Last year the Journal of Economic Perspectives published "US Water Pollution Regulation over the Past Half Century: Burning Waters to Crystal Springs?" by David A. Keiser and Joseph S. Shapiro. The abstract:
In the half century since the founding of the US Environmental Protection Agency, public and private US sources have spent nearly $5 trillion ($2017) to provide clean rivers, lakes, and drinking water (annual spending of 0.8 percent of US GDP in most years). Yet over half of rivers and substantial shares of drinking water systems violate standards, and polls for decades have listed water pollution as Americans' number one environmental concern. We assess the history, effectiveness, and efficiency of the Clean Water Act and Safe Drinking Water Act and obtain four main conclusions. First, water pollution has fallen since these laws were passed, in part due to their interventions. Second, investments made under these laws could be more cost effective. Third, most recent studies estimate benefits of cleaning up pollution in rivers and lakes that are less than the costs, though these studies may undercount several potentially important types of benefits. Analysis finds more positive net benefits of drinking water quality investments. Fourth, economic research and teaching on water pollution are relatively uncommon, as measured by samples of publications, conference presentations, and textbooks.