Proposed Regulations for Antidegradation

This webpage provides information on Nevada’s rulemaking process for establishing an antidegradation program to maintain and protect the quality of surface waters of the State.  All meetings, hearings, documents, and correspondence pertaining to the rulemaking process are accessible below.  To access archived regulation versions and associated workshop/hearing materials and associated public comment - Click Here

The Nevada Division of Environmental Protection (NDEP) is proposing a regulatory action for adoption of an updated antidegradation program with clear implementation procedures that would be applicable to all surface waters of the State. 

The objective of antidegradation is to protect water quality of the associated beneficial uses of Nevada’s surface waters and maintain the unique attributes and special characteristics and values associated with high-quality waters.  This objective is achieved through adoption of an antidegradation program and implementation procedures to ensure that waters are protected from regulated activities that have the potential to lower the water quality.  

Regulation Summary

The proposed regulation establishes four tiers of antidegredation protection with specific provisions for each category. Tier 1 protects water quality for beneficial uses of the water on a parameter-by-parameter basis. Tier 2 protects high-quality waters where data show the quality is better than levels needed to protect beneficial uses. Absent data, a waterbody is assumed to merit Tier 2 protection while data are collected to confirm whether this level of antidegredation protection is warranted. Processes are described to allow: (1) project permitting to proceed during the interim of assessing if water quality warrants Tier 2 protection; and (2) degradation of a Tier 2 water if the project/discharge is deemed by the Commission as socioeconomically important and necessary. Tier 2.5 and Tier 3 protect water quality and the special characteristics of waterbodies designated with the beneficial use of “extraordinary ecological, aesthetic, or recreational value” (NAC 445A.122). While new non-degrading discharges are allowable in Tier 2.5 waters, Tier 3 prohibits any new discharges.

The current antidegredation regulation proposal differs from the version that was set to go to the January 2023 State Environmental Commission in two manners. The current proposal does not include a process to nominate waterbodies to be designated for the beneficial use of “extraordinary aesthetical, ecological, or recreational value” and it includes a process to establish an interim baseline value. Because of this, the regulation has been significantly restructured. No other significant content changes were made.

Supporting Documents

Question or inquiries, please contact:
Bureau of Water Quality Planning
901 S. Stewart Street, Suite 4001
Carson City, NV 89701

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