Has Surface Water Quality Improved Since the Clean Water Act?

On the fortieth anniversary of the Clean Water Act this paper reports the first quantitative assessment of the aggregate trends in water quality in the U.S. using a single standard over the years 1975 to 2011. The analysis suggests that fresh water lakes for the nation as a whole are about at the same quality levels as they were in 1975. In short, viewed in the aggregate, nothing has changed. An assessment of the factors influencing the aggregates also suggests that water quality appears to be affected by the business cycle. This result calls into question the simple descriptions of the change in environmental quality with economic growth that are associated with the Environmental Kuznets Curve.