R317-7-3. Classification of Injection Wells

Injection wells are classified as follows:

3.1 Class I

A. Hazardous Waste Injection Wells: wells used by generators of hazardous wastes or owners or operators of hazardous waste management facilities to inject hazardous waste beneath the lowermost formation containing, within two miles of the well bore, an underground source of drinking water;

B. Nonhazardous Injection Wells: other industrial and municipal waste disposal wells which inject nonhazardous fluids beneath the lowermost formation containing, within two miles of the well bore, an underground source of drinking water; this category includes disposal wells operated in conjunction with uranium mining activities.

C. Radioactive waste disposal wells which inject fluids below the lowermost formation containing an underground source of drinking water within two miles of the well bore.

3.2 Class II. Wells which inject fluids:

A. which are brought to the surface in connection with conventional oil or natural gas production and may be commingled with wastewaters from gas plants which are an integral part of production operations, unless those waters are classified as a hazardous waste at the time of injection;

B. for enhanced recovery of oil or natural gas; and

C. for storage of hydrocarbons which are liquid at standard temperature and pressure.

Class II injection wells are regulated by the Division of Oil, Gas and Mining under Oil and Gas Conservation General Rules, R649-5.

3.3 Class III. Wells which inject for extraction of minerals, including:

A. mining of sulfur by the Frasch process;

B. 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; and

C. solution mining of salts or potash.

3.4 Class IV

A. Wells used by generators of hazardous wastes or of radioactive wastes, by owners or operators of hazardous waste management facilities, or by owners or operators of radioactive waste disposal sites to dispose of hazardous wastes or radioactive wastes into a formation which, within two miles of the well, contains an underground source of drinking water;

B. wells used by generators of hazardous wastes or of radioactive wastes, by owners or operators of hazardous waste management facilities, or by owners or operators of radioactive waste disposal sites to dispose of hazardous wastes or radioactive wastes above a formation which, within two miles of the well, contains an underground source of drinking water;

C. wells used by generators of hazardous wastes or by owners or operators of hazardous waste management facilities, to dispose of hazardous wastes which cannot be classified under Section 7-3.1(A) or 7-3.4(A) and (B) of these rules (e.g. wells used to dispose of hazardous wastes into or above a formation which contains an aquifer which has been exempted).

3.5 Class V. Injection wells not included in Classes I, II, III, or IV. Class V wells include:

A. air conditioning return flow wells used to return to the supply aquifer the water used for heating or cooling in a heat pump;

B. large capacity cesspools, including multiple dwelling, community or regional cesspools, or other devices that receive untreated sanitary wastes, containing human excreta, which have an open bottom and sometimes have perforated sides. The UIC requirements do not apply to single family residential cesspools nor to non-residential cesspools which receive solely sanitary wastes and have a design flow rate of less than or equal to 5,000 gallons per day;

C. cooling water return flow wells used to inject water previously used for cooling;

D. drainage wells used to drain surface fluid, primarily storm runoff, into a subsurface formation;

E. dry wells used for the injection of wastes into a subsurface formation;

F. recharge wells used to replenish the water in an aquifer;

G. salt water intrusion barrier wells used to inject water into a fresh water aquifer to prevent the intrusion of salt water into the fresh water;

H. sand backfill and other backfill wells used to inject a mixture of water and sand, mill tailings or other solids into mined out portions of subsurface mines, whether what is injected is radioactive waste or not;

I. large underground domestic wastewater disposal systems (as defined in R317-1-1.16) used to inject effluent from a domestic wastewater treatment system associated with a multiple family dwelling, business establishment, community, or regional business establishment. The UIC requirements do not apply to single family residential onsite wastewater systems (as defined in R317-1-1.13), nor to non-residential onsite wastewater systems which are used solely for the disposal of treated domestic waste and have a design flow rate of less than or equal to 5,000 gallons per day. Any subsurface fluid distribution system or other type of injection well designed for any flow rate and used to dispose of industrial wastewater is not an underground wastewater disposal system as defined by R317-1-1.32.

J. subsidence control wells (not used for the purpose of oil or natural gas production) used to inject fluids into a non-oil or gas producing zone to reduce or eliminate subsidence associated with the overdraft of fresh water;

K. stopes leaching, geothermal and experimental wells;

L. brine disposal wells for halogen recovery processes;

M. injection wells associated with the recovery of geothermal energy for heating, aquaculture and production of electric power; and

N. injection wells used for in situ recovery of lignite, coal, tar sands, and oil shale.

O. motor vehicle waste disposal wells that receive or have received fluids from vehicular repair or maintenance activities, such as an auto body repair shop, automotive repair shop, new and used car dealership, specialty repair shop (e.g., transmission and muffler repair shop), or any facility that does any vehicular repair work. Fluids disposed in these wells may contain organic and inorganic chemicals in concentrations that exceed the maximum contaminant levels (MCLs) established by the primary drinking water rules (see 40 CFR Part 141 and Utah Primary Drinking Water Standards R309-200-5). These fluids also may include waste petroleum products and may contain contaminants, such as heavy metals and volatile organic compounds, which pose risks to human health.