The Cost of “Forever”: Economic Implications of Per- and Polyfluoroalkyl Substances (PFAS) Mitigation in Drinking Water and Their Impact on Water Affordability

Regulating per- and polyfluoroalkyl substances (PFAS) has presented challenges for water managers and policymakers globally for over two decades. Estimated mitigation costs in drinking water in the United States of approximately 1. 5 billion USD highlight the magnitude of the issue. Little research is available to better understand how costs differ at a local level, where the costs are often incurred, or the associated impacts on affordability to households, who ultimately pay for such mitigation. To contribute to the topic, we use a dataset of 154 water agencies in California that are confronting PFAS treatment and analyze the impacts on production costs and affordability under four regulatory scenarios. Results suggest that while different available technologies lead to slightly different mitigation costs, regulatory stringency and degree to which source water is contaminated significantly impact costs, whose median increase is estimated to be approximately 0. 38/m3 (+119. 23%) in the least economically favorable situation. These costs translate into an average increase of 58. 39/month in household water expenditure, which can present affordability challenges for lower-income households as the affordability ratio exceeds 2. 5% in several instances. Results also suggest that communities of color, controlling for income, are associated with higher levels of potential PFAS exposure than white communities.