Lion will be closed on Monday, February 16, 2026. Online training support is available via support@lion.com.
Search

EPA Redefines “Waters of the United States”

Posted on 6/8/2015 by Roger Marks

On May 27, US EPA in cooperation with the US Army Corps of Engineers (USACE) announced a Final Rule to restructure the definition of “Waters of the United States.” The definition, which sets the standard for which bodies of water EPA is authorized to regulate under its Clean Water Act, has been a point of confusion and contention for environmental regulators and industry groups for decades.

The new rule will affect industry compliance with all Clean Water Act programs, most notably:
  • Oil Discharge Notifications (40 CFR 110);
  • Spill Prevention, Control, and Countermeasure Plans (40 CFR 112);
  • NPDES Permitting and Stormwater Discharge Permits (40 CFR 122);
  • The “per-industry standards” (40 CFR 405-471); and
  • Dredge and Fill Permitting (33 CFR 323).
How the Final Rule Affects CWA Compliance

The Final Rule will affect enforcement of the Clean Water Act in a number of major ways.

First, it puts certain bodies of water under the scope of EPA water regulations “by rule.” These jurisdictional waters are under EPA’s authority in all instances. They are:
  • Traditional navigable waters (per the 1899 Rivers and Harbors Act);
  • Interstate waters, including interstate wetlands;
  • Territorial Seas;
  • Impoundments of Jurisdictional Waters;
  • Tributaries to traditional navigable waters, interstate waters, and the territorial sea; and
  • Surface waters adjacent to the above waters, including adjacent wetlands.

What Does EPA Mean by “Tributary”?

The final rule gives a more precise definition of tributaries as “waters that are characterized by the presence of physical indicators of flow—bed and banks and ordinary high water mark—and contribute flow directly or indirectly to a traditional navigable water, interstate water, or territorial seas.”

EPA contends that these indicators illustrate that there is enough volume, frequency, and flow of water to constitute a “significant nexus” between the tributary and a jurisdictional water, therefore making the tributary subject to Clean Water Act rules.
 
EPA oil discharge in 2015 waters of the US

What Is a “Significant Nexus”?

The phrase “significant nexus” has itself been a point of confusion for industry and regulators. The term was coined and used in US Supreme Court decisions regarding major challenges to EPA’s water authority. The Supreme Court used this phrase to mean that, to regulate a body of water not already covered by the Clean Water Act, EPA must show that the body of water could “affect the chemical, physical, or biological integrity of a jurisdictional water.”

There are five types of waters EPA has determined will be subject to a case-by-case analysis to determine if they meet the “significant nexus” threshold:
  • Prairie potholes;
  • Carolina and Delmarva bays;
  • Pocosins;
  • Western vernal pools in California; and
  • Texas prairie wetlands.
Also included in the Final Rule are standards for evaluating other bodies of water on a case-by-case basis, namely those within the 100-year floodplain of a jurisdictional water and those within 4,000 feet of the high tide line or ordinary high water mark of jurisdictional water.

Old and New Exclusions

The new Final Rule retains all the exclusions from the definition of “Waters of the US” and adds a few more that reflect longstanding Agency practice. EPA added exclusions for certain ditches, groundwater and erosional features, stormwater control or treatment conveyances, and cooling ponds created in dry land.

The Final Rule goes into effect 60 days after its publication in the Federal Register, during which time it will likely face continued challenges.

Interactive Workshops for Environmental Professionals

Learn what you must report, collect, and keep on file to meet your legal responsibilities under the EPA’s major programs. From permitting and reporting under the Clean Water Act and Clean Air Act to chemical management and reporting under TSCA, FIFRA, EPCRA, and more, Lion Technology’s Complete Environmental Regulations Workshop will prepare you to confidently navigate the EPA regulations that affect your facility.

 

Tags: Act, Clean, EPA, new rules, Water, WOTUS

Find a Post

Compliance Archives

Lion - Quotes

The instructor created a great learning environment.

Avinash Thummadi

CAD & Environmental Manager

Lion's information is very thorough and accurate. Presenter was very good.

Melissa Little

Regulatory Manager

The instructor kept the class engaged and made learning fun. There was a lot of information to cover but time flew by. I will definitely use Lion in the future!

Chelsea Minguela

Hazmat Shipping Professional

Lion is my preferred trainer for hazmat and DOT.

Jim Jani

Environmental Coordinator

I was able to present my scenario to the instructor and worked thru the regulations together. In the past, I attended another training firm's classes. Now, I have no intention of leaving Lion!

Diana Joyner

Senior Environmental Engineer

The instructor was very very informative, helpful, understandable and pleasant. This course answered many questions I had, being new to this industry.

Frances Mona

Shipping Manager

Excellent class, super instructor, very easy to follow. No rushing through material. Would like to take his class again.

Lawrence Patterson

EH&S Facility Maintenance & Security Manager

The online course was well thought out and organized, with good interaction between the student and the course.

Larry Ybarra

Material Release Agent

Lion was very extensive. There was a lot of things that were covered that were actually pertaining to what I do and work with. Great Job. I will be coming back in three years!

Tony Petrik

Hazmat Shipping Professional

Convenient; I can train when I want, where I want.

Barry Cook

Hazmat Shipping Professional

Download Our Latest Whitepaper

In-flight hazmat incidents can be disastrous. This guide gives 5 tips for first-time air shippers to consider before offering dangerous goods for transportation on passenger or cargo aircraft.

Latest Whitepaper

By submitting your phone number, you agree to receive recurring marketing and training text messages. Consent to receive text messages is not required for any purchases. Text STOP at any time to cancel. Message and data rates may apply. View our Terms & Conditions and Privacy Policy.