Clean water is essential for human survival. However, a large proportion of people do not have access to clean water in Vietnam. Approximately only 23% of the population had access to piped water in 2006. This study measures the effect of piped water on household welfare using difference-in-differences estimators and panel data from Vietnam Household Living Standard Surveys. It found that the effect of piped water on household income and working efforts are positive, but are small and not statistically significant. Similarly, the effect of piped water on the sickness of household members is negative, but not statistically significant.