Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 8 - QUALITY STANDARDS FOR WYOMING GROUND WATERS
Section 8-4 - Quality Standards Prescribed; Groundwaters of the State Classified
Universal Citation: WY Code of Rules 8-4
Current through September 21, 2024
(a) Standards are prescribed to protect the natural quality of underground water:
(i) Receiving pollution or wastes directly
from a subsurface discharge or by migrating water or fluid of a
discharge;
(ii) Invaded by
underground water of inferior quality as a result of well or exploration hole
drilling or completion practices;
(iii) From pollution that may result from
above-ground facilities capable of causing or contributing to
pollution;
(iv) From pollution that
may result from surface mining operations.
(b) Groundwaters of the State are classified in order to apply standards to protect water quality. Groundwaters of the State are classified by use, and by ambient water quality.
(c) Waters that are known sources of supply and appropriated for uses identified in W.S. 35-11-102 and 103(c)(i) are classified herein as: Domestic water; Water for fish and aquatic life; Water for agriculture; Water for livestock; and, Water for industry. A discharge or activity that impacts an underground source of water for existing uses identified in W.S. 35-11-102 and 103(c)(i) shall not make the affected water unsuitable for its intended use or uses, at any place or places of withdrawal or natural flow to the surface.
(d) Unappropriated waters are classified by ambient water quality.
(i) Class I
Groundwater of the State - This water is suitable for domestic use. The ambient
quality of underground water of this suitability does not have a concentration
in excess of any of the standards for Class I Groundwater of the State (see
Table I, page 9).
(ii) Class II
Groundwater of the State - This water is suitable for agricultural use where
soil conditions and other factors are adequate. The ambient quality of
underground water of this suitability does not have a concentration in excess
of any of the standards for Class II Groundwater of the State (see Table I,
page 9).
(iii) Class III
Groundwater of the State - This water is suitable for livestock. The ambient
quality of underground water of this suitability does not have a concentration
in excess of any of the standards for Class III Groundwater of the State (see
Table I, page 9).
(iv) Class
Special (A) Groundwater of the State -This water is suitable for fish and
aquatic life. The ambient quality of underground water of this suitability does
not have a concentration in excess of any of the standards for Class Special
(A) Groundwater of the State (see Table I, page 10).
(v) Underground water of Class I, II, III or
Special (A)
(A) Shall not contain biological,
hazardous, toxic or potentially toxic materials or substances in concentrations
or amounts that exceed maximum allowable concentrations based upon information
of the EPA in the Federal Register for December 24, 1975 (Part IV), Water
Programs, National Interim Primary Drinking Water Regulations; and in the
Federal Register for March 13, 1978 (Part II), Water Programs, Hazardous
Substances. In addition, underground water of Class I, II, III or Special (A)
shall not contain any biological, hazardous, toxic or potentially toxic
materials or substances in concentrations or amounts that, based upon the
latest available scientific information and as determined by the Administrator,
will impair this water for its use suitability or that may contribute to a
condition in contravention of groundwater quality standards or to any toxic or
hazardous effect on natural biota.
(vi) A discharge into an aquifer containing
Class I, II, III or Special (A)
(A)
Groundwater of the State shall not result in variations in the range of any
parameter, or concentrations of constituents in excess of the standards of
these regulations at any place or places of withdrawal or natural flow to the
surface. A discharge that results in concentrations in excess of standards
shall be permitted if post-discharge water quality can be returned to a quality
of use equal to, or better than, and consistent with the uses for which the
water was suitable prior to the operation.
(vii) Class IV Groundwater of the State -
This water is suitable for industry. The quality requirements for industrial
water supplies range widely and almost every industrial application has its own
standards.
(A) Class IV (A) Groundwater of
the State has a total dissolved solids concentration not in excess of 10,000
mg/L.
(B) Class IV (B) Groundwater
of the State has a total dissolved solids concentration in excess of 10,000
mg/L.
(C) A discharge into an
aquifer containing Class IV (A) or IV (B) Groundwater of the State shall not
result in the water being unfit for its intended use.
(D) A discharge into an aquifer with Class IV
(A) or IV (B) Groundwater of the State shall not result in oil and grease
concentrations in excess of 10 mg/L or a lesser amount if a concentration in
excess of the lesser amount is determined to be toxic; or oil and grease in
excess of background concentrations of the underground water, whichever is
greater, at any place or places of withdrawal or natural flow to the
surface.
(E) A discharge into an
aquifer with Class IV (A) or IV (B) Groundwater of the State shall not result
in radioactivity concentrations or amounts that exceed the standards for Class
I through III and Special (A) Groundwaters of the State; or in concentrations
or amounts that exceed background concentrations of the underground water,
whichever is greater, at any place or places of withdrawal or natural flow to
the surface.
(F) A discharge into
an aquifer with Class IV (A) or IV (B) Groundwater of the State shall not
result in biological, hazardous, toxic or potentially toxic materials or
substances including pesticides, insecticides or herbicides in concentrations
or amounts that exceed maximum allowable concentrations, based upon information
of the EPA in the Federal Register for December 24, 1975 (Part IV),
Water Programs, National Interim Primary Drinking Water
Regulations, and in the Federal Register for March 13, 1978 (Part II), Water
Programs, Hazardous Substances; or that exceed background
concentrations of the underground water, whichever is greater, at any place or
places of withdrawal or natural flow to the surface.
In addition, a discharge shall not result in any biological, hazardous, toxic or potentially toxic materials or substances, in concentrations or amounts that, based on the latest available scientific information and as determined by the Administrator, will impair the quality of ambient Groundwaters of the State of this class; or that may contribute to a condition in contravention of groundwater quality standards or cause, allow or permit any deleterious effect on natural biota.
(viii) Groundwater of the State found closely
associated with commercial deposits of hydrocarbons and/or other minerals, or
that is considered a geothermal resource, is Class V (Hydrocarbon Commercial),
Class V (Mineral Commercial) or Class V (Geothermal) Groundwater of the State.
(A) A discharge into a Class V (Hydrocarbon
Commercial) Groundwater of the State shall be for the purpose of the production
of oil and gas and shall not result in the degradation or pollution or waste of
other water resources.
(B) A
discharge into a Class V (Mineral Commercial) Groundwater of the State shall be
for the purpose of mineral production and shall not result in the degradation
or pollution of the associated or other groundwater and, at a minimum, be
returned to a condition and quality consistent with the pre-discharge use
suitability of the water.
(C) A
discharge into a Class V (Geothermal) Groundwater of the State shall be for the
purpose of the production of geothermal resources and shall not result in the
degradation or pollution or waste of other water resources.
(ix) Class VI Groundwater of the
State may be unusable or unsuitable for use:
(A) Due to excessive concentration of total
dissolved solids or specific constituents; or
(B) Is so contaminated that it would be
economically or technologically impractical to make the water useable;
or
(C) Is located in such a way,
including depth below the surface, so as to make use economically and
technologically impractical.
Disclaimer: These regulations may not be the most recent version. Wyoming may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google
Privacy Policy and
Terms of Service apply.
