SECTION 785:45-7-3. Groundwater classifications, beneficial uses and vulnerability levels

(a)   Classifications. Classification of all groundwater shall be designated as follows:

(1)   (Class I): [RESERVED] (Special Source Groundwater):

(2)   General Use Groundwater (Class II): These are groundwaters which have good quality due to natural conditions and generally have a mean concentration of Total Dissolved Solids of less than 3,000 milligrams per liter.

(3)   Limited Use Groundwater (Class III): These are groundwaters which have poor quality due to natural conditions and generally have a mean concentration of Total Dissolved Solids of greater than or equal to 3000 milligrams per liter but less than 5000 milligrams per liter.

(4)   Highly Mineralized Treatable Groundwater (Class IV): These are groundwaters which have very poor quality due to natural conditions and generally have a mean concentration of Total Dissolved Solids of greater than or equal to 5000 milligrams per liter but less than 10,000 milligrams per liter.

(b)   Beneficial uses. This subsection lists the various beneficial uses of groundwater and designates certain beneficial uses for certain classifications of groundwater.

(1)   List of beneficial uses for groundwater.

(A)   Public Water Supply. The beneficial use designation of Public Water Supply refers to those groundwaters capable of delivering suitable quantities of groundwater for municipal consumption whether or not treatment is required.

(B)   Domestic Untreated Water Supply. The beneficial use designation of Domestic Untreated Water Supply refers to those groundwaters capable of delivering suitable quantities of untreated groundwater for domestic consumption.

(C)   Agriculture. The beneficial use designation of Agriculture refers to that groundwater which is or could be used for irrigation or livestock watering.

(D)   Industrial and Municipal Process and Cooling Water. The beneficial use designation of Industrial and Municipal Process and Cooling Water refers to that groundwater that is or could be used for a municipal or industrial process or cooling function.

(2)   Beneficial use designations.

(A)   The beneficial uses for General Use Groundwater (Class II), not identified in Appendix H of this Chapter, shall be Domestic Untreated Water Supply, Public Water Supply, Agriculture, and Industrial and Municipal Process and Cooling Water.

(B)   The beneficial uses for Limited Use Groundwater (Class III) and Highly Mineralized Treatable Groundwater (Class IV), not identified in Appendix H of this Chapter, shall be Agriculture and Industrial and Municipal Process and Cooling Water.

(C)   The beneficial uses for any groundwater identified in Appendix H of this Chapter shall be as designated in that appendix.

(D)   The beneficial use for groundwater which is used for water supply purposes on or after July 1, 2000, has a mean concentration of Total Dissolved Solids of less than 5000 milligrams per liter, and has not been determined by any state environmental agency to be not suitable for human consumption, shall be Public Water Supply and or Domestic Untreated Water Supply.

(E)   A beneficial use designation for groundwater may be amended or removed only after a demonstration to the satisfaction of the Board that meets one of the following tests:

(i)   The designated use does not exist due to a condition that was not caused by humans, and treatment using Best Available Technology will not achieve the designated use, or

(ii)   The designated use does not exist due to a condition that is attributable to irreversible impacts caused by humans, and the remedy would cause substantial and widespread economic and social impact.

(F)   Groundwater which has had a beneficial use designation amended or removed pursuant to (E) of this paragraph shall be identified in Appendix H of this Chapter.

(c)   Vulnerability level. Groundwater in certain hydrogeologic basins is further classified according to its vulnerability to contamination as determined by DRASTIC. Such vulnerability levels of hydrogeologic basins shall be identified as Very Low, Low, Moderate, High, and Very High as prescribed in Table 1 of Appendix D of this Chapter. The vulnerability level may vary within each hydrogeologic basin, depending on site-specific hydrogeologic factors.

(d)   Nutrient-vulnerable groundwater. Certain specified groundwaters shall be further subject to designation in Table 2 of Appendix D of this Chapter as nutrient-vulnerable groundwater.

[Source: Amended at 9 Ok Reg 1889, eff 5-26-92; Amended at 16 Ok Reg 3240, eff 7-12-99; Amended at 17 Ok Reg 2766, eff 7-1-00; Amended at 19 Ok Reg 2511, eff 7-1-02; Amended at 34 Ok Reg 2170, eff 9-11-17]