This paper exploits China’s culture-oriented institutional reform as a quasinatural experiment to examine the impact of cultural policies on water pollution. Using a difference-in-differences approach with city-level panel data from 2003 to 2020, we find that the reform leads to a significant reduction in water pollution in pilot cities. Heterogeneity analysis indicates that the effect is more pronounced in cities with better economic performance, higher administrative status, richer tourism resources, and more abundant human capital. The reform prompts a shift in local industrial structure toward less-polluting sectors, with a marked contraction in pollution-intensive activities. It also strengthens local environmental regulation and enhances green innovation, thereby contributing to pollution reduction. Our findings highlight the spillover environmental effects of policies not explicitly designed for environmental purposes.