Definitions (Rule 10)

01. Approved Seal or Seal Material. Seal material must consist of bentonite chips, pellets, or granules, bentonite grout, neat cement, or neat cement grout as defined by these rules. (7-1-25) 02. Annular Space. The space, measured as one-half (1/2) the difference in diameter between two (2) concentric cylindrical objects, one of which surrounds the other, such as the space between the walls of a drilled hole (borehole) and a casing or the space between two (2) strings of casing. (3-18-22) 03. Aquifer. Any geologic formation(s) that will yield water to a well in sufficient quantities to make the production of water from the formation feasible for beneficial use. (3-18-22) 04. Area of Drilling Concern. An area designated by the Director in which drillers must comply with additional standards to prevent waste or contamination of ground or surface water due to such factors as aquifer pressure, vertical depth of the aquifer, warm or hot ground water, or contaminated ground or surface waters, in accordance with Section 42-238(15), Idaho Code. (7-1-25) 05. Artesian Water. Any water that is confined in an aquifer under pressure so that the water will rise in the well casing or drilled hole above the elevation where it was first encountered. This term includes water of flowing and non-flowing wells. (3-18-22) 06. Artificial Filter Pack. Clean, rounded, smooth, uniform, sand or gravel placed in the annular space around a perforated well casing or well screen. A filter pack is frequently used to prevent the movement of finer material into the well casing and to increase well efficiency. (3-18-22) 07. Bentonite. A commercially processed and packaged, low permeability, sodium montmorillonite clay certified by the NSF International for use in well construction, sealing, plugging, and decommissioning. All bentonite products used in the construction or decommissioning of wells must have a permeability rating not greater than 10-7 (ten to the minus seven) cm/sec. (7-1-25) a. Chips. Bentonite composed of pieces ranging in size from one-quarter (1/4)-inch to one (1) inch on their greatest dimension. (3-18-22) b. Granules (also Granular). Bentonite composed of pieces ranging in size from one thirty-seconds (1/ 32) inch (#20 standard mesh) to seven thirty-seconds (7/32) inch (#3 standard mesh) on their greatest dimension. (3-18-22) c. Bentonite Grout. A mixture of bentonite specifically manufactured for use as a well sealing or plugging material and potable water to produce a grout with an active solids content not less than twenty-five percent (25%) by weight e.g., (twenty-five percent (25%) solids content by weight = fifty (50) pounds bentonite per eighteen (18) gallons of water). (3-18-22) d. Pellets (also Tablets). High swelling sodium bentonite compressed into pellet form, including pellets coated with a time release biodegradable coating. (7-1-25) 08. Board. The Idaho Water Resource Board. (3-18-22) 09. Bore Diameter. The diameter of the hole in the formation made by the drill bit or reamer. IDAHO ADMINISTRATIVE CODE IDAPA 37.03.09 Department of Water Resources Well Construction Standards Rules Section 010 Page 4 (3-18-22) 10. Borehole (also Well Bore and Boring). The subsurface hole created during the drilling process. (7-1-25) 11. Bottom Hole Temperature. The temperature of the ground water encountered in the bottom of a well or borehole. (7-1-25) 12. Casing. The permanent steel or thermoplastic pipe installed in a well to maintain the well opening and serve as a solid inner barrier to allow for the installation of an annular seal. (7-1-25) 13. Cathodic Protection Well. Any artificial excavation more than eighteen (18) feet in vertical depth constructed for the purpose of protecting certain metallic equipment in contact with the ground. Commonly referred to as cathodic protection. (7-1-25) 14. Closed Loop Heat Exchange Well. A well through which thermal exchange fluids are circulated but remain isolated from direct contact with the subsurface or ground water. (7-1-25) 15. Conductor Pipe. The first and largest diameter string of permanent casing installed in a well when multiple casing strings are necessary. (7-1-25) 16. Confining Layer. A subsurface zone of low-permeability earth material that naturally acts to restrict or retard the movement of water or contaminants from one zone to another. (7-1-25) 17. Consolidated Formations. Naturally-occurring geologic formations that have been lithified (turned to stone) such as sandstone and limestone, or igneous rocks such as basalt and rhyolite, and metamorphic rocks such as gneiss and slate. (3-18-22) 18. Contaminant. Any physical, chemical, biological, or radiological substance or matter. (7-1-25) 19. Contamination. The introduction into the natural ground water of any physical, chemical, biological or radioactive material that may: (3-18-22) a. Cause a violation of Standards found in IDAPA 58.01.11, “Ground Water Quality Rule,” or primary federal drinking water regulation found in 40 CFR Parts 141 and 142 whichever is more stringent.; or (7-1-25) b. Adversely affect the health of the public; or (3-18-22) c. Adversely affect a designated or beneficial use of the State’s ground water. Contamination includes the introduction of heated or cooled water into the subsurface that will alter the ground water temperature and render the local ground water less suitable for beneficial use. (7-1-25) 20. Decommissioned (Abandoned) Well. Any well that has been permanently removed from service and filled or plugged in accordance with these rules to meet the intent of these rules. A properly decommissioned well will not: (7-1-25) a. Produce or accept fluids; (3-18-22) b. Serve as a conduit for the movement of contaminants inside or outside the well casing; or (3-18-22) c. Allow the movement of surface or ground water into unsaturated zones, into another aquifer, or between aquifers. (3-18-22) 21. Decontamination. The process of removing contaminants from equipment intended for use in a well. (7-1-25) IDAHO ADMINISTRATIVE CODE IDAPA 37.03.09 Department of Water Resources Well Construction Standards Rules Section 010 Page 5 22. Department. The Idaho Department of Water Resources. (3-18-22) 23. Dewatering Well. A well constructed for the purpose of improving slope stability, drying up land, or intercepting seepage that would otherwise enter an excavation. (7-1-25) 24. Director. The Director of the Idaho Department of Water Resources. (7-1-25) 25. Disinfection. The introduction of chlorine or other agent or process approved by the Director in sufficient concentration and for the time required to inactivate or kill fecal and Coliform bacteria, indicator organisms, and other pathogens. (7-1-25) 26. Draw Down. The difference in vertical distance between the static water level and the pumping water level. (3-18-22) 27. Drive Point (also known as a Sand Point). A conduit through which ground water of any temperature is sought or encountered; created by joining a “drive point unit” to a length of pipe and driving the assembly into the ground. (7-1-25) 28. Geotechnical Borings. Borings drilled for the sole purpose of obtaining soil samples or other data to determine subsurface geologic properties. (7-1-25) 29. Hydraulic Fracturing. A process whereby water or other fluid is pumped under high pressure into a well to further fracture the reservoir rock or aquifer surrounding the production zone of a well to increase well yield. (3-18-22) 30. Injection Well. Any feature that is operated to allow the subsurface emplacement of fluids that also meets at least one (1) of the following criteria: (7-1-25) a. A bored, or driven shaft whose depth is greater than the largest surface dimension; (7-1-25) b. A dug hole whose depth is greater than the largest surface dimension; (7-1-25) c. An improved sinkhole; or (7-1-25) d. A subsurface fluid distribution system. (7-1-25) 31. Intermediate String or Casing. Casing installed and sealed to isolate undesirable water or zones below first string of permanent casing. Such strings may either be lapped into the casing above it or extend to land surface. (7-1-25) 32. Liner. A removable steel or thermoplastic pipe used as access and protective housing for pumping equipment and provide a pathway for the upward flow of water within the well. (7-1-25) 33. Modify. To deepen a well, increase or decrease the diameter of the casing or the well bore, install a liner, place a screen, perforate existing casing or liner, alter the seal between the casing and well bore, or alter the well to not meet well construction standards. (3-18-22) 34. Monitoring Well. Any well used to evaluate, observe or determine the quality, quantity, temperature, pressure or other characteristics of the ground water or aquifer. (7-1-25) 35. Neat Cement. A mixture of water and cement in the ratio of not more than six (6) gallons of water to ninety-four (94) pounds of Portland cement. Other neat cement mixes may be used if specifically approved by the Director. (7-1-25) 36. Neat Cement Grout. Up to five percent (5%) bentonite by dry weight may be added per sack of cement and the water increased to not more than six and one-half (6.5) gallons per sack of cement. Other neat cement grout mixes may be used if specifically approved by the Director. These grouts must be mixed and installed in IDAHO ADMINISTRATIVE CODE IDAPA 37.03.09 Department of Water Resources Well Construction Standards Rules Section 010 Page 6 accordance with the American Petroleum Institute Standards - API Class A through H. As found in API RP10B, “Recommended Practice for Testing Oil Well Cements and Cement Additives,” current edition or other approved standards. (7-1-25) 37. Oxidized Sediments. Sediments, characterized by distinct coloration, typically shades of brown, red, or tan, caused by the alteration of certain minerals in an environment with a relative abundance of oxygen. (3-18-22) 38. Perforated Well Casing. Well casing that has been modified by the addition of openings created by drilling, torch cutting, saw cutting, mechanical down-hole perforator, or other method. (3-18-22) 39. Pitless Adaptor or Pitless Unit. An assembly that provides a watertight connection between the pump installed inside the well casing and buried pipe outside the well casing. (7-1-25) 40. Potable Water. Water of adequate quality for human consumption. (3-18-22) 41. Pressure Grouting (Grouting). The process of pumping and placing an approved grout mixture into the required annular space, well bore, casing or screens by positive displacement from bottom to top using a tremie pipe, Halliburton method, float shoe, or other method approved by the Director. (7-1-25) 42. Production Casing. The final string of casing or tubing extending from the producing zone to land surface. (7-1-25) 43. Public Drinking Water System. A system for the provision to the public of water for human consumption through pipes or, after August 5, 1998, other constructed conveyances, if such system has at least fifteen (15) service connections, regardless of the number of water sources or configuration of the distribution system, or regularly serves an average of at least twenty-five (25) individuals daily at least sixty (60) days out of the year. Such term includes: any collection, treatment, storage, and distribution facilities under the control of the operator of such system and used primarily in connection with such system; and any collection or pretreatment storage facilities not under such control which are used primarily in connection with such system. Such term does not include any “special irrigation district.” A public drinking water system is either a “community water system” or a “noncommunity water system” as further defined as: (7-1-25) a. Community water system. A public drinking water system which serves at least fifteen (15) service connections used by year-round residents or regularly serves at least twenty-five (25) year-round residents. (7-1-25) b. Noncommunity water system. A public drinking water system that is not a community water system. A non-community water system is either a transient noncommunity water system or a non-transient noncommunity water system. (7-1-25) c. Nontransient noncommunity water system. A public drinking water system that is not a community water system and that regularly serves at least twenty-five (25) of the same persons over six (6) months per year. (7-1-25) d. Transient noncommunity public drinking water system. A noncommunity water system which does not regularly serve at least twenty-five (25) of the same persons over six (6) months per year. (7-1-25) 44. Reduced Sediments. Sediments, characterized by distinct coloration, typically shades of blue, black, gray, or green, caused by the alteration of certain minerals in an oxygen poor environment. (3-18-22) 45. Remediation Well. A well used to inject or withdraw fluids, vapor, or other solutions approved by the Director for the purposes of remediating, enhancing quality, or controlling potential or known contamination. Remediation wells include those used for air sparging, vapor extraction, or injection of chemicals for remediation or in-situ treatment of contaminated sites. (3-18-22) 46. Sand. Any sediment particle retained on a U.S. standard sieve #200 (Seventy-five hundreths (0.075) mm to two (2) mm). (3-18-22) IDAHO ADMINISTRATIVE CODE IDAPA 37.03.09 Department of Water Resources Well Construction Standards Rules Section 010 Page 7 47. Screen (Well Screen). A commercially produced structural tubular retainer with standard sized openings to facilitate production of sand free water. (3-18-22) 48. Seal or Sealing. The placement of approved seal material in the required annular space between a borehole and casing, between casing strings, or as otherwise required to create a low permeability barrier and prevent movement or exchange of fluids. (7-1-25) 49. Start Card. An expedited drilling permit process for the construction of cold water, single-family residential wells. (3-18-22) 50. Static Water Level. The depth to water in a well under non-pumping conditions. (7-1-25) 51. Surface Casing. The first string of casing in a low temperature geothermal resource well which is set and sealed after the conductor pipe to anchor blow out prevention equipment and to case and seal out all existing cold ground water zones. (3-18-22) 52. Temporary Casing. Steel pipe used to support the borehole within unstable or unconsolidated formations during construction of a well that will be removed following the installation of the permanent well casing and prior to or during placement of an annular seal. (7-1-25) 53. Thermoplastic/PVC Casing. Plastic piping material meeting the requirements of ASTM F 480 and NSF-WC and specifically designed for use as well casing. (7-1-25) 54. Transmissivity. The capacity of an aquifer to transmit water through its entire saturated thickness. (3-18-22) 55. Tremie Pipe. A small-diameter pipe used to convey grout, dry bentonite products, or filter pack materials into the annular space, borehole, or well from the bottom to the top of a borehole or well. (3-18-22) 56. Unconfined Aquifer. An aquifer in which the water table is in contact with and influenced by atmospheric pressure through pore spaces in the overlying formation(s). (3-18-22) 57. Unconsolidated Formation. A naturally-occurring earth formation that has not been lithified. Alluvium, soil, sand, gravel, clay, and overburden are some of the terms used to describe this type of formation. (3-18-22) 58. Unstable Unit. Unconsolidated formations, and those portions of consolidated formations, that are not sufficiently hard or durable enough to sustain an open borehole without caving or producing obstructions without the aid of fluid hydraulics or other means of chemical or physical stabilization. (3-18-22) 59. Unusable Well. Any well that can not be used for its intended purpose or other beneficial use authorized by law. (3-18-22) 60. Waiver. Approval in writing by the Director of a written request from the well driller and the well owner proposing specific variance from the minimum well construction standards. (3-18-22) 61. Waste. The loss, transfer, or subsurface exchange of a ground water resource, thermal characteristic, or natural artesian pressure from any aquifer caused by improper construction, misuse, or failure to properly maintain a well. Waste includes: (3-18-22) a. The flow of water from an aquifer into an unsaturated subsurface zone; (3-18-22) b. The transfer or mixing, or both, of waters from one aquifer to another (aquifer commingling); or (3-18-22) c. The release of ground water to the land surface whenever such release does not comply with an IDAHO ADMINISTRATIVE CODE IDAPA 37.03.09 Department of Water Resources Well Construction Standards Rules Section 025 Page 8 authorized beneficial use. (3-18-22) 62. Water Table. The upper surface of the zone of saturation in an unconfined aquifer. This level will change over time due to changes in water supply and aquifer impacts. (7-1-25) 63. Well. An artificial excavation or opening in the ground more than eighteen (18) feet in vertical depth below land surface by which ground water of any temperature is sought or obtained. Any water encountered in the well is considered to be obtained for the purpose of these rules. (7-1-25) 64. Well Development. The act of bailing, jetting, pumping, or surging water in a well to remove drilling fluids, fines, and suspended materials from within a completed well and production zone to establish the optimal hydraulic connection between the well and the aquifer. (7-1-25) 65. Well Driller or Driller. Any person who operates drilling equipment, or who controls or supervises the construction of a well, and is licensed under Section 42-238, Idaho Code (3-18-22) 66. Well Drilling or Drilling. The act of constructing a new well or modifying the construction of an existing well. (7-1-25) 67. Well Owner. Any person, firm, partnership, co-partnership, corporation, association, or other entity, or any combination of these, who owns the property on which the well is or will be located or has secured ownership of the well by means of a deed, covenant, contract, easement, or other enforceable legal instrument for the purpose of benefiting from the well. (3-18-22) 68. Well Rig (Drill Rig). Any power driven percussion, rotary, boring, digging, jetting, auguring, or any other power-driven mechanical equipment used in the drilling of a well. (7-1-25) 011. -- 024. (RESERVED)