimum wall thickness required under ASTM Standard F480-95 SDR 17 or a Schedule 80 designation. PVC well casing and screen used for water production well purposes shall meet the minimum wall thickness required under ASTM Standard F480-95 SDR 17 or a Schedule 80 designation. Additionally, caution should be used when other than factory slots or perforations are added to PVC well casing. The installation of hand cut slots or perforations significantly reduces the collapse strength tolerances of unaltered casings. The depth at which plastic casing and screen is placed in a well shall conform to the minimum requirements and restrictions as outlined in ASTM Standard F480-14, 2022 Edition and to PVC casing manufacturer recommendations. Liner pipe does not need to meet these wall thickness requirements if it is placed inside of a casing that does meet these wall thickness requirements.

11.2.4.3 Fiberglass Casing. Fiberglass reinforced plastic well casings and screens may be installed in wells upon obtaining permission of the well owner. All fiberglass casing or screens installed in wells for use in potable water supplies shall be manufactured to be acceptable by ANSI-NSF Standard 61 and upon state engineer approval.

11.2.4.4 Driving Non-metallic Casing. Non-metallic casing shall not be driven, jacked, or dropped and may only be installed in an oversized borehole.

11.2.4.5 Protective Casing. If plastic or other non-metallic casing is utilized, the driller shall install a protective steel casing which complies with Subsection R655-4-11 (11.2.3) or an equivalent protective covering approved by the state engineer over and around the well casing at ground surface to a depth of at least 2-1/2 feet. If a pitless adapter is installed on the well, the bottom of the protective cover shall be placed above the pitless adapter or well connection. If the pitless adapter is placed in the protective casing, the protective casing shall extend below the pitless entrance in the well casing and be sealed both on the outside of the protective casing and between the protective casing and well casing. The protective cover shall be sealed in the borehole in accordance with the requirements of Subsection R655-4-11 (11.4). The annular space between the protective cover and non-metallic casing shall also be sealed with acceptable materials in accordance with Subsection R655-4-11 (11.4). A sanitary, weather-tight seal or a completely welded cap shall be placed on top of the protective cover, thus enclosing the well itself. If the sanitary seal is vented, screens shall be placed in the vent to prevent debris insects, and other animals from entering the well. This protective casing requirement does not apply to monitor wells.

11.3 Casing Joints.

11.3.1 General. All well casing joints shall be made water tight. In instances in which a reduction in casing diameter is made, there shall be enough overlap of the casings to prevent misalignment and to insure the making of an adequate seal in the annular space between casings to prevent the movement of unstable sediment or formation material into the well, in addition to preventing the degradation of the water supply by the migration of inferior quality water through the annular space between the two casings.

11.3.2 Steel Casing. All steel casing shall be screw-coupled or welded. If the joints are welded, the weld shall meet American Welding Society standards and be at least as thick as the wall thickness of the casing and shall consist of at least two beads for the full circumference of the joint and be fully penetrating. Spot welding of joints is prohibited. State engineer approval must be obtained for other steel casing joint types such as splined joints or dielectric couplings.

11.3.3 Plastic Casing. All plastic well casing shall be mechanically screw-coupled, chemically welded, cam-locked or lug coupled to provide water tight joints as per ANSI-ASTM F480-95. Metal screws driven into casing joints shall not be long enough to penetrate the inside surface of the casing. Metal screws should be used only when surrounding air temperatures are below 50 degrees Fahrenheit (F) which retards the normal setting of the cement. Solvent-welded joints shall not impart taste, odors, toxic substances, or bacterial contamination to the water in the well.

11.4 Surface Seals and Interval Seals.

11.4.1 General. Before the drill rig is removed from the drill site of a well, a surface seal shall be installed. Well casings shall be sealed to prevent the possible downward movement of contaminated surface waters in the annular space around the well casing. The seal shall also prevent the upward movement of artesian waters within the annular space around the well casing. Depending upon hydrogeologic conditions around the well, interval seals may need to be installed to prevent the movement of groundwater either upward or downward around the well from zones that have been cased out of the well due to poor water quality or other reasons. The following surface and interval seal requirements apply equally to rotary drilled, cable tool drilled, bored, jetted, augered, and driven wells unless otherwise specified.

11.4.2 Seal Material.

11.4.2.1 General. The seal material shall consist of neat cement grout, sand cement grout, unhydrated bentonite, or bentonite grout as defined in Section R655-4-2. Use of sealing materials other than those listed in Section R655-4-11 must be approved by the state engineer. Bentonite drilling fluid, also known as drilling mud, dry drilling bentonite, or drill cuttings are not an acceptable sealing material. In no case shall drilling mud, drill cuttings, drill chips, or puddling clay be used, or allowed to fill, partially fill, or fall into the required sealing interval of a well during construction of the well. The annular space to be grouted must be protected from collapse and the introduction of materials other than grout. All hydrated sealing materials, such as neat cement grout, sand cement grout, and bentonite grout, shall be placed by tremie pipe, pumping, or pressure from the bottom of the seal interval upwards in one continuous operation when placed below a depth of 30 feet or when placed below static groundwater level. Neat cement and sand cement grouts must be allowed to cure a minimum of 24 hours before well drilling, construction, or testing may be resumed. Allowable setting times may be reduced or lengthened by use of accelerators or retardants specifically designed to change setting time, at the approval of the state engineer. The volume of annular space in the seal interval shall be calculated by the driller to determine the estimated volume of seal material required to seal the annular space. The driller shall place at least the volume of material equal to the volume of annular space, thus ensuring that a continuous seal is placed. The driller shall maintain the well casing centered in the borehole during seal placement using centralizers or other means to ensure that the seal is placed radially and vertically continuous. Neat cement and sand cement grout shall not be used for surface or interval seals with PVC and other approved non-metallic casing unless specific state engineer approval is obtained.

11.4.2.2 Bentonite Grout. Bentonite used to prepare grout for sealing shall have the ability to gel; not separate into water and solid materials after it gels; have a hydraulic conductivity or permeability value of 10E-7 centimeters per second or less; contain at least 20% solids by weight of bentonite, and have a fluid weight of 9.5 pounds per gallon or greater and be specifically designed for sealing. In addition, if a bentonite grout is to be placed in the vadose zone, also known as the unsaturated interval, then clean rounded fine sand shall be added to the bentonite grout to increase the overall solids content and stabilize the grout from dehydrating and cracking in that interval. For 20% solids bentonite grout, at least 100 pounds of clean rounded fine sand shall be added per 50 pounds of bentonite. For 30% solids bentonite grout, at least 50 pounds of clean fine sand shall be added per 50 pounds of bentonite. Bentonite grout shall not be used for sealing intervals of fractured rock or sealing intervals of highly unstable material that could collapse or displace the sealing material, unless otherwise approved by the state engineer. Bentonite grout shall not be used as a sealing material where rapidly flowing groundwater might erode it. Bentonite or polymer drilling fluid, also known as drilling mud, does not meet the definition of a grout with respect to density, gel strength, and solids content and shall not be used for sealing purposes. At no time shall bentonite grout contain materials that are toxic, polluting, develop odor or color changes, or serve as a micro-bacterial nutrient. All bentonite grout shall be prepared and installed according to the manufacturer's instructions and this rule. All additives must be certified by a recognized certification authority such as NSF and approved by the state engineer. All bentonite used in any well shall be certified by NSF-ANSI approved standards for use in potable water supply wells, or equivalent standards as approved by the state engineer.

11.4.2.3 Unhydrated Bentonite. Unhydrated bentonite, such as granular, tabular, pelletized, or chip bentonite, may be used in the construction of well seals above a depth of 50 feet. Unhydrated bentonite can be placed below a depth of 50 feet when placed inside the annulus of two casings, when placed using a tremie pipe, or by using a placement method approved by the state engineer. The bentonite material shall be specifically designed for well sealing and be within industry tolerances. All unhydrated bentonite used for sealing must be free of organic polymers and other contamination. Placement of bentonite shall conform to the manufacturer's specifications and instructions and result in a seal free of voids or bridges. Granular or powdered bentonite shall not be placed under water by gravity feeding from the surface. When placing unhydrated bentonite, a sounding or tamping tool shall be run in the sealing interval during pouring to measure fill-up rate, verify a continuous seal placement, and to break up possible bridges or cake formation.

11.4.3 Seal and Unperforated Casing Placement.

11.4.3.1 General Seal Requirements. The surface seal must be placed in an annular space that has a minimum diameter of four inches larger than the nominal size of the permanent well casing. This amounts to a 2-inch annulus. The surface seal must extend from land surface to a minimum depth of 30 feet. The completed surface seal must fully surround the permanent well casing, must be evenly distributed, free of voids, and extend to undisturbed or recompacted soil. In unconsolidated formations such as gravels, sands, or other unstable conditions when the use of drilling fluid or other means of keeping the borehole open are not employed, either a temporary surface casing with a minimum depth of 30 feet and a minimum nominal diameter of four inches greater than the outermost permanent casing shall be utilized to ensure proper seal placement or the well driller shall notify the state engineer's office that the seal will be placed in a potentially unstable open borehole without a temporary surface casing by telephone or fax in conjunction with the Start Card submittal to provide an opportunity for the state engineer's office to inspect the placement of the seal. If a temporary surface casing is utilized, the surface casing shall be removed in conjunction with the placement of the seal. Alternatively, conductor casing may be sealed permanently in place to a depth of 30 feet with a minimum 2-inch annular seal between the surface casing and borehole wall. If the temporary surface casing is to be removed, the surface casing shall be withdrawn as sealing material is placed between the outermost permanent well casing and borehole wall. The sealing material shall be kept at a sufficient height above the bottom of the temporary surface casing as it is withdrawn to prevent caving of the borehole wall. If the temporary conductor casing is driven in place without a 2-inch annular seal between the surface casing and borehole wall, the surface casing shall be removed. Specific state engineer approval must be obtained on a case by case basis for any variation of these requirements. Surface seals and unperforated casing shall be installed in wells located in unconsolidated formation such as sand and gravel with minor clay or confining units; unconsolidated formation consisting of stratified layers of materials such as sand, gravel, and clay or other confining units; and consolidated formations according to the following procedures.

11.4.3.2 Unconsolidated Formation without Significant Confining Units. This includes wells that penetrate an aquifer overlain by unconsolidated formations such as sand and gravel without significant clay beds of at least six feet in thickness or other confining formations. The surface seal must be placed in a 2-inch annular space to a minimum depth of 30 feet. Permanent unperforated casing shall extend at least to a depth of 30 feet and also extend below the lowest anticipated pumping level. Additional casing placed in the open borehole below the required depths noted in Section R655-4-11 shall meet the casing requirements of Subsection R655-4-9 (9.2) unless the casing is installed as a liner inside a larger diameter approved casing.

11.4.3.3 Unconsolidated Formation with Significant Confining Units. This includes wells that penetrate an aquifer overlain by clay or other confining formations that are at least six feet thick. The surface seal must be placed in a 2-inch annular space to a minimum depth of 30 feet and at least five feet into the confining unit above the water bearing formation. Unperforated casing shall extend from ground surface to at least 30 feet and to the bottom of the confining unit overlying the water bearing formation. If necessary to complete the well, a smaller diameter casing, liner, or well screen may be installed below the unperforated casing. The annular space between the two casings shall be sealed with grout, bentonite, or a mechanical packer. Additional casing placed in the open borehole below the required depths noted in Section R655-4-11 shall meet the casing requirements of Subsection R655-4-11 (11.2) unless the casing is installed as a liner inside a larger diameter approved casing.

11.4.3.4 Consolidated Formation. This includes drilled wells that penetrate an aquifer, either within or overlain by a consolidated formation. The surface seal must be placed in a 2-inch annular space to a minimum depth of 30 feet and at least five feet into competent consolidated formation. Unperforated permanent casing shall be installed to extend to a depth of at least 30 feet and the lower part of the casing shall be driven and sealed at least five feet into the consolidated formation. If necessary to complete the well, a smaller diameter casing, liner, or well screen may be installed below the unperforated casing. The annular space between the two casings shall be sealed with grout, bentonite, or a mechanical packer. Additional casing placed in the open borehole below the required depths noted in Section R655-4-11 shall meet the casing requirements of Subsection R655-4-11 (11.2) unless the casing is installed as a liner inside a larger diameter approved casing.

11.4.3.5 Sealing Artesian Wells. Unperforated well casing shall extend into the confining stratum overlying the artesian zone, and shall be adequately sealed into the confining stratum to prevent both surface and subsurface leakage from the artesian zone. If leaks occur around the well casing or adjacent to the well, the well shall be completed with the seals, packers, or casing necessary to eliminate the leakage. The driller shall not move the drilling rig from the well site until leakage is completely stopped, unless authority for temporary removal of the drilling rig is granted by the state engineer, or when loss of life or property is imminent. If the well flows naturally at land surface due to artesian pressure, the well shall be equipped with a control valve so that the flow can be completely stopped. The control valve must be available for inspection by the state engineer at all times. All flowing artesian water supply wells shall be tested for artesian shut-in pressure in pounds per square inch and rate of flow in cubic feet per second, or gallons per minute, under free discharge conditions. This data shall be reported on the well log.

11.4.3.6 Exceptions: With state engineer approval, exceptions to minimum seal depths can be made for shallow wells where the water to be produced is at a depth less than 30 feet. In no case shall a surface seal extend to a total depth less than 10 feet below land surface.

11.4.4 Interval Seals. Formations containing undesirable materials such as fine sand and silt that can damage pumping equipment and result in turbid water, contaminated groundwater, or poor quality groundwater must be sealed off so that the unfavorable formation cannot contribute to the performance and quality of the well. These zones, as well as zones with significantly differing pressures, must also be sealed to eliminate the potential of cross contamination or commingling between two aquifers of differing quality and pressure. Unless approved by the state engineer, construction of wells that cause the commingling or cross connection of otherwise separate aquifers is not allowed.

11.4.5 Other Sealing Methods. In wells where the methods of well sealing described in Section R655-4-11 do not apply, special sealing procedures can be approved by the state engineer upon written request by the licensed well driller.

11.5 Special Requirements for Oversized and Gravel Packed Wells. This section applies to wells in which casing is installed in an open borehole without driving or drilling in the casing and an annular space is left between the borehole wall and well casing. For example, mud rotary wells, flooded reverse circulation wells, and air rotary wells in open bedrock.

11.5.1 Oversized Borehole. The diameter of the borehole shall be at least four inches larger than the outside diameter of the well casing to be installed to allow for proper placement of the gravel pack or formation stabilizer and adequate clearance for grouting and surface seal installations. To accept a smaller diameter casing in any oversized borehole penetrating unconsolidated or stratified formations, the annular space must be sealed in accordance with Subsection R655-4-11 (11.4). To minimize the risk of:

1) borehole caving or collapse;

2) casing failure or collapse; or

3) axial distortion of the casing, it is required that the entire annular space in an oversized borehole between the casing and borehole wall be filled with formation stabilizer such as approved seal material, gravel pack, filter material or other state engineer-approved materials. Well casing placed in an oversized borehole should be suspended at the ground surface until all formation stabilizer material is placed to reduce axial distortion of the casing if it is allowed to rest on the bottom of an open oversized borehole. To accept a smaller diameter casing, the annular space in an oversized borehole penetrating unconsolidated formations with no confining layer must be sealed in accordance with Subsection R655-4-11 (11.4) to a depth of at least 30 feet or from static water level to ground surface, whichever is deeper. The annular space in an oversized borehole penetrating stratified or consolidated formations must be sealed in accordance with Subsection R655-4-11 (11.4) to a depth of at least 30 feet or five feet into an impervious strata such as clay or competent consolidated formation overlying the water producing zones back to ground surface, whichever is deeper. Especially in the case of an oversized borehole, the requirements of Subsection R655-4-11 (11.4.4) regarding interval sealing must be followed.

11.5.2 Gravel Pack or Filter Material. The gravel pack or filter material shall consist of clean, well-rounded, chemically stable grains that are smooth and uniform. The filter material should not contain more than 2% by weight of thin, flat, or elongated pieces and should not contain organic impurities or contaminants of any kind. To assure that no contamination is introduced into the well via the gravel pack, the gravel pack must be washed with a minimum 100 ppm solution of chlorinated water or dry hypochlorite mixed with the gravel pack at the surface before it is introduced into the well. See Table 7 of this rule for required amount of chlorine material.

11.5.3 Placement of Filter Material. All filter material shall be placed using a method that through common usage has been shown to minimize a) bridging of the material between the borehole and the casing, and b) excessive segregation of the material after it has been introduced into the annulus and before it settles into place. It is not acceptable to place filter material by pouring from the ground surface unless proper sounding devices are utilized to measure dynamic filter depth, evaluate pour rate, and minimize bridging and formation of voids.

11.5.4 No Surface Casing Used. If no permanent conductor casing is installed, neat cement grout, sand cement grout, bentonite grout, or unhydrated bentonite seal shall be installed in accordance with Subsection R655-4-11 (11.4).

11.5.5 Permanent Conductor Casing Used. If permanent conductor casing is installed, it shall be unperforated and installed and sealed in accordance with Subsection R655-4-11 (11.4). After the gravel pack has been installed between the conductor casing and the well casing, the annular space between the two casings shall be sealed by either welding a watertight steel cap between the two casings at land surface or filling the annular space between the two casings with neat cement grout, sand cement grout, bentonite grout, or unhydrated bentonite from at least 50 feet to the surface and in accordance with Subsection R655-4-11 (11.4). If a hole will be created in the permanent conductor casing to install a pitless adapter into the well casing, the annual space between the conductor casing and well casing shall be sealed to at least a depth of 30 feet with neat cement grout, sand cement grout, bentonite grout, or unhydrated bentonite. A waterproof cap or weld ring sealing the two casings at the surface by itself without the annular seal between the two casings is unacceptable when a pitless adapter is installed in this fashion. Moreover in this case, the annular space between the surface casing and well casing must be at least 2 inches to facilitate seal placement.

11.5.6 Gravel Feed Pipe. If a gravel feed pipe, used to add gravel to the gravel pack after well completion, is installed, the diameter of the borehole in the sealing interval must be at least four inches in diameter greater than the permanent casing plus the diameter of the gravel feed pipe. The gravel feed pipe must have at least 2-inches of seal between it and the borehole wall. The gravel feed pipe must extend at least 18 inches above ground and must be sealed at the top with a watertight cap or plug.

11.5.7 Other Gravel Feed Options. If a permanent surface casing or conductor casing is installed in the construction of a filter pack well, a watertight, completely welded, steel plate, also known as a weld ring, at least 3/16 of an inch in thickness shall be installed between the inner production casing and the outer surface or conductor casing at the wellhead. A watertight fill port with threaded cap may be installed for placing additional filter pack material in the well.

11.6 Protection of the Aquifer.

11.6.1 Drilling Fluids and LCMs. The well driller shall take due care to protect the producing aquifer from clogging or contamination. Organic substances or phosphate-based substances shall not be introduced into the well or borehole during drilling or construction. Every effort shall be made to remove all substances and materials introduced into the aquifer or aquifers during well construction. "Substances and materials" shall mean all bentonite-and polymer-based drilling fluids, filter cake, and any other inorganic substances added to the drilling fluid that may seal or clog the aquifer. All polymers and additives used in any well shall be certified by NSF-ANSI approval standards for use in potable water supply wells, or equivalent standards as approved by the state engineer. The introduction of lost circulation materials (LCM's) during the drilling process shall be limited to those products that will not present a potential medium for bacterial growth or contamination. Only LCM's which are non-organic, which can be safely broken down and removed from the borehole, may be utilized. Unacceptable LCM materials include paper or wood products, brans, hulls, grains, starches, hays or straws, and proteins. This is especially important in the construction of wells designed to be used as a public water system supply. All polymers and additives used in any well shall be certified by NSF-ANSI approval standards for use in potable water supply wells, or equivalent standards as approved by the Division. The product shall be clearly labeled as meeting these standards. Polymers and additives must be designed and manufactured to meet industry standards to be nondegrading and must not act as a medium which will promote growth of microorganisms.

11.6.2 Containment of Drilling Fluid. Drilling or circulating fluid introduced into the drilling process shall be contained in a manner to prevent surface or subsurface contamination and to prevent degradation of natural or man-made water courses or impoundments. Requirements regarding the discharges to waters of the state are promulgated under Section R317-8-2 and regulated by the Utah Division of Water Quality, 801-536-6146. Pollution of waters of the state is a violation of Title 19 Chapter 5, Utah Water Quality Act.

11.6.3 Mineralized, Contaminated or Polluted Water. When a water bearing stratum that contains nonpotable mineralized, contaminated or polluted water is encountered, the stratum shall be adequately sealed off so that contamination or co-mingling of the overlying or underlying groundwater zones will not occur. Water bearing zones with differing pressures must also be isolated and sealed off in the well to avoid aquifer depletion, wasting of water, and reduction of aquifer pressures.

11.6.4 Down-hole Equipment. All tools, drilling equipment, and materials used to drill, repair, renovate, clean, or install a pump in a well shall be free of contaminants before beginning well construction or other in-well activity. Contaminants include lubricants, fuel, or bacteria that will reduce the well efficiency, and any other items that will be harmful to public health or the resource or reduce the life of the water well. It is recommended that excess lubricants placed on drilling equipment be wiped clean before insertion into the borehole.

11.6.5 Well Disinfection and Chlorination of Water. No contaminated or untreated water shall be placed in a well during construction. Water should be obtained from a chlorinated municipal system. Where this is not possible, the water must be treated to give at least 100 parts per million free chlorine residual. Upon completion of a well or work on a well, the driller or pump installer shall disinfect the well using accepted disinfection procedures to give at least 100 parts per million free chlorine residual equally distributed in the well water from static level to the bottom of the well. A chlorine solution designated for potable water use prepared with either calcium hypochlorite in powdered, granular, or tablet form or sodium hypochlorite in liquid form shall be used for water well disinfection. Off-the-shelf chlorine compounds intended for home laundry use, pool or fountain use should not be used if they contain additives such as antifungal agents, silica, or scents. Products labeled with "Ultra" may contain these additives. Table 7 provides the amount of chlorine compound required per 100 gallons of water or 100 feet linear casing volume of water to mix a 100 parts per million solution. Disinfection situations not depicted in Table 7 must be approved by the state engineer. Additional recommendations and guidelines for water well system disinfection are available from the state engineer upon request.

TABLE 7 Amount of Chlorine Compound for Each 100 Feet of Water Standing in the Well - 100 ppm solution
Well Diameter inches	Ca-HyCLT* 25% HOCL ounces	Ca-HyCLT 65% HOCL ounces	Na-HyCLT** 12-trade % fluid ounces	Na-HyCLT** 100% Cl2 pounds
2	1.00	0.50	3.5	0.03
4	3.50	1.50	7.0	0.06
6	8.00	3.00	16.0	0.12
8	14.50	5.50	28.0	0.22
10	22.50	8.50	45.0	0.34
12	32.50	12.00	64.0	0.50
14	44.50	16.50	88.0	0.70
16	58.00	26.00	112	0.88
20	90.50	33.00	179	1.36
For every 100 gallons of water, add:	5.50	2.00	11.5	0.09
Note: *Calcium Hypochlorite - solid **Sodium Hypochlorite - liquid ***Liquid Chlorine

11.7 Special Requirements.

11.7.1 Explosives. Explosives used in well construction shall not be detonated within the section of casing designed or expected to serve as the surface seal of the completed well, whether or not the surface seal has been placed. If explosives are used in the construction of a well, their use shall be reported on the official well log. In no case shall explosives, other than explosive shot perforators specifically designed to perforate steel casing, be detonated inside the well casing or liner pipe.

11.7.2 Access Port. Every well shall be equipped with a usable access port so that the position of the water level, or pressure head, in the well can be measured at all times.

11.7.3 Completion or Abandonment. A licensed driller shall not remove the drill rig from a well site unless the well is completed or abandoned. Completion of a well shall include all surface seals, gravel packs or curbs required. Dry boreholes, or otherwise unsuccessful attempts at completing a well, shall be properly abandoned in accordance with Section R655-4-14. Upon completion, all wells shall be equipped with a watertight, tamper-resistant casing cap or sanitary seal.

11.7.4 Surface Security. If it becomes necessary for the driller to temporarily discontinue the drilling operation before completion of the well or otherwise leave the well or borehole unattended, the well or borehole must be covered securely to prevent contaminants from entering the casing or borehole and rendered secure against entry by children, vandals, domestic animals, and wildlife.

11.7.5 Pitless Adapters and Units. Pitless adapters or units are acceptable to use with steel well casing as long as they are installed in accordance with manufacturers recommendations and specifications as well as meet the Water Systems Council Pitless Adapter Standard (PAS-97) which are incorporated by reference and are available from Water Systems Council, 13 Bentley Dr., Sterling, VA 20165, phone 703-430-6045, fax 703-430-6185, email watersystemscouncil.org. The pitless adaptor, including the cap or cover, casing extension, and other attachments, must be so designed and constructed to be secure, water tight, and to prevent contamination of the potable water supply from external sources. Pitless wellhead configurations shall have suitable access to the interior of the well to measure water level and for well disinfection purposes. Pitless configurations shall be of watertight construction throughout and be constructed of materials at least equivalent to and having wall thickness and strength compatible to the casing. Pitless adapters or units are not recommended to be mounted on PVC well casing. If a pitless adapter is to be used with PVC casing, it should be designed for use with PVC casing, and the driller should ensure that the weight of the pump and column do not exceed the strength of the PVC well casing. If it is known that a pitless adapter or unit will be installed on a well, a cement grout seal shall not be allowed within the pitless unit or pitless adaptor sealing interval as the well is being constructed. The pitless adapter or unit sealing interval shall be sealed with unhydrated bentonite as the well is constructed and before pitless installation. Upon pitless adapter or unit installation, the surface seal below the pitless connection shall be protected and maintained. After the pitless adapter or unit has been installed, the associated excavation around the well from the pitless connection to ground surface shall be backfilled and compacted with low permeability fill that includes clay. The pitless adapter or unit, including the cap or cover, pitless case and other attachments, shall be designed and constructed to be watertight to prevent the entrance of contaminants into the well from surface or near-surface sources.

11.7.6 Hydraulic Fracturing. The hydraulic fracturing pressure shall be transmitted through a drill string and shall not be transmitted to the well casing. Hydraulic fracturing intervals shall be at least 20 feet below the bottom of the permanent casing of a well. All hydraulic fracturing equipment shall be thoroughly disinfected with a 100 part per million chlorine solution before insertion into the well. The driller shall include the appropriate hydraulic fracturing information on the well log including methods, materials, maximum pressures, location of packers, and initial or final yields. In no case shall hydrofacturing allow commingling of waters within the well bore. Clean sand or other material such as propping agents approved by the Division may be injected into the well to hold the fractures open when pressure is removed.

11.7.7 Static Water Level, Well Development, and Well Yield. To fulfill the requirements of Subsection R655-4-4 (4.5.2), new wells designed to produce water shall be developed to remove drill cuttings, drilling mud, or other materials introduced into the well during construction and to restore the natural groundwater flow to the well to the extent possible. After a water production well is developed, a test should be performed to determine the rate at which groundwater can be reliably produced from the well. Following development and testing, the static water level in the well should also be measured. Static water level, well development information, and well yield information shall be noted on the official submittal of the well log by the well driller.

11.7.8 Packers. Packers shall be of a material that will not impart taste, odor, toxic substances or bacterial contamination to the water in the well.

11.7.9 Screens. Screens must be constructed of corrosion-resistant material and sufficiently strong to withstand stresses encountered during and after installation. Screen slot openings, screen length, and screen diameter should be sized and designed to provide sufficient open area consistent with strength requirements to transmit sand-free water from the well. Screens should be installed so that exposure above pumping level will not occur.

11.7.10 Openings in the Casing. There shall be no opening in the casing wall between the top of the casing and the bottom of the required casing seal except for pitless adapters, measurement access ports, and other approved openings installed in conformance with these standards. In no case shall holes be cut in the casing wall for lifting or lowering casing into the well bore unless such holes are properly welded closed and watertight before placement into the well bore.

11.7.11 Casing vents. If a well requires venting, it must terminate in a down-turned position at least 18-inches above ground level, at or above the top of the casing or pitless unit and be covered with a 24 mesh corrosion-resistant screen.

Notes

Utah Admin. Code R655-4-11

Amended by Utah State Bulletin Number 2018-9, effective 4/9/2018 Adopted by Utah State Bulletin Number 2022-15, effective 7/26/2022