A New Definition for Waters of the United States

On December 11, 2018, the U.S. Environmental Protection Agency (EPA) and Department of the Army (Army) proposed a revised definition for “waters of the United States.” The government first issued the final rule in 2015, but that was soon updated, in November 2015. Why is this new definition so significant? It affects which waters fall under Section 404 of the Clean Water Act (CWA) and must comply with the regulations of the EPA and the Army. According to the EPA Press Office, the proposed definition is “clear, understandable, and implementable” and clarifies federal authority under the CWA.

sunset over swamp in summer

A New Definition for Waters of the United States

EPA Acting Administrator Andrew Wheeler stated, “Our proposal would replace the Obama EPA’s 2015 definition with one that respects the limits of the Clean Water Act and provides states and landowners the certainty they need to manage their natural resources and grow local economies. For the first time, we are clearly defining the difference between federally protected waterways and state protected waterways. Our simpler and clearer definition would help landowners understand whether a project on their property will require a federal permit or not, without spending thousands of dollars on engineering and legal professionals” (source).

The Proposal

The proposal defines “waters of the United States” as including all of the following:

  • Traditional navigable waters (TNW)
  • Tributaries to traditional navigable waters
  • Certain ditches
  • Certain lakes and ponds
  • Impoundments of jurisdictional waters
  • Wetlands adjacent to jurisdictional waters

The proposal also specifies waters that are not “waters of the United States,” including the following:

  • Features that only contain water during or in response to rainfall
  • Groundwater
  • Many ditches, including most roadside and farm ditches
  • Prior converted cropland
  • Stormwater control features
  • Waste treatment systems

To further clarify which waters fall under the CWA and which do not, the EPA and the Army are exploring how they might work with federal, state, and tribal partners to develop a data or mapping system. They aim to make this information clear and publicly accessible to promote environmental protection.

Goals of the New Definition

With this new proposal, the EPA and the Army aimed to provide clarity for those affected, making it easier to understand which waters are “waters of the United States” and where the CWA applies. In addition to protecting America’s navigable waters, they believe this adjustment to the definition will provide cost savings, support economic growth, and promote business development by reducing obstacles (source).

The History of the Current Definition

  • August 2015: The Obama Administration enacts the current definition of “waters of the United States.” It includes all channels, wetlands, and ponds within 100 feet of a tributary to a TNW or within 1,500 feet of a TNW. This definition is broad and unclear, creating confusion. Several states take legal action against the 2015 Rule; varying rulings are issued.
  • October 2015: The U.S. Court of Appeals for the Sixth Circuit issues a nationwide stay of the 2015 Rule. As other court cases proceed, the rule is effective in some states and ineffective in others. In several courts and states, rulings are issued and overturned.
  • September 2018: At this point, the 2015 Rule only applies in 22 states. Earlier definitions of “waters of the United States” apply in the other 28 states. It’s very difficult to determine which waters are regulated and which are not. This inconsistency makes it difficult for businesses and landowners to comply with regulations and complete acquisition due diligence. Some demand a formal definition of “waters of the United States,” which would offer predictability and help industries comply with the law.

Proposal Feedback

Before the agencies developed this new definition, they invited those affected by the regulations to provide proposal recommendations, and they received more than 6,000 recommendations. If you would like to comment on the current proposal, you may do so for 60 days after the publication of the proposal in the Federal Register. The agencies will also host a listening session to further discuss the proposal with stakeholders. This was scheduled for January 23, 2019, in Kansas City, Kansas, but it was postponed due to the federal government shutdown. For updates on the status of the public hearing, head to the EPA website.

Once the public comment period has ended, the proposal may be finalized.


If you need help understanding or complying with the Clean Water Act, Environmental Works can help. We can also provide wetland delineations and assistance implementing BMPs, obtaining the required permits, and coordinating mitigation. To learn more, please contact us online. We would be happy to help!