Idaho Admin. Code r. 37.03.09.025

Current through September 2, 2024

Section 37.03.09.025 - CONSTRUCTION OF COLD WATER WELLS

All persons constructing wells must comply with the requirements of Section 42-238, Idaho Code, and IDAPA 37.03.10, "Well Driller Licensing Rules." The standards specified in Rule 25 apply to all wells with a bottom hole temperature of eighty-five (85) degrees Fahrenheit or less. Wells with a bottom hole temperature greater than eighty-five (85) degrees Fahrenheit, but less than two hundred twelve (212) degrees Fahrenheit, must meet the requirements of Rule 30 in addition to meeting the requirements of Rule 25. These standards also apply to any waste disposal and injection well as defined in Section 42-3902, Idaho Code.

01.General. The well driller must construct each well as follows:

a. In accordance with these rules and with the conditions of approval of any drilling permit issued pursuant Section 42-235, Idaho Code, and in a manner that will prevent waste and contamination of the ground water resources of the state of Idaho. The adopted standards are minimum standards which must be adhered to in the construction of all new wells, and in the modification or decommissioning (abandonment) of existing wells. The well driller is charged with the responsibility of preventing waste or contamination of the ground water resources during the construction, modification or abandonment of a well. The Director may add conditions of approval to a drilling permit issued pursuant to Rule 45 of these rules to require that a well be constructed, modified, or decommissioned (abandoned) in accordance with additional standards when necessary to protect ground water resources and the public health and safety from existing contamination and waste or contamination during the construction, modification or decommissioning (abandonment) of a well.

b. In consideration of the geologic and ground water conditions known to exist or anticipated at the well site.

c. Such that it is capable of producing, where obtainable, the quantity of water to support the allowed or approved beneficial use of the well, subject to law;

d. Meet the siting and separation distance requirements in the table in this Subsection (025.01 .d.). Additional siting and separation distance requirements are set forth by the governing district health department and the Idaho Department of Environmental Quality rules at IDAPA 58.01.03, "Individual/Subsurface Sewage Disposal Rules," and IDAPA 58.01.08, "Idaho Rules for Public Drinking Water Systems".

Separation of Well from:	Minimum Separation Distance (feet)
Existing Public Water Supply well, separate ownership	- 50
Other existing well, separate ownership	- 25
Septic drain field	- 100
Septic tank	- 50
Drainfield of system with more than 2,500 GPD of sewage inflow	- 300*
Sewer line - main line or sub-main, pressurized, from multiple sources	- 100
Sewer line - main line or sub-main, gravity, from multiple sources	- 50
Sewer line - secondary, pressure tested, from a single residence or building	- 25
Effluent pipe	- 50
Property line	- 5
Permanent buildings, other than those to house the well or plumbing apparatus, or both	- 10
Above ground chemical storage tanks	- 20
Permanent (more than six months) or intermittent (more than two months) surface water	- 50
Canals, irrigation ditches or laterals, & other temporary (less than two months) surface water	- 25
*This distance may be less if data from a site investigation demonstrates compliance with IDAPA 58.01.03, "Individual/Subsurface Sewage Disposal Rules," separation distances.

02.Waivers. In unique cases where the Director concludes that the ground water resources will be protected against waste and contamination and the public health and safety are not compromised, a waiver of specific standards required by these rules may be approved prior to constructing, decommissioning, or modifying a well.

a. To request a waiver the well driller and well owner must:

i. Jointly submit a detailed plan and written request identifying a specific Rule or Rules proposed to be waived. Additionally, the plan must detail the well construction process that will be employed in lieu of complete Rule compliance:

ii. Prior to submittal, the well driller and the well owner must sign the plan and written request acknowledging concurrence with the request; and

iii. Submit the plan and request by facsimile, e-mail, or letter.

b. The Director will evaluate and respond to the request within ten (10) business days of receiving the request.

i. If the request for waiver is approved, the intent of the rules will be served and all standards not waived will apply. Waivers approved by the Director will not supersede requirements of other regulatory agencies without specific concurrence from that agency. Work activity related to a waiver request will not proceed until a written or verbal approval is granted by the Director.

ii. Any verbal approval will be followed by a written approval.

03.Records. In order to enable a comprehensive survey of the extent and occurrence of the state's ground water resource, the coordinates of every newly constructed, modified or decommissioned (abandoned) well location must be identified by latitude and longitude with a global positioning system (GPS) and recorded on the driller's report in degrees and decimal minutes and within the nearest 40 acre parcel using the Public Land Survey System. Every well driller must maintain records as described in IDAPA 37.03.10 "Well Driller Licensing Rules," pursuant to Section 42-238(11), Idaho Code, and provide the well owner with a copy of the approved well drilling permit and a copy of the well driller's report when submitted to the Director.

04.Casing. The well driller must install casing in every well. Steel or thermoplastic casing may be installed in any well with a bottom hole temperature of eighty-five (85) degrees Fahrenheit or less. Thermoplastic pipe must not be installed in a well with a bottom hole temperature greater than eighty-five (85) degrees Fahrenheit. All casing to be installed must be new or in like-new condition, free of defects, and clearly marked by the manufacturer with all specifications required by these rules. For all wells the casing must extend at least twelve (12) inches above land surface and finished grade and to a minimum depth below land surface as required by these rules. Concrete slabs around a well casing will be considered finished grade (Figure 01, Appendix A). The well driller must install casing of sufficient strength to withstand calculated and anticipated subsurface forces and corrosive effects. The well driller must install casings sufficiently plumb and straight to allow the installation or removal of screens, liners, pumps and pump columns without causing adverse effects on the operation of the installed pumping equipment.

a. Steel Casing. When steel casing lengths are joined together, they must be joined by welded joints or screw-couple joints. All connection must be water tight. If steel casing joints are welded, the weld must be at least as thick as the well casing and fully penetrating. Welding rods or flux core wire of at least equal quality to the casing metal must be used. Casing ends to be joined by welding must be properly prepared, beveled and gapped to allow full penetration of the weld. All stick welded joints must have a minimum of two (2) passes including a "root" pass and have minimal undercut when complete.

i. In addition to meeting these standards, all wells that are constructed for public water systems must meet all of the casing wall thickness requirements set forth by the Idaho Department of Environmental Quality Rules, IDAPA 58.01.08, "Idaho Rules for Public Drinking Water Systems."

ii. The well driller must install steel casing that meets or exceeds the American Society of Testing and Materials (ASTM) standard A53, Grade B or American Petroleum Institute (API) 5L Grade B, and that meets the following specifications for wall thickness:

Minimum Single-Wall Steel Well Casing Thickness1 for Selected Diameters (inches)
Nominal Diameter (in.)3	62	8	10	12	14	16	18	20	22	24	26	28	30
Depth (ft.)	Nominal Wall Thickness (in.)1
<100	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250
100-200	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250
200-300	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250
300-400	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.375	0.375	0.375	0.375
400-600	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.250	0.375	0.375	0.375	0.375	0.375
600-800	0.250	0.250	0.250	0.250	0.250	0.250	0.375	0.375	0.375	0.375	0.375	0.375	0.375
800-1000	0.250	0.250	0.250	0.250	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375
1000-1500	0.280	0.322	0.365	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375
1500-2000	0.280	0.322	0.365	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375	0.375
1 Compliance with the minimum nominal wall thicknesses listed is required for any depth or location where casing is used to prevent caving or collapse, or both, of the borehole or serves as a solid inner barrier to allow for the installation of an annular seal. 2 For nominal casing diameters less than six (6) inches, the minimum nominal wall thickness must be equivalent to ASTM Schedule 40. 3 For any other casing diameter not addressed herein, prior approval by the Director is required.

b. Thermoplastic Casing. Thermoplastic casing may be used in monitoring wells and cold water wells if drilling of the borehole confirms its suitability for use.

i. Thermoplastic casing must conform to ASTM F 480 and NSF-WC. The well driller must not use thermoplastic casing under any condition where the manufacturer's resistance to hydraulic collapse pressure (RHCP) or total depth specifications are exceeded. Thermoplastic casing extending above-ground must be protected from physical and ultraviolet light damage by enclosing it within steel casing extending at least twelve (12) inches above land surface and finished grade and to a minimum depth of eighteen (18) feet below land surface or five (5) feet below land surface for monitoring wells.

ii. Thermoplastic pipe used in wells as casing or liner must have a minimum rating of SDR-21. For nominal diameters of four (4) inches or less, a minimum rating of Schedule 40 is required. If used as casing within unconsolidated or unstable consolidated formations, thermoplastic pipe must be centralized and fully supported throughout the unstable zone(s) with filter pack or seal material as required by these rules.

iii. All thermoplastic casing and liner must be installed in accordance with the manufacturer's recommendations and specifications, and as required by these rules. The well driller will not treat thermoplastic pipe in any manner that would adversely affect its structural integrity. The well driller must:

(1) Ensure that the weight of the pump assembly, if secured to the thermoplastic pipe, does not exceed the weight limitations per manufacturer's recommendations or cause damage to the pipe resulting in breaks or leaks.

(2) Not use Type III (high-early strength) Portland cement-based seal materials in direct contact with thermoplastic pipe unless approved by the Director.

(3) Not drive, drop, force, or jack thermoplastic pipe into place. Thermoplastic pipe must be lowered or floated into an oversized, obstruction-free borehole.

c. Perforated Well Casing. Perforated well casing may be used in the construction or decommissioning of a well when such application does not violate any standards required by these rules.

05.Liner. In addition to well casing, liners may be installed in wells to prevent damage to pumping equipment. Steel or thermoplastic pipe may be installed as liner in a well with a bottom hole temperature of eighty-five (85) degrees Fahrenheit or less. Thermoplastic liner must conform to ASTM F 480 and NSF-WC. Thermoplastic liners must not be used in unconsolidated formations or unstable units.

06.Screen. Well screens must be used in constructing a well when necessary to avoid sand production (see sand production, Rule 25, Subsection 025.24). Well screens must be commercially manufactured, be slotted, louvered or wire wrapped, and be installed according the manufacturers specifications.

a. Screens may require a filter pack consisting of sand or gravel to further reduce the quantity of sand produced from the well.

b. The well driller will not install well screens, perforated casing or filter pack across a confining layer(s) separating aquifers of different pressure, temperature, or quality.

07.Use of Approved Sealing Materials and Required Annular Space. Well casings must be sealed in the required annular space with approved material to prevent the possible downward movement of contaminated surface waters or other fluids in any annular space around the well casing (Figure 02, Appendix A). Proper sealing is also required to prevent the movement of groundwater either upward or downward from zones of different pressure, temperature or quality within the well or outside the casing. The well driller must notify by phone the Department's appropriate Region Office at least four (4) hours in advance of placing any annular seal to provide Department staff the opportunity to observe seal placement.

a. All casing to be sealed must be adequately centralized to ensure uniform seal thickness around the well casing. Surface seals must extend to not less than thirty-eight (38) feet below land surface for well depths greater than thirty-eight (38) feet. For well depths less than thirty-eight (38) feet, seals must extend to depths as hereafter required.

b. Seals are required at depths greater than thirty-eight (38) feet in artesian wells or to seal through confining layers separating aquifers of differing pressure, temperature, or quality in any well.

c. When a well is modified and the existing casing is moved or the original seal is damaged, or a well driller discovers that a seal was not installed or has been damaged, the well driller must repair, replace, or install a seal around the permanent casing that is equal to or better than required when the well was originally constructed.

d. Manufactured packers and shale traps may be used as devices to retain approved seal material when installing a required annular seal. Whenever these devices are used to retain seal material, the well driller must comply with the manufacturer's recommendations for installation.

e. If a temporary casing has been installed, upon completion of the drilling, the annular space must be filled with approved seal material and kept full while withdrawing the temporary casing. Bentonite chips should be used with caution when the annular space between a temporary casing and permanent casing is filled with water.

i. When attempts at removing a temporary casing are unsuccessful, the casing must be sealed in place by a method approved by the department.

ii. The well driller must notify the department whenever a temporary casing can not be removed and propose a plan to adequately seal the casing to prevent waste and contamination of the ground water. The plan must detail how the casing will be sealed on the outside to a sufficient depth below land surface in addition to placement of any required formation seals through the interval at which the casing will remain.

f. For mixed grout seals the minimum annular space required must provide for a uniform seal thickness not less than one (1) inch on all sides of the casing or a borehole at least two (2) inches larger than the outside diameter (OD) of the casing to be sealed (Figure 02, Appendix A). (Note: a seven and seven-eighths (7 7/8) inch diameter (eight (8) inch nominal) borehole around a six and five-eighths (6 5/8) inch OD (six (6) inch nominal casing does not satisfy the minimum annular space requirements).

i. When placing grout seals with a removable tremie pipe between casing strings or between a borehole and casing, the required annular space must be at least one (1) inch or equal to the OD of the tremie pipe whichever is greater. Permanent tremie pipes will be considered as a casing string and subject to minimum annular space requirements in addition to the annular space requirements around the well casing (Figure 03, Appendix A).

ii. All grout seals must be placed from the bottom up, by using an approved method. Bentonite grout must not be used above the water table unless specifically designed and manufactured for such use and approved by the Director in advance.

iii. If cement-based grout (neat cement or neat cement grout) is used to create a seal, the casing string sealed must not be moved or driven after the initial set. Construction must not resume for a minimum of twenty-four (24) hours following seal placement;

g. For dry bentonite seals the minimum annular space required must provide for a uniform seal thickness not less than one and five-eighths (1 5/8) inches on all sides of the casing or a borehole at least four (4) inches larger than the "nominal diameter" of the casing to be sealed. e.g., (six and five-eighths (6 5/8) inch OD (six (6) inch nominal) casing requires a ten and three fourths (10 3/4) inch OD (ten (10) inch nominal) temporary casing or a nine and seven-eighths (9 7/8) inch (ten (10) inch nominal) minimum borehole). Listed below are additional annular space requirements and limitations for placement of dry bentonite seals:

i. All dry bentonite seals must be tagged during placement and consider volumetric calculations to verify placement.

ii. Installation of dry bentonite seals must be consistent with the manufacturers' recommendations and specifications for application and placement.

iii. Granular bentonite must not be placed through water.

iv. If a granular bentonite seal is placed deeper than two hundred (200) feet, the minimum annular space must be increased by at least one (1) inch e.g., (six and five-eighths (6 5/8) inch OD (six (6) inch nominal) casing requires a twelve and three fourths (12 3/4) inch OD (twelve (12) inch nominal) temporary casing or an eleven and seven eights (11 7/8) inch (twelve (12) inch nominal) minimum borehole).

v. Bentonite chips may be placed through water or drilling fluid of appropriate viscosity. Bentonite chip seals placed through more than fifty (50) feet of water or drilling fluid will require the minimum annular space to be increased by at least one (1) inch e.g., (six and five-eighths (6 5/8) inch OD (six (6) inch nominal) casing requires a twelve and three fourths (12 3/4) inch OD (twelve (12) inch nominal) temporary casing or an eleven and seven eights (11 7/8) inch (twelve (12) inch nominal) minimum borehole).

08.Sealing of Wells. Sealing requirements described herein are minimum standards that apply to all wells. The Director may establish alternate minimum sealing requirements in specific areas when it can be determined through detailed studies of the local hydrogeology that a specific alternate minimum will provide protection of the ground water from waste and contamination.

a. Consolidated Formations. When a water well is drilled into and acquires water from an aquifer that consists of consolidated formations that are above the water table, casing must be installed so that it extends and is sealed to a depth not less than thirty-eight (38) feet (Figure 04, Appendix A). If the well depth is less than thirty-eight (38) feet from land surface, well casing must be installed and sealed five (5) feet into the consolidated formation or to a depth of eighteen (18) feet, whichever is greater.

b. Unconsolidated Formations without Confining Layers of Clay. When a water well is drilled into and acquires water from an unconfined aquifer that is overlain with unconsolidated formations, such as sand and gravel without confining layers of clay, well casing must extend to at least five (5) feet below the water table and be sealed to a depth not less than thirty-eight (38) feet (Figure 05, Appendix A). If the well depth is less than thirty-eight (38) feet well casing must extend to at least five (5) feet below the water table or eighteen (18) feet, whichever is greater, and be sealed to a depth of at least eighteen (18) feet.

i. The extensive (for example, one hundred fifty (150) feet thick or more) unconsolidated, non-stratified, sand and gravel of the Rathdrum Prairie are characterized by extremely high transmissivity and hydraulic conductivity. Under these conditions, sealing wells to depths greater than eighteen (18) feet may not be additionally protective. When a water well is drilled within the boundaries of the Rathdrum Prairie, (shown in Figure 06, Appendix A of these rules), well casing must extend to at least five (5) feet below the water table and be sealed to a depth not less than eighteen (18) feet (Figure 07, Appendix A).

c. Unconsolidated Formations with Confining Layers of Clay. When a well is drilled into and acquires water from an aquifer that is overlain by unconsolidated deposits such as sand and gravel, and there are confining layers of clay above the water table, well casing must be installed from the land surface to the confining layer immediately above and in contact with the production zone and sealed to a depth not less than thirty-eight (38) feet (Figure 08, Appendix A). If the well depth is less than thirty-eight (38) feet from land surface, well casing must extend and be sealed into the first confining layer or to a depth of eighteen (18) feet, whichever is greater.

09.Sealing Artesian Wells.

a. Unconsolidated Formations. When artesian water is encountered in unconsolidated formations, the production zone or open interval must be limited to zones of like pressure, temperature, and quality. Water encountered in oxidized sediments must not be comingled with water encountered in reduced sediments. Well casing must extend from land surface into the lower most confining layer above the production zone, and must be sealed:

i. From land surface to a depth of at least thirty-eight (38) feet; and

ii. Through all confining layer(s); and

(1) A minimum of five (5) feet of seal material must be placed into or through the lower most confining layer above the production zone (Figure 09, Appendix A); or

(2) Five (5) feet into or through the lowermost confining layer above the production zone and continuously to land surface (Figure 09, Appendix A).

iii. If the well depth is less than thirty-eight (38) feet, the well must be cased and sealed from land surface to the confining layer in direct contact with the production zone or to a depth of eighteen (18) feet, whichever is greater.

b. Consolidated Formations. When artesian water is encountered in a consolidated formation, well casing must be installed and sealed from land surface to a depth of at least thirty-eight (38) feet; and

i. If the consolidated formation is overlain by a permeable formation(s) and water will rise above the consolidated formation, well casing must extend and be sealed at least five (5) feet into the confining portion of the consolidated formation (Figure 10, Appendix A).

ii. If the well depth is less than thirty-eight (38) feet, the well must be cased and sealed from land surface five (5) feet into the confining consolidated formation or to a depth of eighteen (18) feet, whichever is greater.

c. Control Device. Pursuant to Section 42-1603, Idaho Code, if the well flows at land surface, it must be equipped with a control device approved by the Director, so that the flow can be completely stopped. If leaks occur around the well casing or adjacent to the well, the well must be completed with seals, casing or cement grout to eliminate the leakage.

i. Flowing artesian wells must be equipped with an approved pressure gage fitting that will allow access for measurement of shut-in pressure of a flowing well. All pressure gage fittings must include control valves such that the pressure gage can be removed without resulting in artesian flow from the well.

ii. The well driller must not move his well drilling rig from the site until all requirements have been satisfied. Some mixing of water may be allowed to develop an adequate water well; however, the mixing must be restricted to water zones of similar pressure, temperature and quality. The driller must take precautions to case and seal out zones which may lead to waste or contamination.

10.Alternative Methods for Sealing Wells. To accommodate for new technology, and in consideration of the wide variety of drilling equipment used to construct wells, other methods of sealing wells not specifically addressed in these rules may be allowed. The Director may consider specific proposals for alternative methods of sealing on a case by case basis. Director approval or acceptance of such procedures will not constitute a "waiver" of any requirements of these rules. In such cases, the well driller must provide sufficient information for the Director to determine that the full intent of the sealing requirements will be satisfied if an alternative method is employed. If it is determined that a specific alternate method will provide protection of the ground water from waste and contamination, the Director may issue a statement of acceptance qualifying the use and implementation of such methods.

11.Injection Wells. In addition to meeting the requirements of Rule 25 of these rules, the construction, modification, or decommissioning (abandonment) of all injection wells over eighteen (18) feet in vertical depth must also comply with the IDAPA 37.03.03, "Rules for the Construction and Use of Injection Wells," and the injection well permit. Drillers must obtain from the Director a certified copy of the permit authorizing construction or modification of an injection well before beginning work.

12.Cathodic Protection Wells. All cathodic protection wells must be constructed by a licensed well driller in compliance with these rules. A detailed construction plan must be included with the drilling permit application.

13.Monitoring and Remediation Wells. All monitoring wells and remediation wells must be constructed and maintained in a manner that will prevent waste or contamination and as otherwise required by these rules. When a monitoring well or a remediation well is no longer useful or needed, the owner or operator of the well must decommission (abandon) the well in accordance with Rule 25, Subsection 025.16 of these rules. No person may divert ground water from a monitoring well or a remediation well for any purpose not authorized by the Director. The application for a permit for all monitoring wells and all remediation wells must include a design proposal prepared by a licensed engineer or registered geologist pursuant to Section 42-235, Idaho Code. Blanket permits for monitoring well and remediation well networks may be approved for site-specific monitoring and remediation programs. The designs and specification for monitoring wells and remediation wells must demonstrate that:

a. The ground water resources are protected against waste and contamination;

b. The well(s) will inject or withdraw only fluids, gases or solutions approved by the Director;

c. The well(s) will be constructed so as to prevent aquifer commingling; and

d. The well(s) will be properly decommissioned (abandoned) upon project completion and in accordance with these rules.

14.Closed Loop Heat Exchange Wells. The well driller must construct closed loop heat exchange wells consistent with these rules. The well driller is not required to install steel casing in such wells. When constructing a closed loop heat exchange well, the well driller must:

a. Construct each borehole of sufficient size to provide the annular space required by these rules.

b. Seal the annular space of each borehole with approved seal material in accordance with these rules;

c. Install fluid-tight circulating pipe, composed of high-density polyethylene, grade PE3408, minimum cell classifications PE355434C or PE345434C conforming to ASTM Standard D3350, or other Director-approved pipe;

d. Join pipe using thermal fusion techniques according to ASTM Standards D-3261 or D-2683. All personnel creating such system joints must be trained in the appropriate thermal fusion technologies;

e. Use only propylene glycol, or other circulating fluid approved by the Director;

f. Ensure that any other system additive is NSF approved and has prior approval from the Director;

g. Pressure test each loop with potable water prior to grout installation;

h. Pressure test the system with potable water prior to installation of the circulating fluid at one hundred percent (100%) of the designed system operating pressure for a minimum duration of twenty-four (24) hours; and

i. Properly repair or decommission (abandon) all loops failing the test by pressure pumping approved seal material through the entire length of each failed loop. After grouting, loop ends must be fused together or capped.

15.Access Port or Pressure Gage. Upon completion of a well and before removal of the well rig from the site, the well must be equipped with an access port that will allow for measurement of the depth to water or an approved pressure gage fitting that will allow access for measurement of shut-in pressure of an artesian flowing well. All pressure gage fittings must include control valves such that the pressure gage can be removed. Approved access ports are illustrated in Figure 11, APPENDIX A, together with approved locations for pressure gage fittings. Air lines are not a satisfactory substitution for an access port. Nonflowing domestic and stock water wells that are to be equipped with a sanitary seal with a built-in access port are exempt from this requirement.

16.Decommissioning (Abandoning) of Wells.

a. The well owner is charged with maintaining and properly decommissioning (abandoning) a well in a manner that will prevent waste or contamination, or both, of the ground water. No person is allowed to decommission a well in Idaho without first obtaining a driller's license or receiving a waiver of the license requirement from the Director of the Department of Water Resources. Authorization is required from the Director prior to decommissioning any well. Upon decommissioning, the person who decommissioned the well must submit to the Director a report describing the procedure.

b. The Director may require decommissioning of a well in compliance with the provisions of these rules, if the well:

i. Does not meet minimum well construction standards;

ii. Meets the definition of an unusable well;

iii. Poses a threat to human health and safety;

iv. Is in violation of IDAPA 58.01.11, "Ground Water Quality Rule"; or

v. Has no valid water right or other authorization acceptable to the Director for use of the well.

c. When required by the Director, decommissioning must be done in accordance with the following:

i.Cased wells and boreholes without a continuous seal from the top of the intakes or screen to the surface. The well driller must use one (1) of the following methods as applicable:

(1) The Director may require that well casing be perforated every five (5) feet from the bottom of the casing to within five (5) feet of the surface. Perforations made must be adequate to allow the free flow of seal material into any voids outside the well casing. There must be at least four equally spaced perforations per section circumference. Approved grout must be pressure pumped to fill any voids outside of the casing. A sufficient volume must be used to completely fill the well and annular space; or

(2) Fill the borehole with approved seal material as the casing is being removed.

ii. Cased wells and boreholes with full-depth seals. If the well is cased and sealed from the top of the screen or production zone to the land surface, the well must be completely filled with approved seal material.

iii. Uncased wells must be completely filled with approved seal material.

iv. Dry hole wells or wells from which the quantity of water to meet a beneficial use cannot be obtained must be decommissioned with cement grout, concrete or other approved seal material in accordance with these rules.

17.Completion of a Well. The Director will consider that every well is completed when the well drilling equipment has been removed, unless written notice has been given to the Director by the well driller that he intends to return and do additional work on the well within a specified period of time. Upon completion of the well, the well must meet all of the required standards.

a. Upon completion of drilling and prior to removal of well drilling equipment from a water well site, the top of the casing must be completely covered with:

i. A one-fourth inch (1/4") thick solid, new or like-new steel plate with a three-fourths inch (3/4) threaded and plugged access port, welded to and completely covering the casing (Figure 12, Appendix A); or

ii. A threaded cap, or a commercially manufactured watertight sanitary well cap (Figure 12, Appendix A); or

iii. A commercially manufactured water-tight, snorkel-vented or non-vented well cap on any well susceptible to submergence; or

iv. A control device approved by the Director per Section 42-1603, Idaho Code, on any well that flows at land surface (Figure 11, Appendix A).

b. Upon the completion of every well, the well driller must permanently affix the stainless steel well tag to the steel surface casing in a manner and location that maintains tag legibility. For closed loop heat exchange wells, the well driller must obtain approval for the well tag placement and method of attachment. The well driller must secure each tag by:

i. A full-length weld across the top and down each side of the tag; or

ii. Using one (1) stainless steel, closed-end domed rivet near each of the four (4) corners of the tag.

iii. Prior to welding or riveting, the tag must be pre-shaped to fit the casing such that both sides to be welded or riveted touch the casing and no gaps exist between the tag and casing.

18.Pitless Adapters. When a pitless adaptor is used (Figure 12, Appendix A), the adaptor should be of the type approved by the NSF International testing laboratory or the approval code adopted by the Pitless Adaptor Division of the Water Systems Council. The pitless adaptor, including the cap or cover, casing extension, and other attachments, must be so designed and constructed to be water tight and to prevent contamination of the potable water supply from external sources. If a permanent surface or outer casing is installed and is cut off or breached to install the pitless adapter on an inner well casing or liner, the space between the permanent outer casing and the liner or inner casing must be sealed. The well owner or person installing the pitless adaptor must then seal the excavation surrounding the pitless adaptor using an approved seal material.

19.Pump Installation. No person is allowed to install a pump into any well that would cause a violation of Rule 25, of these rules or other applicable rules or state law.

20.Explosives. Explosives used in well construction must never be detonated inside the required well casing. Approved explosive casing perforators may be exempted by the Director.

21.Hydraulic Fracturing. Hydraulic fracturing must be performed only by well drillers licensed in Idaho. The pressure must be transmitted through a drill string and must not be transmitted to the well casing. The driller must provide a report to the Director of the fracturing work which must include well location, fracturing depth, fracturing pressures and other data as requested by the Director.

22.Drilling Fluids or Drilling Additives. The well driller must use only potable water and drilling fluids or drilling additives that are manufactured for use in water wells, are NSF International, American Petroleum Institute (API), or ASTM/ANSI approved; and do not contain a concentration of any substance in excess of Primary Drinking Water Standards, as set forth in IDAPA 58.01.08, "Rules for Public Drinking Water Systems," according to manufacturer's specifications. The well driller may seek approval from the Director to use specific, non-certified products on a case-by-case basis. In addition, the well driller must ensure the containment of all drilling fluids and materials used or produced to the immediate drilling site, and will not dispose of such fluids or materials into any streams, canals, boreholes, wells, or other subsurface pathways.

23.Disinfection and Decontamination. Upon completion of a well, the driller is responsible for adding the appropriate amount of disinfecting chemical compound and distributing it throughout the well to achieve a uniform concentration for "in place" disinfection of the well. Chlorine compounds used in accordance with the table listed below will satisfy this requirement. Other methods may be used if approved by the Director in advance.

Amount of Chlorine Needed Per 100 Feet of Water in Well
Casing Diameter (in.)	Gallons of water in casing per 100 ft. of water depth	Amount of 5.25% Sodium Hypochlorite (Unscented Laundry Bleach)	Amount of 65% Calcium Hypochlorite (Chlorine Granules)
6	147	2 1/4 cups	3 tbsp
8	261	4 cups	5 tbsp
10	408	6 1/4 cups	1/2 cup
12	588	9 cups	3/4 cup
16	1044	1 gal	1 1/4 cup
Note: 1 gal = 4 qt = 8 pt = 16 cups; 1 cup = 16 tbsp
Chlorine granules or tablets must be dissolved and placed into the well as a solution.
If another concentration of hypochlorite solution is used, the following equation should be used for calculating amounts. (Volume of water in gallons) X (0.08) / % Hypochlorite (e.g. 50% = 50) = cups of hypochlorite Example: To treat 147 gallons of water using a 50% concentration of hypochlorite solution: (147 gallons water) X (0.08) / 50 = .23 (or approximately 1/4) cup of 50% Hypochlorite solution

24.Sand Production. The maximum sand content produced from a well after initial well development must not exceed fifteen (15) ppm. For the purpose of this rule, sand is considered to be any sediment particle retained on a U.S. standard sieve #200 (seventy-five hundreths (0.075) mm to two (2) mm).

a. When necessary to mitigate sand production the well driller must:

i. Construct each well with properly sized casing, screen(s) or perforated intake(s); and

ii. Install properly sized filter pack(s); or

iii. Install pre-packed well screens; or

iv. Employ other methods approved by the Director.

b. The Director may grant a waiver exempting a well producing water that exceeds the maximum sand content only if the well driller has met the requirements of Rule 25, Subsection 025.24.a.

c. Sand production in public water system wells. Wells used in connection with a public water system have more stringent requirements. See IDAPA 58.01.08, "Idaho Rules for Public Water Systems."

25.Well Development and Testing. For each well the well driller must measure and record the static (non-pumping) water level and the pumping water level, and the production rate. The production rate will be determined by a pump, bailer, air-lift, or other industry approved test of sufficient duration to establish production from the well. For wells with no returns the driller must report no returns and the static water level. This information must be documented on the well driller's report.

Idaho Admin. Code r. 37.03.09.025

Effective March 18, 2022