Idaho Administrative Code
Title IDAPA 37 - Water Resources, Department of
Rule 37.03.09 - WELL CONSTRUCTION STANDARDS RULES
Section 37.03.09.025 - CONSTRUCTION OF COLD WATER WELLS
Current through August 31, 2023
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. (3-18-22)
01. General. The well driller must construct each well as follows: (3-18-22)
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. |
(3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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. |
(3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
09. Sealing Artesian Wells. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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: (3-18-22)
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: (3-18-22)
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. (3-18-22)
16. Decommissioning (Abandoning) of Wells. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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. (3-18-22)
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 ¼ cups |
3 tbsp |
8 |
261 |
4 cups |
5 tbsp |
10 |
408 |
6 ¼ cups |
½ cup |
12 |
588 |
9 cups |
¾ cup |
16 |
1044 |
1 gal |
1 ¼ 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 |
(3-18-22)
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). (3-18-22)
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. (3-18-22)