Since little is known about the long-run effect of treated water, we examine the educational benefit to rural youth in China from a major water treatment program started in the 1980s. By employing a data set covering two decades and encompassing more than 4700 individuals between ages 18 and 25, we find that, on average, the program increased the completed grades of education of rural youth by 1.1 years. Moreover, the effect was highly heterogeneous across gender and age of exposure. Rural girls