R655-4-12. Special Wells

  12.1 Construction Standards for Special Wells.

  12.1.1 General. The construction standards outlined in Section R655-4-11 are meant to serve as minimum acceptable construction standards. Certain types of wells such as cathodic protection wells, closed-loop heating or cooling exchange wells, recharge and recovery wells, and public supply wells require special construction standards that are addressed in this section or in rules promulgated by other regulating agencies. At a minimum, when constructing special wells as listed above, the well shall be constructed by a licensed well driller, and the minimum construction standards of Section R655-4-11 shall be followed in addition to the following special standards.

  12.1.2 Public Water Supply Wells. Public water supply wells are subject to the minimum construction standards outlined in Section R655-4-11 in addition to the requirements established by the Department of Environmental Quality, Division of Drinking Water under Rules R309-515 and R309-600. Rules and requirements in R309-515 and R309-600 are regulated by the Division of Drinking Water and not by the Division of Water Rights and may include a preliminary evaluation report related to drinking water source protection, well plan and specification review and approval, and mandatory grout seal inspection (The Division of Drinking Water should be contacted to determine specific and current rules and requirements).

  12.1.3 Cathodic Protection Well Construction. Cathodic protection wells shall be constructed in accordance with the casing, joint, surface seal, and other applicable requirements outlined in Section R655-4-11. Any annular space existing between the base of the annular surface seal and the top of the anode and conductive fill interval shall be filled with appropriate fill or sealing material. Fill material shall consist of washed granular material such as sand, pea gravel, or sealing material. Fill material shall not be subject to decomposition or consolidation and shall be free of pollutants and contaminants. Fill material shall not be toxic or contain drill cuttings or drilling mud. Additional sealing material shall be placed below the minimum depth of the annular surface seal, as needed, to prevent the cross-connection and commingling of separate aquifers and water bearing zones. Vent pipes, anode access tubing, and any other tubular materials (i.e., the outermost casing) that pass through the interval to be filled and sealed are considered casing for the purposes of these standards and shall meet the requirements of Subsections R655-4-11.2 and 11.3. Cathodic protection well casing shall be at least 2 inches in internal diameter to facilitate eventual well abandonment. Figure 6 illustrates the construction of a typical cathodic protection well.

  12.1.4 Closed-loop Heating/Cooling Exchange Wells. Wells or boreholes utilized for heat exchange or thermal heating in a closed-loop fashion, which are greater than 30 feet in depth and encounter formations containing groundwater, must be drilled by a licensed driller and the owner or applicant must have an approved application for that specific purpose as outlined in Section R655-4-9. Wells or boreholes installed for heat or thermal exchange process must comply with the minimum construction standards of Section R655-4-11. Direct exchange (DX) systems are not allowed unless case by case permission is provided by the state engineer.

  12.1.4.1 For open-loop systems where groundwater is removed, processed, and re-injected, a non-consumptive use water right approval must be obtained from the state engineer. Approval to re-inject water underground is also required from the Utah Division of Water Quality. Open-loop system wells shall be constructed in accordance with the requirements found in Section 11. If a separate well or borehole is required for re-injection purposes, it must also comply with these standards and the groundwater must be injected into the same water bearing zones as from which it is initially withdrawn. The quality and quantity of groundwater shall not be diminished or degraded upon re-injection.

  12.1.4.2 Closed-loop heat exchange wells must also comply with the guidelines set forth in the National Ground Water Association Guidelines for Construction of Vertical Boreholes for Closed Loop Heat Pump Systems (guidelines are copyrighted and available from the National Ground Water Association at 601 Dempsey Rd, Westerville, OH 43081-8978, Phone [phone], Fax [phone], website www.ngwa.org, email [e-mail]) or standards set forth in the Design and Installation Standards for Closed-Loop/Geothermal Heat Pump Systems (standards are copyrighted and available from the International Ground Source Heat Pump Association (374 Cordell South, Oklahoma State University, Stillwater, OK 74078-8018, www.igshpa.okstate.edu). These guidelines and standards may be viewed during normal business hours at the Division's main office at 1594 West North Temple, SLC, UT 84116). For closed-loop systems where groundwater is not removed in the process, non-production well approval must be obtained from the state engineer. Specific requirements for closed-loop wells include:

  a. The location of closed loop heat pump wells must comply with applicable ordinances, regulations, or other enforceable instruments of local governments to ensure adequate protection of public water systems from encroachments or any impairment of the groundwater resource. During drilling and construction, provisions shall be made to reduce entry of foreign matter or surface runoff into the well or borehole.

  b. Closed-loop system wells must be sealed from the bottom of the well/boring to ground surface using acceptable materials and placement methods described in Section 11.4. Sand may be added to the seal mix to enhance thermal conductivity as long as the seal mix meets permeability and gel strength standards outlined in Section 11.4.

  c. Borehole Diameter: The borehole diameter of a closed loop heat pump well must be of sufficient size to allow placement of the pipe and placement of a tremie to emplace the grout. In general, for loop piping with a nominal diameter of 3/4 to 1 inch, the borehole diameter shall be at least 4.75 inches. For loop piping with a nominal diameter of 1.25 inches, the borehole diameter shall be at least 5.25 inches. For loop piping with a nominal diameter of 1.5 to 2.0 inches, the borehole diameter shall be at least 6.0 inches.

  d. Grouting of Vertical Ground Water Heat Pump Wells: Grouting the annulus of a heat pump well shall be completed within 24 hours from the time the borehole is drilled and loaded with the U-bend assembly and within at least 6 hours from the time the drill rig moves off the borehole. Full-length grout placement is required on all vertical closed loop heat pump boreholes.

  e. Placement of Grout Material: Full-length grout material must be placed by tremie from the bottom of the borehole to the top. The tremie pipe shall be continuously submerged in grout during placement. The tremie pipe must not be left in the borehole. The grout must fill the entire borehole. Grout must not be allowed to free-fall. Once the grout has settled for at least 48 hours, borehole shall be topped off with additional grout as necessary to maintain seal material to ground surface.

  f. Pipe: Pipe material, joining methods, and installation must meet the guidelines and standards referenced in the National Ground Water Association Guidelines for Construction of Vertical Boreholes for Closed Loop Heat Pump Systems, (guidelines are copyrighted and available from the National Ground Water Association at 601 Dempsey Rd, Westerville, OH 43081-8978, Phone [phone], Fax [phone], email [e-mail]) and in the Design and Installation Standards for Closed-Loop/Geothermal Heat Pump Systems (standards are copyrighted and available from the International Ground Source Heat Pump Association (374 Cordell South, Oklahoma State University, Stillwater, OK 74078-8018, www.igshpa.okstate.edu). Guidelines and standards may be viewed during normal business hours at the Division's main office at 1594 West North Temple, SLC, UT 84116). U-bend connections shall be factory jointed and piping shall not have any fusion joints below a depth of 30 feet.

  g. Pressure Testing: Loop piping shall be filled with water and pressure tested prior to installation into the borehole. Loop piping failing this initial pressure testing shall not be installed. The installed system must be pressure tested at a minimum of 2 times the system operating pressure to ensure the integrity of the system. If a pressure loss is detected, the cause must be properly repaired or material replaced or properly plugged. The system shall be pressure tested again following any repairs. Pressure testing procedures shall follow the guidelines and standards in the National Ground Water Association Guidelines for Construction of Vertical Boreholes for Closed Loop Heat Pump Systems, (guidelines are copyrighted and available from the National Ground Water Association at 601 Dempsey Rd, Westerville, OH 43081-8978, Phone [phone], Fax [phone], email [e-mail]) and in the Design and Installation Standards for Closed-Loop/Geothermal Heat Pump Systems (standards are copyrighted and available from the International Ground Source Heat Pump Association (374 Cordell South, Oklahoma State University, Stillwater, OK 74078-8018, www.igshpa.okstate.edu). Guidelines and standards may be viewed during normal business hours at the Division's main office at 1594 West North Temple, SLC, UT 84116).

  h. Heat transfer fluid, additives, and inhibitors. The heat transfer fluids, additives, and inhibitors used inside the closed-loop assembly must be nontoxic, safe to install, provide corrosion protection, not promote bacterial growth, and not produce an unacceptable risk to the environment in the event of a system leak. Potassium acetate or ethylene glycol shall not be used as a heat transfer fluid. Water used in the heat transfer fluid mix must be from a treated potable source or be disinfected in accordance with these rules. Use and placement of fluids, additives, and inhibitors shall be in accordance with the guidelines and standards in the National Ground Water Association Guidelines for Construction of Vertical Boreholes for Closed Loop Heat Pump Systems, (guidelines are copyrighted and available from the National Ground Water Association at 601 Dempsey Rd, Westerville, OH 43081-8978, Phone [phone], Fax [phone], email [e-mail]) and in the Design and Installation Standards for Closed-Loop/Geothermal Heat Pump Systems (standards are copyrighted and available from the International Ground Source Heat Pump Association (374 Cordell South, Oklahoma State University, Stillwater, OK 74078-8018, www.igshpa.okstate.edu). Guidelines and standards may be viewed during normal business hours at the Division's main office at 1594 West North Temple, SLC, UT 84116).

  i. Abandonment: When closed-loop heat exchange wells are required to be permanently abandoned (decommissioned and sealed), the most recent version of the standards referenced in the previous section shall be followed. The state engineer shall be notified prior to loop field abonnement. All heat transfer fluids shall be flushed and removed from loop piping prior to abandonment. Below ground loop piping to be abandoned shall be filled completely with acceptable grout and the loop piping ends properly capped or sealed.

  12.1.4.3 The rules herein pertain only to the heating and cooling exchange well constructed to a depth greater than 30 feet and are not intended to regulate the incidental work that may occur up to the well such as plumbing, electrical, piping, trenching, and backfilling activities.

  12.1.5 Recharge and Recovery Wells. Any well drilled under the provisions of Title 73, Chapter 3b (Groundwater Recharge and Recovery Act) shall be constructed in a manner consistent with these rules and shall be drilled by a currently licensed driller. Special rules regarding the injection of water into the ground are also promulgated under the jurisdiction of the Utah Department of Environmental Quality, Division of Water Quality (Rule R317-7 "Underground Injection Control Program" of the Utah Administrative Code) and must be followed in conjunction with the Water Well Drilling rules.