This article reviews the regulation of lead in drinking water, highlighting its epidemiological, engineering, and ethical aspects with a focus on the Flint water crisis. We first discuss water quality policy and its implementation with a focus on lead contamination of water, primarily from pipe systems between a water treatment facility and a tap. We then discuss physicians' roles and ethical responsibilities regarding safe drinking water using a human rights framework. We argue that physicians can play an important role in safeguarding drinking water in their communities by being vigilant, honoring the community's trust in them, and warning, educating, and empowering patients and broader communities so as to protect tap water safety and public health.