Clean water makes your dirty: water supply and sanitation behaviour in the Philippines

Water supply improvements are a frequent policy response to endemic diarrhea in developing countries. However, these interventions may unintentionally cause commu-nity sanitation to worsen. Such a response could occur because improved water supplies mitigate the consequences of poor sanitation for the community. Since sanitary behav-iors have large externalities, the negative health impact of this endogenous response may overwhelm the direct benefit of clean water. This paper shows how the expan-sion of municipal piped water in Metro Cebu, the Philippines has exacerbated public defecation, garbage disposal, and diarrhea. I rely on instrumental variables and house-hold fixed effects to rule out non-causal explanations for these results, and find that a neighborhood’s complete adoption of piped water increases the likelihood of observing excrement or garbage by 15-30 percent. Such a change increases diarrhea incidence by 35-40 percent