Wading Into Wetlands: How Sackett v. EPA Unleashed the Threat of Increasing Flood Risk Through Wetland Development
Andrew Capps
The Supreme Court’s decision in Sackett v. Environmental Protection Agency[1] is the most recent development in the Court’s forty years of judicial wrangling of the meaning of “waters of the United States” in the Clean Water Act (CWA).[2] The ruling removed wetlands that do not have a surface connection to navigable bodies of water from federal jurisdiction under the CWA. Thus, Sackett excludes these wetlands from the Environmental Protection Agency’s (EPA) protections against pollutants and the U.S. Army Corps of Engineers’ (Corps) regulations on dumping fill material. As a result, in nearly half of states, noncontiguous wetlands are no longer protected from pollution, development, or destruction. The removal of these protections increases the risk of flooding in communities around the country by encouraging development within these wetlands and enabling their destruction.
For decades, development was a key driver of wetlands destruction in the United States, accounting for the destruction of an estimated half of the country’s wetlands areas in just the past century.[3] It wasn’t until 1972 that Congress took action to control pollution of the country’s rivers and destruction of its wetlands with the CWA. Broadly put, the CWA empowers the EPA to regulate the discharge of pollutants into “waters of the United States” under § 402,[4] and it allows the Corps to regulate the discharge of dredged or fill material into such waters under § 404.[5] Notably, the CWA was amended in 1977 to support the Corps’ claim that its jurisdiction extended to “adjacent wetlands.”[6]
The full history of the Court’s interpretation of “waters of the United States” as it relates to noncontiguous wetlands under the CWA is outside the scope of this blog, but understanding the landscape prior to Sackett illustrates the decision’s impact. Put briefly, prior to Sackett, federal agencies determined CWA jurisdiction over noncontiguous wetlands based on Justice Anthony Kennedy’s concurring opinion in Rapanos v. United States, which required a “significant nexus” between wetlands and a navigable body of water for CWA jurisdiction.[7] With Justice Samuel Alito’s majority opinion in Sackett, the Court rejected the “significant nexus” test and adopted Justice Antonin Scalia’s plurality opinion from Rapanos, which espoused a clear and exclusive requirement that wetlands have a “continuous surface connection” to a navigable body of water to be subject to federal jurisdiction under the CWA.[8]
As a replacement for the loss of federal jurisdiction under the CWA, the Court noted, “[s]tates can and will continue to exercise their primary authority to combat water pollution by regulating land and water use.”[9] However, 24 states rely on the CWA’s authority and jurisdiction to protect their own wetlands areas, meaning that Sackett left nearly half of states without any permitting regime to protect such wetlands from destruction.[10] This leads to the most critical consequence of Sackett’s exclusion of noncontiguous wetlands from CWA jurisdiction: roughly half of wetlands areas previously protected under the “significant nexus” test were removed from federal oversight under the CWA.[11] That leaves state and local governments to shoulder the burden[12] of protecting these vital environmental resources from destruction and of protecting their communities from growing flood risk.[13]
Section 404 of the CWA creates a barrier to wetlands destruction by prohibiting the discharge of dredged of fill material into wetlands without a Corps permit.[14] The Corps’ permitting process is the primary enforcement mechanism for this prohibition, and it requires the Corps to conduct a jurisdictional determination to verify the existence of wetlands areas before issuing a permit for activities that would disturb wetlands. [15] By taking noncontiguous wetlands out of the Corps’ jurisdiction under the CWA, the Sackett decision removed this critical barrier to the destruction of these wetlands. This change threatens to substantially increase the risk of flooding in communities around the country because wetlands play a vital role “in reducing the frequency and intensity of floods by acting as natural buffers, soaking up and storing a significant amount of floodwater.”[16] As a result of enabling the destruction of noncontiguous wetlands, the Court in Sackett opened the door to growing flood risk.
Perhaps more importantly, the Sackett decision encourages development within noncontiguous wetlands by eliminating the obligation for developers to verify the absence of these wetlands before undertaking disruptive activities. Because of their seasonality and lack of surface connection to navigable bodies of water, the presence of wetlands—particularly noncontiguous wetlands that lack a surface water connection—is not always obvious.[17] The Court in Sackett noted that determining the presence of noncontiguous wetlands is difficult because “even if a property appears dry” it may still contain wetlands that were previously protected by the “significant nexus” test.[18] Prior to Sackett, that difficulty left developers facing an impasse between rolling the dice on an expensive expert consultant, taking their chances with a jurisdictional determination from Corps, or simply not building at all.[19] But with Sackett’s removal of noncontiguous wetlands from the Corps’ jurisdiction, developers can proceed without fear as long as any wetlands they might disturb lack a continuous surface connection to a navigable body of water.
Critically, without the need for a jurisdictional determination from the Corps, developers can build in areas containing noncontiguous wetlands without determining the extent of flood risk that decision entails for their developments. Noncontiguous wetlands are common in isolated depressions and low-lying areas saturated by rain or groundwater.[20] As a result, building within them comes with increased risk of flooding.[21] But without the jurisdictional determination requirement, that flood risk can be hidden. Instead, the next line of defense against building in flood-prone areas is often the Federal Emergency Management Agency’s (FEMA) Flood Insurance Rating Maps (FIRMs).[22] FEMA’s FIRMs visualize the projected extent of flooding by delineating flood zones where water is expected to cover the ground during intense storms.[23] These flood maps are heavily relied on to gauge flood risk at individual and community scales and to inform local development policies and decisions.[24] However, these maps do not reflect pluvial flooding, which is localized flooding caused by brief, excessive rainfall and runoff.[25] That’s a critical issue because, by Sackett’s definition, noncontiguous wetlands are disconnected from navigable bodies of water, like rivers, meaning flood risk in these wetlands is largely pluvial and not reflected on FEMA’s flood maps. As a consequence, development is encouraged to expand into these wetlands, increasing communities’ direct exposure to flood risk by locating buildings in areas that are more prone to flooding.[26] Ultimately, the result is that Sackett has unleashed the threat of increasing flood risk not only by enabling the destruction of these noncontiguous wetlands but also by encouraging development within these wetland areas where flood risk is often hidden.
[1] Sackett v. Env’t Prot. Agency, 598 U.S. 651 (2023).
[2] 33 U.S.C. § 1250 et seq.
[3] Blake Hudson and Mike Hardig, Isolated Wetland Commons and the Constitution, 2014 BYU L. Rev. 1443, 1450 (2015) (citing David Mareno-Mateos, Mary E. Power, Francisco A. Comıin & Roxana Yockteng, Structural and Functional Loss in Restored Wetland Ecosystems, 10 PLOS Biology 1, 1 (2012)).
[4] See 33 U.S.C. § 1342.
[5] See 33 U.S.C. § 1344.
[6] See United States v. Riverside Bayview Homes, Inc., 474 U.S. 121, 137-39 (1985).
[7] Rapanos v. United States, 547 U.S. 715, 782 (2006).
[8] Sackett, 598 U.S. at 678–79.
[9] Id. at 683.
[10] James McElfish, State Protection of Nonfederal Waters: Turbidity Continues, 52 Env’t L. Rep. 10679, 10684 (2022).
[11] See Ariel Wittenberg, Kevin Bogardus, EPA falsely claims ‘no data’ on waters in WOTUS rule, E&E News (Dec. 11, 2018) https://www.eenews.net/articles/epa-falsely-claims-no-data-on-waters-in-wotus-rule/ (noting the EPA determined 51 percent of wetlands protected by Justice Kennedy’s “significant nexus” test would be removed from federal jurisdiction under a proposed rule during President Donald Trump’s first term that aimed to remove the “significant nexus” test from federal agency’s interpretation of the CWA’s “waters of the United States” definition).
[12] See Casey E. Lindstrom, Comment, The Cost of Clarity: Closing the Floodgates on WOTUS Ambiguity and the Bleak Future of Wetlands Protections, 74 Case W. Rsrv. L. Rev. 865, 889 (2024).
[13] See Hudson and Hardig, supra note 3, at 1450.
[14] See 33 U.S.C. § 1344.
[15] Simpson Z. Fant Jr., Note, Sackett v. EPA: The Narrowing of “Waters of The United States” Under the Clean Water Act and its Downstream Effects on South Carolina Wetland Regulation, 75 S.C. L. Rev. 563, 566 (2024).
[16] See Hudson and Hardig, supra note 3, at 1450.
[17] U.S. Environmental Protection Agency, How Wetlands Are Defined and Identified Under CWA Section 404, (July 1, 2024) https://www.epa.gov/cwa-404/how-wetlands-are-defined-and-identified-under-cwa-section-404.
[18] Sackett, 598 U.S. at 669.
[19] Id. at 669-70.
[20] U.S. Environmental Protection Agency, What is a Wetland?, (April 24, 2025) https://www.epa.gov/wetlands/what
-wetland.
[21] Michael Lipske, Caution: Building in a Wetland Can Be Hazardous to Your House, Nat’l Wildlife Fed’n (June 1, 1998) https://www.nwf.org/Magazines/National-Wildlife/1998/Caution-Building-in-a-Wetland-Can-Be -Hazardous-to-Your-House.
[22] American Planning Association, Planning for Flood Resiliency: A Guide for Local Communities, PAS Report No. 584, at 14 (2018). (Available at https://planning-org-uploaded-media.s3.amazonaws.com/publication/online/PAS-Report-584.pdf).
[23] See e.g. FEMA’s National Flood Hazard Layer (NFHL) Viewer https://hazards-fema.maps.arcgis.com/apps/
webappviewer/index.html?id=8b0adb51996444d4879338b5529aa9cd.
[24] See Joel Scata, FEMA’s Outdated and Backward-Looking Flood Maps, National Resources Defense Council Expert Blog (Oct. 12, 2017), https://www.nrdc.org/bio/joel-scata/femas-outdated-and-backward-looking-flood-maps.
[25] U.S. Gov’t Accountability Off., GAO-22-104079, FEMA Flood Maps: Better Planning and Analysis Needed to Address Current and Future Flood Hazards, at 15 (2022).
[26] See Lipske, supra note 21.