Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 8 - QUALITY STANDARDS FOR WYOMING GROUND WATERS
Section 8-5 - Classification for Groundwater of the State Affected by a Discharge; Classification by Aquifer and Area
Current through September 21, 2024
(a) Classification of Groundwaters of the State shall be based on the water quality standards of this chapter; excepting, a Class I Groundwater of the State shall be classified by ambient water quality and the technical practicability and economic reasonableness of treating ambient water quality to meet use suitability standards.
(b) Underground water quality shall be classified for an aquifer that is or may be affected by a subsurface discharge or other activity identified in Section 4.a. of these regulations.
(c) Classification shall be made:
(d) Classification shall be for a water in a specified locally defined area by named and described aquifer or receiver. Any aquifer or receiver in its regional setting may have one or more classifications by defined area or areas.
(e) The lateral and vertical limits of an aquifer or receiver, for purposes of classification, shall be based on existing water use, ambient water quality and geologic and hydrologic characteristics of the aquifer or of the receiver.
(f) An underground water may be reclassified if new or additional data warrant reclassification
TABLE I
| UNDERGROUND WATER CLASS | |||
| I | II | III | |
| Use Suitability Constituent or Parameter |
Domestic* Concentration** |
Agriculture Concent.** | Livestock Concent.** |
| Aluminum (Al) | --- | 5.0 | 5.0 |
| Ammonia (NH3-N) | 0.57 | --- | --- |
| Arsenic (As) | 0.05 | 0.1 | 0.2 |
| Barium (Ba) | 2.0 | --- | --- |
| Beryllium (Be) | --- | 0.1 | --- |
| Boron (B) | 0.75 | 0.75 | 5.0 |
| Cadmium (Cd) | 0.005 | 0.01 | 0.05 |
| Chloride (Cl) | 250.0 | 100.0 | 2000.0 |
| Chromium (Cr) | 0.10 | 0.1 | 0.05 |
| Cobalt (Co) | --- | 0.05 | 1.0 |
| Copper (Cu) | 1.0 | 0.2 | 0.5 |
| Cyanide (CN) | 0.2 | --- | --- |
| Fluoride (F) | 4.0 | --- | --- |
| Hydrogen Sulfide(H2S) | 0.05 | --- | --- |
| Iron (Fe) | 0.3 | 5.0 | --- |
| Lead (Pb) | 0.015 | 5.0 | 0.1 |
| Lithium (Li) | --- | 2.5 | --- |
| Manganese (Mn) | 0.05 | 0.2 | --- |
| Mercury (Hg) | 0.002 | --- | 0.00005 |
| Nickel (Ni) | --- | 0.2 | --- |
| Nitrate (NO3-N) | 10.0 | --- | --- |
| Nitrite (NO2-N) | 1.0 | --- | 10.0 |
| (NO3+NO2)-N | --- | --- | 100.0 |
| Oil & Grease | Virtually Free | 10.0 | 10.0 |
| Phenol | 0.001 | --- | --- |
| Selenium (Se) | 0.05 | 0.02 | 0.05 |
| Silver (Ag) | 0.10 | --- | --- |
| Sulfate (SO4) | 250.0 | 200.0 | 3000.0 |
| Total Dissolved Solids (TDS) | 500.0 | 2000.0 | 5000.0 |
| Vanadium (V) | --- | 0.1 | 0.1 |
| Zinc (Zn) | 5.0 | 2.0 | 25.0 |
| pH | 6.5-8.5 | 4.5-9.0s.u. | 6.5-8.5s.u |
| SAR | --- | 8.0 | --- |
| RSC | --- | 1.25 meq/L | --- |
| Combined Total Radium 226 and Radium 2288 | 5pCi/L | 5pCi/L | 5pCi/L |
| Total Strontium 90 | 8pCi/L | 8pCi/L | 8pCi/L |
|
Gross alpha particle radioactivity (including Radium 226 but excluding Radon and Uranium8 |
15pCi/L | 15pCi/L | 15pCi/L |
* This list does not include all constituents in the national drinking water standards.
** mg/L, unless otherwise indicated
TABLE I
| UNDERGROUND WATER CLASS | |
| Use Suitability Constituent or Parameter |
Special (A) Fish/Aquatic Life Concentration* |
| Aluminum (Al) | 0.1 |
| Ammonia (NH3) | 0.021 |
| Arsenic (As) | 0.05 |
| Barium (Ba) | 5.0 |
| Beryllium (Be) | 0.011-1.33 |
| Boron (B) | --- |
| Cadmium (Cd) | 0.0004-0.0153 |
| Chloride (Cl) | --- |
| Chromium (Cr) | 0.05 |
| Cobalt (Co) | --- |
| Copper (Cu) | 0.01-0.043 |
| Cyanide (CN) | 0.005 |
| Fluoride (F) | --- |
| Hydrogen Sulfide (H2S) | 0.0022 |
| Iron (Fe) | 0.5 |
| Lead (Pb) | 0.004-0.153 |
| Lithium (Li) | --- |
| Manganese (Mn) | 1.0 |
| Mercury (Hg) | 0.00005 |
| Nickel (Ni) | 0.05-0.43 |
| Nitrate (NO3-N) | --- |
| Nitrite (NO2-N) | --- |
| (NO3+NO2-N | --- |
| Oil & Grease | Virtually Free |
| Phenol | 0.001 |
| Selenium (Se) | 0.05 |
| Silver (Ag) | 0.0001-0.000253 |
| Sulfate (SO4) | --- |
| Total Dissolved Solids(TDS) | 500.04-1000.05-2000.06 |
| Uranium (U) | 0.03-1.43 |
| Vanadium (V) | --- |
| Zinc (Zn) | 0.05-0.63 |
| pH | 6.5-9.0 s.u. |
| Combined Total Radium 226 and Radium 2288 | 5 pCi/L |
| Total Strontium 90 | 8 pCi/L |
| Gross alpha particle radioactivity (including Radium 226 but excluding Radon and Uranium8 | 15pCi/L |
*mg/L, unless otherwise indicated
TABLE I
Explanation for Superscripts Used in Table I
1Unionized ammonia: When ammonia dissolves in water, some of the ammonia reacts with water to form ammonium ions. A chemical equilibrium is established that contains unionized ammonia (NH3), ionized ammonia (NH4+) and hydroxide ions (OH-).The toxicity of aqueous solutions of ammonia is attributed to NH3; therefore, the standard is for unionized ammonia. [Note: 0.02 mg/L NH3 is equivalent to 0.016 NH3 as (N)]
2 Undissociated H2S: The toxicity of sulfides derives primarily from H2S, rather than from the dissociated hydrosulfide (HS-) or sulfide (S2-) ions; therefore, the standard is for the toxic undissociated H2S.
3Dependent on hardness: The toxicity of metals in natural waters varies with the hardness of the water; generally, the limiting concentration is higher in hard water than in soft water.
4Egg hatching
5Fish rearing
6Fish and aquatic life
7Total ammonia nitrogen
8Requirements and procedures for the measurement and analysis of gross alpha particle activity, Radium 226 and Radium 228 shall be the same as requirements and procedures of the U.S. Environmental Protection Agency, National Interim Primary Drinking Water Regulations, EPA-570/9-76-003, effective June 24, 1977.
