This paper examines how water filtration and distribution helped reduce mortality during a cholera outbreak. Using household water contract records and individual mortality data, I analyze the impact of filtered water with an event study approach. The results show that having access to filtered water at home greatly reduced the risk of death. This suggests that water filtration and distribution were key public health measures in lowering mortality from waterborne diseases in the 19th and early 20th centuries. Improvements in urban water systems could have played a major role in the decline of cholera outbreaks and mortality during this period.