New Mexico waters insulated from federal changes to Clean Water Act coverage

As the federal government looks to narrow the definition of waters of the United States, New Mexico’s wetlands and ephemeral waters will still have regulatory protections thanks to a 2025 state permitting law.

“Even as the federal government continues to roll back and narrow that definition, rolling back 50 years plus of Clean Water Act protections that communities have thrived on across the nation and especially here in New Mexico, those waters will now be protected by the state,” said Tricia Snyder, Rivers and Waters Program director for advocacy group New Mexico Wild.

The 2023 U.S. Supreme Court decision in Sackett v. EPA changed which waters in the United States are regulated by the Clean Water Act, meaning less regulation for some industries and more potential for pollution for some waters.

In 2025, New Mexico’s state Legislature passed the Pollutant Discharge Elimination System Act, creating new permitting requirements meant to protect ephemeral and intermittent waters no longer covered under the Clean Water Act.

Ephemeral waters don’t run year-round. Instead, they run after a rainstorm or other precipitation or when groundwater levels get high enough.

“While they're not the iconic rivers like the Rio Grande and the Pecos and the Gila, they feed those rivers,” Snyder said. “They dump water into those iconic waterways, and so if those ephemeral and intermittent waterways are polluted, then we're going to have a bigger problem with some of our bigger waterways.”

Until end of day Monday, the U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers are accepting public comment on proposed changes to the definition of waters of the United States meant to bring federal agencies’ policy in line with the Supreme Court decision.

“When it comes to the definition of ‘waters of the United States,’ EPA has an important responsibility to protect water resources while setting clear and practical rules of the road that accelerate economic growth and opportunity,” EPA Administrator Lee Zeldin said in a statement. “Democrat Administrations have weaponized the definition of navigable waters to seize more power from American farmers, landowners, entrepreneurs and families.”

The proposed changes include limiting wetlands covered by the Clean Water Act to wetlands that touch jurisdictional waters and have continuous surface connections during a wet season. The new definition would include traditionally navigable waters like rivers, lakes and oceans, and tributaries, lakes and ponds that are standing or continuously flowing surface waters year-round or at least during a wet season. Waters that cross state lines would not automatically be included in the definition. The proposed rule clarifies definitions of excluded items like ditches, converted cropland and waste treatment systems and creates an explicit exclusion for groundwater. It also creates new definitions for terms like "tributary," "continuous surface connection" and "relatively permanent."

The changes could affect when companies or people need permits for discharging pollutants, or dredge and fill permits for construction and activities that disturb wetlands. The proposed rule could also affect oil spill prevention and response requirements.

The Biden administration already made changes to the rule in 2023 after the Supreme Court decision, changes environmental advocates say did enough to match federal policy with the Supreme Court decision.

During a virtual public comment session on the proposed rule change, Kelly Hunter Foster, a senior attorney at the nonprofit Waterkeeper Alliance, said the Trump administration’s proposed definition goes far beyond the Supreme Court decision “and would dramatically eliminate federal protections against uncontrolled pollutant discharges for many, if not most, rivers, streams, wetlands and other waters across the country.”

“We urge the agencies to abandon this ill-conceived proposal that doesn't clarify anything but would obstruct achievement of the Clean Water Act's fundamental objective of restoring and maintaining the chemical, physical and biological integrity of the nation's waters,” she said.

But some industry groups affected by the water regulations are in favor of the Trump administration’s proposed changes and want even narrower definitions.

Louis Baer, associate general counsel for the National Mining Association, said the proposed rule would give mining operators a clear and consistent definition of waters of the United States and right-size the scope of the definition. Although, the association recommends simplifying the definition of tributary.

“The mining industry also appreciates the clear exclusions for ditches, wastewater treatment systems and groundwater,” Baer said.

The Associated General Contractors of America also supports the proposed rule, said Melinda Tomanio, who works on sustainability issues for the organization.

“The scope of federal control over waters affects local land use decisions and determines whether our members can move forward in a timely and cost effective manner with projects that improve communities,” Tomanio said.

Whatever definition is greenlit at the federal level, New Mexico’s new permitting program still needs funding as it gets set up, and state officials still need to do rulemaking to determine day-to-day specifics of the program not included in statute.  

The new state law "raises important questions around definitions, jurisdiction, and permitting complexity and costs that are best addressed through a careful and transparent rule-making process," Matt Thompson, executive director of the New Mexico Mining Association, said in a statement. 

"The New Mexico Mining Association looks forward to working collaboratively with the New Mexico Environment Department to ensure the final rules enact water quality protections while avoiding unnecessary duplication, unpredictable costs, and unreasonable delays," Thompson said.

Once fully implemented, the state program could cost $8 million annually, Snyder said. Some states fund similar programs through fees, while others use state coffers. Most states have a hybrid approach, using fees and state dollars to pay for permitting, Snyder said.

“The bottom line is that the vast majority of New Mexico's waters now no longer have federal protection. … So, it's paramount that we get our state program up and running as quickly as possible,” Snyder said.

Cathy Cook covers the federal government for the Albuquerque Journal. Reach her via email at ccook@abqjournal.com.