Revisions to Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems

April 8, 2024 Bruno Pigott Acting Assistant Administrator Office of Water U.S. Environmental Protection Agency 1200 Pennsylvania Avenue, N.W. Washington, D.C. 20460 Re: Comments on Revisions to the Unregulated Contaminant Monitoring Rule (UCMR 5); Methods and Webinar of UCMR 6; EPA-HQ-OW-2023-0469; FRL-10857-04-OW Dear Acting Assistant Administrator Pigott: We, the undersigned organizations representing a coalition of companies, trade associations, and other stakeholders from across the economy, appreciate the opportunity to provide comments on the proposed revisions to the Unregulated Contaminants Monitoring Rule test methods. We support gathering additional scientifically valid data on the national occurrence of select PFAS in drinking water. Ensuring the validity and appropriateness of the analytical methods used should be of the highest importance. Our customers, employees, and communities depend on clean water for a better quality of life and economic growth. This information is a critical input in determining whether and how EPA should regulate particular contaminants for treatment. The following are our priorities for your consideration: •Ensure that costs are included and considered when developing and approving targeted test methods as required under the Safe Drinking Water Act. •Focus resources on developing validated analytical methods for detecting PFAS chemistries included in current and ongoing regulatory actions in drinking water for this and future monitoring efforts (e.g., TRI and TSCA requirements). •Analyze each PFAS chemistry or subcategory using targeted analysis given variations in physical, chemical, and toxicological properties. •Ensure that the method performance sensitivity, selectivity, accuracy, and precision attainable for each contaminant meets the highest standards. These analytical methods will likely be used to support potentially costly rulemaking efforts and the analytical methods must be appropriate. •Provide detailed evaluation of laboratory capacity to complete needed testing under agreed methods. The business community supports appropriate water monitoring data collection to assess unregulated contaminants. Such information remains essential to ensuring that federal interventions are prioritized appropriately and are based on the best science and risk. Sincerely, Alliance for Chemical Distribution American Chemistry Council TRSA - The Linen, Uniform and Facility Services Association U.S. Chamber of Commerce

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