Surface Water Quality Standards
Enforcement Actions
Electronic Documents Submittal
Recent General Permit Authorizations
Rules and Regulations
Surface Water Quality Standards
The Wyoming Department of Environmental Quality manages surface water quality through the implementation of Wyoming’s Surface Water Quality Standards (Chapter 1, Wyoming Water Quality Rules). Water quality standards consist of three core elements:
- Designated Uses – Identifies the intended management goals for the waterbody such as supporting aquatic life, drinking water, recreation, human consumption of fish, industry, irrigation, livestock, and other uses
- Water Quality Criteria – The level of water quality necessary to support designated uses (numeric pollutant concentrations and narrative requirements)
- Antidegradation – Protections for existing uses, high-quality waters, and unique Outstanding Resource Waters
Together, these three elements of water quality standards provide the framework for achieving Wyoming Environmental Quality Act and federal Clean Water Act goals and protecting, enhancing, and conserving Wyoming’s water resources. Water quality standards are implemented through:
- Development of water-quality-based effluent limitations for regulated point source discharges to surface waters in Wyoming Pollutant Discharge Elimination System (WYPDES) Program permits and 401 Water Quality Certifications;
- Reporting on the quality of Wyoming’s waters via Water Quality Assessment;
- Setting restoration goals (e.g., total maximum daily loads) for waters not meeting water quality standards.
Learn more about Wyoming’s Surface Water Quality Standards by clicking the links below.
Current Standards and Implementation Methods, and Tools
Wyoming Surface Water Quality Standards (Chapter 1, Wyoming Water Quality Rules), Updated August 6, 2025, available from the Secretary of State at rules.wyo.gov.
Wyoming Surface Water Designations Available in the “Standards Resources and Guidance” tab above and updated August 6, 2025. Use this document to identify designated uses that apply to a specific waterbody.
Recreation Designated Uses Web Map Updated August 6, 2025. Use this interactive map to identify recreation designated uses for a specific waterbody
Antidegradation Implementation Methods, Coming soon to the “Standards Resources and Guidance” tab above
Colorado River Basin Salinity Standards updated October 2023. These are adopted through the Colorado River Basin Salinity Control Forum and are applicable to surface waters within the Green River and Little Snake River subbasins of the Colorado River Basin in Wyoming. These salinity standards are incorporated by reference in Wyoming’s Surface Water Quality Standards.
Water Quality Criteria Calculator Available in the “Standards Resources and Guidance” tab above and updated August 19, 2025. Use this to calculate site-dependent aquatic life criteria for dissolved metals, ammonia-N, and pentachlorophenol, and to estimate undissociated hydrogen sulfide.
Water Quality Standards Summary Available in the “Standards Resources and Guidance” tab above and updated August 25, 2025. Basic summary of Wyoming Surface Water Quality Standards.
Modifications to Standards
Active Rulemaking and Triennial Review
Triennial Review – The federal Clean Water Act requires states to hold a public hearing and review water quality standards at least once every three years – commonly referred to as the Triennial Review. The review involves an evaluation of existing standards, considering new scientific information, and incorporating public input to determine if revisions or modifications to the standards are needed. The general process of a Triennial Review can be found here. Wyoming DEQ completed its current triennial review with the August 6, 2025, adoption of revisions to Wyoming’s Surface Water Quality Standards (Chapter 1, Wyoming Water Quality Rules) into state law and codified in Wyoming Administrative Code as 020.0011.1.08062025.
The Triennial Review Stakeholder Workgroup is a group of volunteers representing various stakeholders and perspectives on water quality standards that are considered when water quality standards are being reviewed or developed as part of a Triennial Review. They meet as needed and meetings are open to the public. If you have additional perspectives to share, please work through a Workgroup member. For more information contact Eric Hargett (eric.hargett@wyo.gov) or 307-777-7079.
Nutrient Pollution
- Efforts to Address Nutrient Pollution in Wyoming’s surface waters
Eric Hargett, Program Supervisor (Cheyenne)
Surface Water Quality Standards
307-777-7079