Mitigating PFAS Contamination: Assessing the Impact of California's Legislation from 2018-2022 on Drinking Water Quality

This study evaluates the impact of California’s specific per- and polyfluoroalkyl substances (PFAS) legislation on perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) contamination levels in public drinking water. We conducted a comparative statistical analysis using data from the EPA’s Unregulated Contaminant Monitoring Rules (UCMRs), specifically UCMR 3 and UCMR 5, to assess PFOA and PFOS levels in active public water systems during the pre-legislation period (2017) and the post-legislation period (2023). Levene's test was performed to assess differences in variances, followed by unpaired and Welch’s t-tests to compare mean PFAS concentrations between the two time periods. Our results indicate a significant decline in both PFOA and PFOS levels post-legislation, suggesting that robust state-level regulatory measures can effectively reduce PFAS contamination. These findings highlight the potential for California’s comprehensive approach to serve as a model for federal and national policy aimed at mitigating PFAS exposure and protecting public health.