This paper evaluates the impact of the anti-corruption campaign launched in 2013 on water quality in China. Provinces are assigned to treatment and control groups according to exposure level to anti-corruption campaign, enabling the im- plementation of a difference-in-difference strategy. Using surface water quality data from 2006 to 2015, we find evidence that stronger exposure to anti-corruption cam- paign can improve water quality. The results are robust at both the monitoring station level a