This paper documents the impact of different drinking water violations on infant health outcomes at a national level net of the impact of existing regulations. It shows that while avoidance behavior such as buying drinking water is significant, it cannot fully offset the health impact of water contaminants. Moreover, consumers only respond to the most salient contaminants and fail to appreciate the risks associated with water contamination. Once exposure has occurred medica, medical treatment is not sufficient to compensate for the damage to fetal health. This paper also shows that enforcement activities can be very effective at minimizing exposure even when enforcement is informal and does not make use of the full extent of the law.