PFAS Policies and Reductions in Drinking Water Contamination Across the United States: Incorporated Policy Perspectives from Los Angeles Residents.

Background: Many U.S. states have adopted per- and polyfluoroalkyl substances (PFAS)-related policies, but evidence on whether these actions reduce detections in drinking water is limited. Methods: We conducted a nationwide analysis of the EPA Unregulated Contaminant Monitoring Rule (UCMR) and a community study in Los Angeles (LA). State-wide PFAS policies correlated with PFAS detections in public water systems (n = 56,856) using UCMR3 (2013-2015) and UCMR5 (2023-2025) for six PFAS (PFBS, PFHpA, PFHxS, PFNA, PFOA, PFOS). We examined associations between detections or changes in detections and two metrics: (1) total PFAS policy counts and (2) the proportion of water-related PFAS policies. In LA, we conducted focus groups/interviews (n = 29) and tested a 55-PFAS panel in household tap water (n = 23; Pasadena/Torrance n = 9; Central/Southeast LA n = 14). Results: Total policy counts were not associated with lower PFAS detection in UCMR5, except for a borderline reduction in PFBS (β = -0.0003, p = 0.06). A higher proportion of water-focused policies was associated with increased odds of PFAS detection, with significant associations for PFBS (OR = 3.79, 95% CI: 2.83-5.10), PFHpA (2.66, 1.64-4.33), PFHxS (3.10, 2.10-4.62), and PFOS (3.37, 2.41-4.71). Similar results were observed for changes in detection. In LA, residents reported distrust in tap water, low PFAS awareness, and emphasized independent testing, subsidized filtration, and clearer communication. Conclusions: Greater concentrations of water-focused policies were linked to increased PFAS detections, likely reflecting enhanced surveillance or responses in high-burden states. Community perspectives highlight that policy also requires trust, transparency, and resources.