NEWS RELEASE
Contact: Society for Freshwater Science
Attn: Natalie Myers, Media Officer
communications@freshwater-science.org | 360-990-3631
freshwater-science.org
Changes to the Waters of the U.S. (WOTUS) Definition
The consequences and response from SFS President Sally Entrekin
December 30, 2025 — The Society for Freshwater Science (SFS) today released a letter outlining proposed changes to the Waters of the U.S. (WOTUS) definition and our response.
Dear SFS Members,
As many of you are aware, the Waters of the U.S. (WOTUS) are continuing to be more strictly defined, thereby limiting federal protection. The comment period opened on November 17, 2025, and closes January 5, 2026. You can find relevant information on this U.S. EPA webpage.
Susan Colvin (Science and Policy Committee member), working with Nayeli Sanchez, Robert Keast, and Patrick Shirey, has provided the following synthesis information. They are submitting formal comments and have shared the main points with me to share with our SFS membership. I provided some additional information from the federal register and websites, cited below, for your information. American Fisheries Society (AFS) and others at the Consortium of Aquatic Scientists, including SFS, will be signing on to a joint comment letter. If you find any errors, have concerns, or questions, please direct them to Sally Entrekin (president@freshwater-science.org).
The rule with the updated definition can be found here as a downloadable pdf. You can submit a comment on the definition here.
Changes to the definition, as summarized in the Federal Register (cut and pasted from the above reference):
B. Summary of the Major Provisions of the Regulatory Action. The agencies are proposing to revise the following categories of ‘‘waters of the United States’’ under 33 CFR 328.3 and 40 CFR 120.2 paragraph (a) by deleting the interstate waters category under paragraph (a)(1)(iii) and deleting ‘‘intrastate’’ from the paragraph (a)(5) category for lakes and ponds. In addition, ministerial changes are proposed to add in one place and delete in another place an ‘‘or’’ from paragraph (a)(1) to conform to the deletion of the interstate waters category. In addition, the agencies are proposing to revise the following exclusions: the (b)(1) waste treatment system exclusion, the (b)(2) prior converted cropland exclusion, and the (b)(3) ditch exclusion. The agencies are also proposing to add an exclusion for groundwater at (b)(9). The agencies are also proposing to add definitions of ‘‘continuous surface connection,’’ ‘‘ditch,’’ ‘‘prior converted cropland,’’ ‘‘relatively permanent,’’ ‘‘tributary,’’ and “waste treatment system’’ in paragraph (c) of their regulations.
C. Costs and Benefits. Potential costs and benefits would be incurred as a result of actions taken under existing Clean Water Act programs (i.e., sections 303, 311, 401, 402, and 404) that implement and follow this proposed rulemaking. Entities currently are, and would continue to be, regulated under these programs that rely on the definition of ‘‘waters of the United States’’ under the Clean Water Act. The agencies prepared the Regulatory Impact Analysis for the Proposed Rule Updated Definition of Waters of the United States (‘‘Regulatory Impact Analysis for the Proposed Rule’’), available in the rulemaking docket, for informational purposes to analyze the potential cost savings and forgone benefits associated with this proposed action. The agencies analyzed the potential cost savings and forgone benefits against the baseline of the Amended 2023 Rule. The analysis is summarized in section VI of this preamble.
How will the new definition change WOTUS?
“EPA’s review will be guided by the Supreme Court’s decision in Sackett v. Environmental Protection Agency, which stated that the Clean Water Act’s use of ‘waters’ encompasses only those relatively permanent, standing or continuously flowing bodies of water forming streams, oceans, rivers and lakes. The Sackett decision also clarified that wetlands would only be covered when having a continuous surface connection to waterbodies that are ‘waters of the United States” in their own right.” - EPA, March 12, 2025
The proposed 2025 Waters of the United States (WOTUS) definition narrows the scope of protection under the Clean Water Act (CWA) compared to prior rules, substantially weakening federal protection of U.S. waters. With the passage of the CWA in 1972, Congress aimed “to restore and maintain the chemical, physical, and biological integrity of the nation's waters.” To achieve this, the CWA curbed pollutant discharges and restricted the dredging and filling of waters, including wetlands, to protect water quality for fish, wildlife, recreation, and human consumption. Congress intended to make the waters fishable and swimmable. The proposed rule will not meet the intentions of the CWA and it is neither clear nor durable for determining jurisdiction.
What are the primary changes to the protection of:
Streams and rivers
- Perennial: Should not change current protections.
- Non-perennial. If the final rule protects only perennial waters, federal jurisdiction could lose up to 8 million miles of streams (NRDC 2025). This legal definition conflicts with water connectivity science (EPA 2015). Headwaters process and retain significant nutrients (e.g., nitrogen), protecting the chemical integrity of downstream navigable waters (Alexander et al. 2007). Headwater streams (first through third order) comprise roughly 53% of US streams and 79% of total stream length (Colvin et al. 2019, Nadeau and Rains 2007). Crucially, 60% of US streams flow only seasonally or after precipitation, and these provide over half the volume of downstream waters (US EPA 2019; Brinkerhoff et al. 2024). The proposed rule, therefore, leaves half the nation’s flow without federal protection.
Wetlands
- Under the new rule, wetlands must have water throughout a yet-to-be-defined “wet season” and maintain a continuous surface connection with navigable water. Wetlands that dry during the wet season, or those separated by structures like levees, berms, or roads, will not be protected. Wetlands in a mosaic will be subject to individual agency delineation, again reducing important off-channel water storage and ecosystem services such as processing pollutants. The most restrictive interpretation of the change projects up to 84% of wetlands that previously required a federal permit to dredge or fill would no longer be covered under the CWA (NRDC 2025). Their loss will lead to increased risk of flooding and degraded water quality (Acreman and Holden 2013; Creed et al. 2017).
Overall Consequences
This rulemaking ultimately leaves critical systems supporting drinking water, floodwater storage, and biodiversity unprotected, systems vital for our nation’s security and economic prosperity. Public polls show that 72% of the U.S. public supports restoring federal protections of wetlands and streams to pre-rollback levels, and 96% of voters believe protecting the water in lakes, streams, and rivers is important (Walton Family Foundation 2024). Yet, the proposed WOTUS rule further weakens these protections. For the 24 states relying solely on the CWA, this creates a total regulatory vacuum, leaving those waters with little to no state or federal oversight (Sullivan et al 2025).
Press Releases on Websites
https://narf.org/headwaters-wotus-2025/
https://www.epa.gov/newsreleases/administrator-zeldin-announces-epa-will-revise-waters-united-states-rule on March 12, 2025
https://www.epa.gov/system/files/documents/2025-11/updated_definition_wotus_nprm.pdf
Peer-Reviewed References
Acreman, M. & Holden, J. (2013). How wetlands affect floods. Wetlands 33, 773–786.
Alexander, R. B., Boyer, E. W., Smith, R. A., Schwarz, G. E., & Moore, R.B. (2007). The role of headwater streams in downstream water quality. Journal of the American Water Resources Association, 43, 41-59.
Brinkerhoff, C. B., Gleason, C. J., Kotchen, M. J., Kysar, D. A., & Raymond, P. A. (2024). Ephemeral stream water contributions to United States drainage networks. Science, 384, 1476–1482. https://doi.org/10.1126/science.adg9430
Creed, I. F. et al. (2017). Enhancing protection for vulnerable waters. Nat. Geosci. 10, 809–815.
Colvin, S. A. R., Sullivan, S. M. P., Shirey, P. D., Colvin, R. W., Winemiller, K. O., Hughes, R. M., Fausch, K. D., Infante, D. M., Olden, J. D., Bestgen, K. R., Danehy, R. J., & Eby, L. (2019). Headwater streams and wetlands are critical for sustaining fish, fisheries, and ecosystem services. Fisheries, 44: 73-91. https://doi.org/10.1002/fsh.10229
Nadeau, T. L., & Rains, M. C. (2007). Hydrological connectivity between headwater streams and downstream waters: how science can inform policy. Journal of the American Water Resources Association, 43 118–133.
Natural Resources Defense Council (2025). Mapping Destruction: Using GIS modeling to show the disastrous impacts of Sackett v. EPA on America’s Wetlands. https://www.nrdc.org/resources/mapping-destruction
Sulliván, S. M. P., Hughes, R. M., Vadas, R. L., Davies, G. T., Shirey, P. D., Colvin, S. A. R., Infante, D. M., Danehy, R. J., Sanchez, N. K., & Keast, R. B. (2025). Waterbody connectivity: linking science and policy for improved waterbody protection. BioScience, 75, 68–91. https://doi.org/10.1093/biosci/biae117
U.S. EPA. (2015). Connectivity of Streams and Wetlands To Downstream Waters: A Review and Synthesis of the Scientific Evidence. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-14/475F.