The Institute of Medicine's Roundtable on Environmental Health Sciences, Research, and Medicine was established in 1988 as a mechanism for bringing the various stakeholders together to discuss environmental health issues in a neutral setting. The members of the Roundtable on Environmental Health Sciences, Research, and Medicine come from academia, industry, and government. Their perspectives range widely and represent the diverse viewpoints of researchers, federal officials, and consumers. They meet, discuss environmental health issues that are of mutual interest, and bring others together to discuss these issues as well. For example, they regularly convene workshops to help facilitate discussion of a particular topic. The Rountable's fifth national workshop entitled From Source Water to Drinking Water: Ongoing and Emerging Challenges for Public Health continued the theme established by previous Roundtable workshops, looking at rebuilding the unity of health and the environment. This workshop summary captures the discussions and presentations by the speakers and participants, who identified the areas in which additional research was needed, the processes by which changes could occur, and the gaps in our knowledge.