{"abstract":"The U.S. Environmental Protection Agency (EPA or agency) is proposing the sixth Unregulated Contaminant Monitoring Rule (UCMR 6). Under the Safe Drinking Water Act (SDWA), the UCMR program gathers data about unregulated contaminant occurrence in drinking water. The proposed UCMR 6 would require public water systems (PWSs) to collect national occurrence data for seven ultrashort organofluorine compounds (including certain PFAS), three pesticide metabolites, 13 semivolatile organic compounds, and seven purgeable organic compounds. Subject to the availability of appropriations, the EPA will require all community and non-transient non-community water systems (CWSs and NTNCWSs) serving 3,300 or more people, and a representative sample of PWSs serving fewer than 3,300 people, to conduct monitoring. These contaminants are not currently subject to national primary drinking water regulations (NPDWRs), and the EPA is proposing to require the collection of drinking water occurrence data to inform agency decisions. The data collected will be publicly available. The EPA is also announcing two public meetings (via webinar) to discuss this proposal of the sixth Unregulated Contaminant Monitoring Rule (UCMR 6).","action":"Proposed rule; notice of public meeting.","agencies":[{"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/2026/07/01/2026-13263.html","cfr_references":[{"chapter":null,"citation_url":null,"part":"141","title":40}],"citation":"91 FR 39952","comment_url":"http://www.regulations.gov/commenton/EPA-HQ-OW-2023-0469-0097","comments_close_on":"2026-07-31","correction_of":null,"corrections":[],"dates":"Comments must be received on or before August 31, 2026. Comments on the information collection provisions of the proposed rule under the Paperwork Reduction Act (PRA) must be received by the Office of Management and Budget's Office of Information and Regulatory Affairs (OMB-OIRA) on or before July 31, 2026. Please refer to the PRA section under \"Statutory and Executive Order Reviews\" in this preamble for specific instructions. Public meeting: the EPA will hold two identical virtual, public meetings on August 11, 2026 and August 12, 2026 at https://www.epa.gov/dwucmr/unregulated-contaminant-monitoring-rule- ucmr-meetings-and-materials. Please refer to the SUPPLEMENTARY INFORMATION section for additional information on the public meetings.","disposition_notes":null,"docket_ids":["EPA-HQ-OW-2023-0469","FRL-10857-03-OW"],"dockets":[{"supporting_documents":[{"title":"Information Collection Request for the Proposed Unregulated Contaminant Monitoring Rule (UCMR 6) Supporting Statement","document_id":"EPA-HQ-OW-2023-0469-0143"},{"title":"Request of the Governors of New Jersey, Delaware, Illinois, Maryland, Michigan, Wisconsin, and Connecticut under 42 U.S.C. § 300j-4(a)(2)(B)(ii) that EPA Include Microplastics in the Forthcoming Unregulated Contaminant Monitoring Rule 6 List","document_id":"EPA-HQ-OW-2023-0469-0137"},{"title":"Standard Practice for Preparation of Water Samples with High, Medium, or Low Suspended Solids for Identification and Quantification of Microplastic Particles and Fibers Using Raman Spectroscopy, IR Spectroscopy, or Pyrolysis GC/MS","document_id":"EPA-HQ-OW-2023-0469-0135"},{"title":"Chlorpyrifos: Third Revised Human Health Risk Assessment for Registration Review","document_id":"EPA-HQ-OW-2023-0469-0122"},{"title":"EPA's Per- and Polyfluoroalkyl Substances (PFAS) Action Plan","document_id":"EPA-HQ-OW-2023-0469-0121"},{"title":"2019 Analysis of State Drinking Water Programs' Resources and Needs: Addressing Emerging Issues and State Specificity in Program Implementation","document_id":"EPA-HQ-OW-2023-0469-0108"},{"title":"Instructions for Preparing a Ground Water Representative Monitoring Plan for the Unregulated Contaminant Monitoring Rule","document_id":"EPA-HQ-OW-2023-0469-0107"},{"title":"Food and Water Watch Microplastics Petition EPA Response Letter","document_id":"EPA-HQ-OW-2023-0469-0103"},{"title":"Pre-Proposal Webinar Summary and Slides","document_id":"EPA-HQ-OW-2023-0469-0098"},{"title":"EPA Method 521 – Determination of Nitrosamines in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography with Large Volume Injection and Chemical Ionization Tandem Mass Spectrometry (MS/MS). Version 1.0","document_id":"EPA-HQ-OW-2023-0469-0061"}],"agency_name":"EPA","documents":[{"comment_count":3744,"comment_start_date":"2026-07-01","updated_at":"2026-07-27T01:55:51.075-04:00","comment_url":"https://www.regulations.gov/commenton/EPA-HQ-OW-2023-0469-0097","allow_late_comments":false,"id":"EPA-HQ-OW-2023-0469-0097","comment_end_date":"2026-09-01","regulations_dot_gov_open_for_comment":true}],"supporting_documents_count":133,"id":"EPA-HQ-OW-2023-0469","title":"Revisions to Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems"}],"document_number":"2026-13263","effective_on":null,"end_page":39973,"executive_order_notes":null,"executive_order_number":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2026/07/01/2026-13263.xml","html_url":"https://www.federalregister.gov/documents/2026/07/01/2026-13263/revisions-to-establish-the-sixth-unregulated-contaminant-monitoring-rule-ucmr-6-for-public-water","images":{"EP01JY26.017":{"large":"https://img.federalregister.gov/EP01JY26.017/EP01JY26.017_large.png","medium":"https://img.federalregister.gov/EP01JY26.017/EP01JY26.017_medium.png","original_size":"https://img.federalregister.gov/EP01JY26.017/EP01JY26.017_original_size.png"}},"images_metadata":{"EP01JY26.017":{"large":{"identifier":"EP01JY26.017","content_type":"image/png","size":62901,"width":821,"sha":"87b284920e94c269bcd3ff802778249a","url":"https://img.federalregister.gov/EP01JY26.017/EP01JY26.017_large.png","height":672},"medium":{"identifier":"EP01JY26.017","content_type":"image/png","size":26958,"width":518,"sha":"cf027e105089cd30dc36e85b5c2ef3ae","url":"https://img.federalregister.gov/EP01JY26.017/EP01JY26.017_medium.png","height":424},"original_size":{"identifier":"EP01JY26.017","content_type":"image/png","size":44431,"width":1957,"sha":"4fd76c600e1342feae462cc93b822505","url":"https://img.federalregister.gov/EP01JY26.017/EP01JY26.017_original_size.png","height":1602}}},"json_url":"https://www.federalregister.gov/api/v1/documents/2026-13263?publication_date=2026-07-01","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2026-07-01/2026-13263/mods.xml","not_received_for_publication":null,"page_length":22,"page_views":{"count":2397,"last_updated":"2026-07-27 14:15:04 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2026-07-01/pdf/2026-13263.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2026-13263.pdf?1782823514","publication_date":"2026-07-01","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2026/07/01/2026-13263.txt","regulation_id_number_info":{"2040-AG33":{"issue":"202504","html_url":"https://www.federalregister.gov/regulations/2040-AG33/revisions-to-establish-the-sixth-unregulated-contaminant-monitoring-rule-ucmr-6-for-public-water-sys","title":"Revisions to Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems","xml_url":"http://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202504&RIN=2040-AG33&operation=OPERATION_EXPORT_XML","priority_category":"Other 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