The scope of waters covered by the federal Clean Water Act - called Waters of the U.S. - is one of the most complex, controversial, and contentious issues in environmental policy. Waters of the U.S. has been the focus of Supreme Court rulings, lobbying and litigation by stakeholders, and rulemakings by the U.S. Environmental Protection Agency under the Obama and Trump administrations. The history is explained in this episode with Ken Kopocis, the head of water at EPA under President Obama, and Dave Ross, the head of water at EPA under President Trump and now a partner at Troutman Pepper. Ken and Dave discuss the difficulty of defining Waters of the U.S., misconceptions and distortions of their respective rulemakings, their approach to working with stakeholders, the influence of politics on the issue, and if there could ever be a compromise.