Final Rule: New Waters of the US Definition Under the Clean Water Act

Posted on 1/3/2023 by Roger Marks

US EPA and the US Army have completed a Final Rule to revise the definition for “waters of the United States” or WOTUS, a phrase with major implications for Clean Water Act compliance. The latest attempt to define WOTUS restores the definition that was in place before a 2015 Final Rule, with revisions that reflect relevant Supreme Court decisions.

A pre-publication version of the Final Rule is available on EPA’s website. The Final Rule will take effect 60 days after it is published in the Federal Register.

Lion Members: Lion instructors and subject matter experts are reviewing the text of the Final Rule and will share details and insights about the new definition of WOTUS in a Member Bulletin next week.

How Does the Final Rule Define WOTUS?

The forthcoming Final Rule, which EPA states is consistent with the general framework of the 1986 regulations, defines WOTUS to include:

  • Traditional navigable waters, the territorial seas, and interstate waters (“paragraph (a)(1) waters”);
  • Impoundments of “waters of the United States” (“paragraph (a)(2) impoundments”);
  • Tributaries to traditional navigable waters, the territorial seas, interstate waters, or paragraph (a)(2) impoundments when the tributaries meet either the relatively permanent standard or the significant nexus standard (“jurisdictional tributaries”);
  • Wetlands adjacent to paragraph (a)(1) waters, wetlands adjacent to and with a continuous surface connection to relatively permanent paragraph (a)(2) impoundments, wetlands adjacent to tributaries that meet the relatively permanent standard, and wetlands adjacent to paragraph (a)(2) impoundments or jurisdictional tributaries when the wetlands meet the significant nexus standard (“jurisdictional adjacent wetlands”); and
  • Intrastate lakes and ponds, streams, or wetlands not identified in paragraphs (a)(1) through (4) that meet either the relatively permanent standard or the significant nexus standard (“paragraph (a)(5) waters”)

The Rule includes discussion of  key terms and criteria in the list above, including "adjacent wetlands" and "relatively permanent." 

From the Final Rule:  

“When upstream waters significantly affect the integrity of waters for which the Federal interest is indisputable—the traditional navigable waters, the territorial seas, and the interstate waters—this rule ensures that Clean Water Act programs apply to protect those paragraph (a)(1) waters by including such upstream waters within the scope of 'waters of the United States.'

Where waters do not significant affect the integrity of waters for which Federal interest is indisputable, this rule leaves regulation exclusively to the Tribes and States.”


Why WOTUS Matters 

The definition of Waters of the United States (WOTUS) tells the regulatory community which bodies of water are subject to EPA Clean Water Act programs, including, but not limited to: 

  • Spill Prevention, Control, and Countermeasure (SPCC) Planning.
  • Oil spill notifications.
  • NPDES permitting.
  • Stormwater discharge.
  • ​Dredge-and-fill

The Clean Water Act (CWA) prohibits unauthorized discharge of pollutants from a point source into the “waters of the United States.” Congress did not define “waters of the United States” (WOTUS) in the law. Instead, they left it to US EPA and the US Army Corps of Engineers to define the term in regulation.

First Complete EPA Regulations Training of 2023!

If you’re new to the EH&S field or need an update on changing EPA rules, Lion's live webinars are a convenient way to quickly build up critical expertise.

On February 2–3, join an environmental compliance expert for live Complete Environmental Regulations training to identify the EPA regulatory programs that impact your facility. This two-day webinar is updated to cover new and changing environmental regulations you should know about, including: 

  • Latest updates on EPA's new Waters of the US (WOTUS) Rule
  • Major Lautenberg Law amendments to TSCA
  • The latest Clean Air Act requirements for facilities
  • And much more!

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Final Rule: New Waters of the US Definition Under the Clean Water Act

Tags: Clean Water Act, environmental compliance, Waters of the United States, WOTUS

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