Classification Of Injection Wells

01. Classification of Injection Wells. For the purposes of these rules, injection wells are classified as follows: (3-18-22) a. Class I: (3-18-22) i. Wells used by generators of hazardous waste or owners or operators of hazardous waste management facilities to inject hazardous waste beneath the lowermost formation containing, within one-quarter (1/ 4) mile of the well bore, an underground source of drinking water. (3-18-22) ii. Other industrial and municipal disposal wells which inject fluids beneath the lowermost formation containing, within one-quarter (1/4) mile of the well bore, an underground source of drinking water. (3-18-22) iii. Radioactive waste disposal wells which inject fluids below the lowermost formation containing an underground source of drinking water within one-quarter (1/4) mile of the well bore. (3-18-22) b. Class II. Wells used to inject fluids: (3-18-22) i. Which are brought to the surface in connection with natural gas storage operations, or conventional oil or natural gas production and may be commingled with waste waters from gas plants, dehydration stations, or compressor stations which are an integral part of production operations, unless those waters are classified as a hazardous waste at the time of injection. (3-18-22) ii. For enhanced recovery of oil or natural gas; and (3-18-22) iii. For storage of hydrocarbons which are liquid at standard temperature and pressure. (3-18-22) c. Class III. Wells used to inject fluids for extraction of minerals including: (3-18-22) i. Mining of sulfur by the Frasch process; (3-18-22) ii. In situ production of uranium or other metals; this category includes only in-situ production from ore bodies which have not been conventionally mined. Solution mining of conventional mines such as stopes leaching is included in Class V. (3-18-22) iii. Solution mining of salts or potash. (3-18-22) d. Class IV: (3-18-22) i. Wells used by generators of hazardous waste or of radioactive waste, by owners or operators of IDAHO ADMINISTRATIVE CODE IDAPA 37.03.03 – Rules & Minimum Standards Department of Water Resources for the Construction & Use of Injection Wells Section 020 Page 8 hazardous waste management facilities, or by owners or operators of radioactive waste disposal sites to dispose of hazardous waste or radioactive waste into or above a formation which within one-quarter (1/4) mile of the well contains an underground source of drinking water. (7-1-25) ii. Wells used by generators of hazardous waste or owners or operators of hazardous waste management facilities to dispose of hazardous waste, which cannot be classified under Subparagraphs 020.01.a.i or 020.01.d.i. of this rule (e.g., wells used to dispose of hazardous waste into or above a formation which contains an aquifer which has been exempted pursuant to Section 025 of these rules). (7-1-25) e. Class V -- All injection wells not included in Classes I, II, III, IV, or VI. (3-18-22) f. Class VI. (3-18-22) i. Wells that are not experimental in nature that are used for geologic sequestration of carbon dioxide beneath the lowermost formation containing a USDW; or (3-18-22) ii. Wells used for geologic sequestration of carbon dioxide that have been granted a waiver of the injection depth requirements pursuant to requirements at 40 CFR Section 146.95; or (3-18-22) iii. Wells used for geologic sequestration of carbon dioxide that have received an expansion to the areal extent of an existing Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to Section 025 of these rules. (3-18-22) 02. Subclassification. Class V wells are subclassified as follows: (3-18-22) a. 5A5-Electric Power Generation. (3-18-22) b. 5A6-Geothermal Heat. (3-18-22) c. 5A7-Heat Pump Return. (3-18-22) d. 5A8-Aquaculture Return Flow. (3-18-22) e. 5A19-Cooling Water Return. (3-18-22) f. 5B22-Saline Water Intrusion Barrier. (3-18-22) g. 5D2-Storm Runoff. (3-18-22) h. 5D3-Improved Sinkholes. (3-18-22) i. 5D4-Industrial Storm Runoff. (3-18-22) j. 5F1-Agricultural Runoff Waste1. (7-1-25) k. 5G30-Special Drainage Water. (3-18-22) l. 5N241-Radioactive Waste Disposal1. (7-1-25) m. 5R21-Aquifer Recharge. (3-18-22) n. 5S23-Subsidence Control. (3-18-22) o. 5W9-Untreated Sewage1. (7-1-25) p. 5W10- Large Capacity Cesspools2. (7-1-25) IDAHO ADMINISTRATIVE CODE IDAPA 37.03.03 – Rules & Minimum Standards Department of Water Resources for the Construction & Use of Injection Wells Section 025 Page 9 q. 5W11-Septic Systems (General). (3-18-22) r. 5W12-Waste Water Treatment Plant Effluent. (3-18-22) s. 5W20-Industrial Process Water. (3-18-22) t. 5W31-Septic Systems (Well Disposal). (3-18-22) u. 5W32-Septic System (Drainfield). (3-18-22) v. 5X13-Mine Tailings Backfill. (3-18-22) w. 5X14-Solution Mining. (3-18-22) x. 5X15-In-Situ Fossil Fuel Recovery. (3-18-22) y. 5X16-Spent Brine Return Flow. (3-18-22) z. 5X25-Experimental Technology. (3-18-22) aa. 5X26-Aquifer Remediation. (3-18-22) bb. 5X27-Other Wells. (3-18-22) cc. 5X28-Motor Vehicle Waste Disposal Wells2. (7-1-25) dd. 5X29-Abandoned Water Wells. (3-18-22) 1 The construction of wells in this subclass is currently prohibited in Idaho. 2 The construction and operation of wells in these subclasses is currently prohibited in Idaho. 021. -- 024. (RESERVED)