New Mexico’s Water Quality Standards, codified at 20.6.4 NMAC, define water quality goals by designating uses for rivers, streams, lakes and other surface waters, setting criteria to protect those uses, and establishing antidegradation provisions to preserve water quality. The standards are adopted through a rulemaking process by the Water Quality Control Commission ("WQCC"), then approved by the United States Environmental Protection Agency (U.S. EPA) for purposes under the federal Clean Water Act. The process for developing and amending water quality standards is outlined in the State's approved Water Quality Management Plan and Continuing Planning Process.
Water quality standards can be amended at any time. However, in accordance with Section 303(c)(1) of the CWA and 220.127.116.11 New Mexico Administrative Code, states are required to hold a public hearing at least once every three years to review, amend, and adopt water quality standards, as applicable. This is referred to as a “Triennial Review.” Because of the administrative process to amend regulations and make them effective for both state and Clean Water Act purposes, the Department petitions for a Triennial Review hearing date three years from the date EPA makes the last Triennial Review amendments effective for Clean Water Act purposes. For a list of past Triennial Reviews and other Water Quality Standard amendments please click here.
There are several types of water quality standards amendments. They are as follows:
- Removing or Replacing a Designated Use.
- To amend a Designated Use to one with less stringent criteria, a Use Attainability Analysis must be conducted as part of the supporting evidence to amend.
- Amending a Designated Use to one with more stringent criteria does not require a UAA but does require supporting evidence for the WQCC to consider a petition for a hearing to amend.
- Site-Specific Criteria.
- Temporary Standards.
- Amending Criteria (Narrative or Numeric). These are generally reviewed and amended during a Triennial Review.
- Designated Outstanding National Resource Waters (“ONRWs”).
- New Mexico’s Water Quality Standards as approved by the New Mexico’s Water Quality Control Commission effective, for purposes of state implementation, as of September 24, 2022 and approved
- New Mexico Water Quality Standards as approved by EPA effective, for Clean Water Act Purposes, July 24, 2020.
- EPA-Approved Tribal Standards