Four hundred stakeholder meetings and one million comments later, the U.S. Environmental Protection Agency released the final Waters of the United States (WOTUS) rule on May 27, 2015. Response to the rule has been immediate, vocal, and varied across the political spectrum. Some environmental advocates have criticized the rule for what it explicitly excludes, arguing that the rule leaves out too many streams and wetlands. At the same time, industry and agriculture interests have decried the rule as federal overreach. Understanding the scope, vulnerabilities, and likely implementation of the WOTUS rule is central for practitioners. What does the Clean Water Act (CWA) actually cover under the final rule? Are there activities that may be subject to the CWA for the first time or no longer covered? Where do the uncertainties lie? What legal challenges might advocates bring against the rule? Will the federal government have new tools to extend federal jurisdiction, and how will states react? On June 8, 2015, the Environmental Law Institute convened a panel of experts to explore this vitally important new rule. In this Dialogue, we present a transcript of the discussion, which has been edited for style, clarity, and space considerations.