{"abstract":"The purpose of this supplemental notice of proposed rulemaking is for the U.S. Environmental Protection Agency (EPA) and the Department of the Army (\"the agencies\") to supplement and seek additional comment on certain aspects of an earlier proposal, published on November 20, 2025, to revise the regulations defining the scope of waters federally covered under the Clean Water Act in light of the U.S. Supreme Court's 2023 decision in Sackett v. Environmental Protection Agency. As stated in the agencies' November 20, 2025 Notice of Proposed Rulemaking (NPRM), the agencies intend for this rulemaking to provide greater regulatory certainty and increase Clean Water Act program predictability and consistency by clarifying the definition of \"waters of the United States.\" After consideration of the public comments received on the NPRM, the agencies are issuing this notice to supplement the NPRM with additional regulatory options on certain aspects of the proposed rule.","action":"Supplemental notice of proposed rulemaking.","agencies":[{"raw_name":"DEPARTMENT OF DEFENSE","name":"Defense Department","id":103,"url":"https://www.federalregister.gov/agencies/defense-department","json_url":"https://www.federalregister.gov/api/v1/agencies/103","parent_id":null,"slug":"defense-department"},{"raw_name":"Department of the Army, Corps of Engineers","name":"Engineers Corps","id":142,"url":"https://www.federalregister.gov/agencies/engineers-corps","json_url":"https://www.federalregister.gov/api/v1/agencies/142","parent_id":103,"slug":"engineers-corps"},{"raw_name":"ENVIRONMENTAL PROTECTION AGENCY","name":"Environmental Protection Agency","id":145,"url":"https://www.federalregister.gov/agencies/environmental-protection-agency","json_url":"https://www.federalregister.gov/api/v1/agencies/145","parent_id":null,"slug":"environmental-protection-agency"}],"body_html_url":"https://www.federalregister.gov/documents/full_text/html/2026/09/09/2026-18317.html","cfr_references":[{"chapter":null,"citation_url":null,"part":"328","title":33},{"chapter":null,"citation_url":null,"part":"120","title":40}],"citation":"91 FR 57284","comment_url":"http://www.regulations.gov/commenton/EPA-HQ-OW-2025-0322-15447","comments_close_on":"2026-10-09","correction_of":null,"corrections":[],"dates":"Comments must be received on or before October 9, 2026.","disposition_notes":null,"docket_ids":["EPA-HQ-OW-2025-0322","FRL 11132.1-04-OW"],"dockets":[{"supporting_documents":[{"title":"U.S. Environmental Protection Agency and Department of the Army; Memorandum on POH-2023-00187","document_id":"EPA-HQ-OW-2025-0322-0108"},{"title":"U.S. Environmental Protection Agency; EPA Policy for the Administration of Environmental Programs on Indian Reservations (EPA Indian Policy)","document_id":"EPA-HQ-OW-2025-0322-0105"},{"title":"U.S. Environmental Protection Agency; Clean Water Act Approved Jurisdictional Determinations","document_id":"EPA-HQ-OW-2025-0322-0103"},{"title":"U.S. Office of Management and Budget; Circular A-4: Regulatory Analysis","document_id":"EPA-HQ-OW-2025-0322-0098"},{"title":"U.S. Department of the Army and Environmental Protection Agency; Memorandum of Agreement: Federal Enforcement for the Section 404 Program of the Clean Water Act","document_id":"EPA-HQ-OW-2025-0322-0094"},{"title":"U.S. Army Corps of Engineers; Corps of Engineers Wetlands Delineation Manual. Wetlands Research Program Technical Report Y-87-1","document_id":"EPA-HQ-OW-2025-0322-0091"},{"title":"Cowardin et al.; Classification of wetlands and deepwater habitats of the United States","document_id":"EPA-HQ-OW-2025-0322-0076"},{"title":"Alaska Department of Environmental Conservation (ADEC); Alaska Pollutant Discharge Elimination System (APDES) Capacity Building Plan","document_id":"EPA-HQ-OW-2025-0322-0074"},{"title":"Tangen and Bansal; Soil Organic Carbon Stocks and Sequestration Rates of Inland, Freshwater Wetlands: Sources of Variability and Uncertainty.","document_id":"EPA-HQ-OW-2025-0322-0068"},{"title":"Tang et al.; Impact of Size and Location of Wetlands on Watershed-Scale Flood Control","document_id":"EPA-HQ-OW-2025-0322-0067"}],"agency_name":"EPA","documents":[{"comment_count":0,"comment_start_date":"2026-09-09","updated_at":"2026-09-09T09:56:51.492-04:00","comment_url":"https://www.regulations.gov/commenton/EPA-HQ-OW-2025-0322-15447","allow_late_comments":false,"id":"EPA-HQ-OW-2025-0322-15447","comment_end_date":"2026-10-10","regulations_dot_gov_open_for_comment":true}],"supporting_documents_count":124,"id":"EPA-HQ-OW-2025-0322","title":"Updated Definition of Waters of the United States"}],"document_number":"2026-18317","effective_on":null,"end_page":57301,"executive_order_notes":null,"executive_order_number":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2026/09/09/2026-18317.xml","html_url":"https://www.federalregister.gov/documents/2026/09/09/2026-18317/updated-definition-of-waters-of-the-united-states","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/2026-18317?publication_date=2026-09-09","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2026-09-09/2026-18317/mods.xml","not_received_for_publication":null,"page_length":18,"page_views":{"count":1120,"last_updated":"2026-09-09 20:15:03 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2026-09-09/pdf/2026-18317.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2026-18317.pdf?1788871515","publication_date":"2026-09-09","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2026/09/09/2026-18317.txt","regulation_id_number_info":{"2040-AG44":{"issue":"202504","html_url":"https://www.federalregister.gov/regulations/2040-AG44/final-clarifying-definition-of-waters-of-the-united-states-","title":"Final Clarifying Definition of \"Waters of the United States\"","xml_url":"http://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202504&RIN=2040-AG44&operation=OPERATION_EXPORT_XML","priority_category":"Other Significant"}},"regulation_id_numbers":["2040-AG44"],"regulations_dot_gov_info":{"supporting_documents":[{"title":"U.S. Environmental Protection Agency and Department of the Army; Memorandum on POH-2023-00187","document_id":"EPA-HQ-OW-2025-0322-0108"},{"title":"U.S. Environmental Protection Agency; EPA Policy for the Administration of Environmental Programs on Indian Reservations (EPA Indian Policy)","document_id":"EPA-HQ-OW-2025-0322-0105"},{"title":"U.S. Environmental Protection Agency; Clean Water Act Approved Jurisdictional Determinations","document_id":"EPA-HQ-OW-2025-0322-0103"},{"title":"U.S. Office of Management and Budget; Circular A-4: Regulatory Analysis","document_id":"EPA-HQ-OW-2025-0322-0098"},{"title":"U.S. Department of the Army and Environmental Protection Agency; Memorandum of Agreement: Federal Enforcement for the Section 404 Program of the Clean Water Act","document_id":"EPA-HQ-OW-2025-0322-0094"},{"title":"U.S. Army Corps of Engineers; Corps of Engineers Wetlands Delineation Manual. Wetlands Research Program Technical Report Y-87-1","document_id":"EPA-HQ-OW-2025-0322-0091"},{"title":"Cowardin et al.; Classification of wetlands and deepwater habitats of the United States","document_id":"EPA-HQ-OW-2025-0322-0076"},{"title":"Alaska Department of Environmental Conservation (ADEC); Alaska Pollutant Discharge Elimination System (APDES) Capacity Building Plan","document_id":"EPA-HQ-OW-2025-0322-0074"},{"title":"Tangen and Bansal; Soil Organic Carbon Stocks and Sequestration Rates of Inland, Freshwater Wetlands: Sources of Variability and Uncertainty.","document_id":"EPA-HQ-OW-2025-0322-0068"},{"title":"Tang et al.; Impact of Size and Location of Wetlands on Watershed-Scale Flood Control","document_id":"EPA-HQ-OW-2025-0322-0067"}],"regulatory_plan":{"html_url":"https://www.federalregister.gov/regulations/2040-AG44/final-clarifying-definition-of-waters-of-the-united-states-","title":"Final Clarifying Definition of \"Waters of the United States\""},"comments_count":0,"agency_id":"EPA","comments_url":"https://www.regulations.gov/docketBrowser?rpp=50&so=DESC&sb=postedDate&po=0&dct=PS&D=EPA-HQ-OW-2025-0322","supporting_documents_count":124,"docket_id":"EPA-HQ-OW-2025-0322","document_id":"EPA-HQ-OW-2025-0322-15447","regulation_id_number":"2040-AG44","title":"Updated Definition of Waters of the United States","checked_regulationsdotgov_at":"2026-09-10T01:55:04Z"},"regulations_dot_gov_url":"http://www.regulations.gov/commenton/EPA-HQ-OW-2025-0322-15447","significant":true,"signing_date":null,"start_page":57284,"subtype":null,"title":"Updated Definition of “Waters of the United States”","toc_doc":"Updated Definition of Waters of the United States","toc_subject":null,"topics":["Administrative practice and procedure","Environmental protection","Navigation (water)","Water pollution control","Waterways"],"type":"Proposed Rule","volume":91}