To raise drinking water accessibility and safety in rural China, the Chinese government launched the rural drinking water program in 1980s. As part of the program, many water plants are built up in rural areas to supply tap water to rural residents. This policy intervention provides us a unique opportunity to examine the impact of access to tap water during early life (from one year before birth to five years old) on children’s human capital development in the medium run. By exploiting the variation in the timing of tap water’s entry into different communities, we calculate early life years of exposure to tap water at community level for each child. We find that one additional year of exposure to tap water during early life increases standardized cognitive test score by 0.128 standard deviation and health index by 0.106 standard deviation for girls aged 10-17. No significant causal effect is detected on boys’ cognitive abilities or health outcomes. The findings suggest that early life exposure to improved public facilities could have large and lasting effect on human capital development.