Audit, Compliance and Risk Blog

Another Round of EPA and Corps of Engineers Proposals to Redefine “Waters of the United States”

Posted by Jon Elliott on Tue, Feb 26, 2019

Mississippi RiverOn December 11, 2018 the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) jointly proposed to revise their regulatory definitions of “waters of the United States”, applying authority under the Clean Water Act (CWA). CWA does not define this term clearly, so after decades of rulemakings and litigation, it remains in dispute. Generally, Democratic presidents and the judges they appoint tend to support geographically and semantically broad applications, while with Republican presidents and the judges they appoint tend to take narrower views. The latest proposal would narrow the definition, reversing Obama-era rules adopted in June 2015, and presently in effect in 22 states based on the present status of ongoing judicial appeals (I summarized the 2015 rules, and the litigation leading up to them here and the Trump-era EPA’s 2017 proposal to roll back the 2015 revisions here). The agencies characterize this narrowing as an increase in certainty for stakeholders, accomplished by eliminating some of the site-specific discretion that the 2015 rules provided to permit writers. Because of the government shutdown, this latest proposal was not published in the Federal Register until February 14, 2019.

What is the Proposed Definition?

EPA and the Corps are proposing to adopt consistent definitions, based on categories of waters. First, they define six categories of waters they will consider to be waters of the United States:

  • Traditional navigable waters that are used in interstate or foreign commerce, consisting of large rivers and lakes, tidal waters, and territorial seas, as well as tidally influenced waterbodies, including wetlands, along coastlines.

  • Tributaries, consisting of rivers and streams which may not be navigable themselves but which flow to traditional navigable waters. To qualify, they must be perennial or at least intermittent, not just ephemeral features (such as western arroyos) that flow only immediately after rain. They can connect to traditional navigable waters directly, or through other intervening non-jurisdictional surface waters that are perennial or intermittent.

  • Certain ditches – which the proposal defines as an “artificial channel used to convey water.” Ditches qualify if they are traditionally navigable (such as the Erie Canal), subject to the ebb and flow of the tide, or qualify as tributaries and were constructed in a tributary or built in adjacent wetlands.

  • Certain lakes and ponds – which are traditional navigable waters (such as the Great Salt Lake), or which contribute perennial or intermittent flow to a traditional navigable water either directly, or through other surface waters that convey perennial or intermittent flow, or which are flooded by a “water of the United States” in a typical year.

  • Impoundments of “waters of the United States”.

  • “Adjacent wetlands,” which physically touch other jurisdictional waters or have a surface water connection in a typical year due to inundation from a “water of the United States” or have perennial or intermittent flow between the wetland and a “water of the United States.” Wetlands near a jurisdictional water that don’t physically touch because of a barrier (such as a berm, levee, or upland) are adjacent only where they have a surface water connection through or over the barrier, including wetlands flooded by jurisdictional waters in a typical year.

The proposal excludes waters in the categories listed above that don’t meet the applicable qualifying criteria, which includes the Obama-era rules’ incorporation of the “significant nexus” benchmark derived from Supreme Court precedent. They also exclude, and wastewater conveyances. They also exclude groundwater, “prior converted cropland” (defined based on Department of Agriculture rules as “any area that, prior to December 23, 1985, was drained or otherwise manipulated for the purpose, or having the effect, of making production of an agricultural product possible”), and wastewater conveyances.

The proposal notes that these definitions, and the federal policies they drive, will not preempt states’ authority to regulate waters that are not “waters of the United States.” Some states, such as California, already do so.

Now What?

The proposal's publication in the February 14 Federal Register started a 60 day comment period, so comments are due by April 15. After that the agencies anticipate moving to issue final rules. Once the proposal is finalized, it’s easy to anticipate another round of litigation.

Self-assessment Checklist

Does my organization routinely discharge wastewaters:

  • Into a natural water body?

  • Into an artificial conveyance (ditch, storm sewer, etc.)?

  • Into a sanitary sewer system

Does my organization operate a facility where rainwater or snowmelt might flow:

  • Into a natural water body?

  • Into an artificial conveyance (ditch, storm sewer, etc.)?

Is my organization undertaking a construction or other project that disturbs a waterway, or disturbs soil or rock that might contaminate runoff into a waterway?

Has my organization evaluated the receiving waters to determine whether they qualify as “waters of the United States” subject to CWA requirements?

    • Under the proposed definition from December 2018?
    • Under definitions included in the May 2015 regulation?

Has my organization evaluated requirements under state laws in each state in which activities may affect water bodies or wetlands?

Where Can I Go For More Information?

Specialty Technical Publishers (STP) provides a variety of single-law and multi-law services, intended to facilitate clients’ understanding of and compliance with requirements. 

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About the Author

Jon Elliott is President of Touchstone Environmental and has been a major contributor to STP’s product range for over 25 years. 

Mr. Elliott has a diverse educational background. In addition to his Juris Doctor (University of California, Boalt Hall School of Law, 1981), he holds a Master of Public Policy (Goldman School of Public Policy [GSPP], UC Berkeley, 1980), and a Bachelor of Science in Mechanical Engineering (Princeton University, 1977).

Mr. Elliott is active in professional and community organizations. In addition, he is a past chairman of the Board of Directors of the GSPP Alumni Association, and past member of the Executive Committee of the State Bar of California's Environmental Law Section (including past chair of its Legislative Committee).

You may contact Mr. Elliott directly at:


photo credit: Jason Fiori East of the Mississippi via photopin (license)

Tags: Environmental risks, Environmental, EPA, effluent, clean water