	Introduction

On May 27, 2015, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) jointly announced a final rule defining the scope of waters protected under the Clean Water Act (CWA). The rule revises regulations that have been in place for more than 25 years. Revisions were proposed in March 2014 in light of Supreme Court rulings in 2001 and 2006 that interpreted the regulatory scope of the CWA more narrowly than the agencies and lower courts were then doing, and created uncertainty about the appropriate scope of waters protected under the CWA. On October 9, 2015, a federal court issued an order to stay implementation of the rule nationwide, pending further developments (see " Recent Developments "). Waters that are jurisdictional are subject to the multiple regulatory requirements of the CWA: standards, discharge limitations, permits, and enforcement. Non-jurisdictional waters, in contrast, are not subject to these federal legal requirements. According to the agencies, the new rule—which they now refer to as the Clean Water Rule—revises the existing administrative definition of "waters of the United States" in regulations consistent with legal rulings—especially the recent Supreme Court cases—and science concerning the interconnectedness of tributaries, wetlands, and other waters to downstream waters and effects of these connections on the chemical, physical, and biological integrity of downstream waters. The rule is particularly focused on clarifying the regulatory status of surface waters located in isolated places in a landscape (the types of waters with ambiguous jurisdictional status following the Supreme Court's 2001 ruling in SWANCC ) and small streams, rivers that flow for part of the year, and nearby wetlands (the types of waters affected by the Court's 2006 ruling in Rapanos ). Waters That Are Categorically Jurisdictional

Under the first section of the revised regulation, the following six categories of waters would be jurisdictional by rule without additional or case-specific analysis:
Waters susceptible to interstate commerce, known as traditional navigable waters (no change from existing rules or the 2014 proposal); All interstate waters, including interstate wetlands (no change from existing rules or the 2014 proposal); The territorial seas (no change from existing rules or 2014 the proposal);
Tributaries of the above waters if they meet the definition of "tributary" (these waters are jurisdictional under existing rules, but the term "tributary" is newly defined in the proposed and final rule); Impoundments of the above waters or a tributary, as defined in the rule (no change from existing rules or the 2014 proposal); and All waters, including wetlands, ponds, lakes, oxbows, and similar waters, that are adjacent to a water identified in the above categories (these are considered jurisdictional under the final rule because the agencies conclude that they have a significant nexus to a traditional navigable water, interstate water, or the territorial seas; the final rule provides a revised definition that for the first time sets limits on what will be considered "adjacent"). Nevertheless, the agencies acknowledge that the rule would increase the categorical assertion of CWA jurisdiction, when compared to a baseline of current practices under the 2003 and 2008 EPA-Corps guidance. This results in part from the agencies' expressly declaring some types of waters categorically jurisdictional and not requiring case-specific evaluation of them (such as all waters adjacent to a jurisdictional water). The agencies believe that the rule does not protect any new types of waters that have not been protected historically (that is, beyond the existing regulations, which the new rule will replace) and that it does not exceed the CWA's coverage. That is, while it would enlarge categorical jurisdiction beyond that under the 2003 and 2008 EPA-Corps guidance, which the agencies believe was narrower than is justified by science and the law, they believe that it would not enlarge jurisdiction beyond what is consistent with the Supreme Court's current reading of jurisdiction. In an Economic Analysis document accompanying the final rule, the agencies estimate that the new rule will result in 2.84%-4.65% more positive assertions of jurisdiction over U.S. waters, compared with current field practice. Congressional interest in the rule has been strong since the proposed rule was announced in March 2014. EPA and Corps officials believe that the final rule responds to those criticisms. The agencies' intention has been to clarify the rules and make jurisdictional determinations more predictable, less ambiguous, and more timely. Some stakeholders believe that the agencies largely succeeded in that objective, while others do not. Recent Developments

Legal challenges to the Clean Water Rule were filed in multiple federal courts soon after it was announced. These lawsuits, filed by industry groups, more than half of the states, and several environmental groups (nearly 90 plaintiffs so far), will test whether the agencies' interpretation of CWA jurisdiction is consistent with the Supreme Court's rulings and whether the rule complies with substantive and procedural requirements of the CWA and other laws.
On May 27, 2015, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) jointly announced a final rule defining the scope of waters protected under the Clean Water Act (CWA). The rule revises regulations that have been in place for more than 25 years. Revisions are being made in light of 2001 and 2006 Supreme Court rulings that interpreted the regulatory scope of the CWA more narrowly than the agencies and lower courts were then doing, and created uncertainty about the appropriate scope of waters protected under the CWA.
According to the agencies, the new rule revises the existing administrative definition of "waters of the United States" consistent with the CWA, legal rulings, the agencies' expertise and experience, and science concerning the interconnectedness of tributaries, wetlands, and other waters and effects of these connections on the chemical, physical, and biological integrity of downstream waters. Waters that are "jurisdictional" are subject to the multiple regulatory requirements of the CWA. Non-jurisdictional waters are not subject to those requirements.
This report describes the final revised rule—which the agencies refer to as the Clean Water Rule. It includes a table comparing the existing regulatory language that defines "waters of the United States" with the revisions. The rule is particularly focused on clarifying the regulatory status of surface waters located in isolated places in a landscape. It does not modify some categories of waters that are jurisdictional under existing rules (traditional navigable waters, interstate waters and wetlands, the territorial seas, and impoundments). The rule also lists waters that would not be jurisdictional, such as prior converted cropland and certain ditches. It makes no change to existing statutory exclusions, such as CWA permit exemptions for normal farming and ranching activities. The rule will replace EPA-Corps guidance that was issued in 2003 and 2008, which has guided agency interpretation of the Court's rulings but also has caused considerable confusion. Much of the controversy since the Supreme Court rulings has focused on the degree to which isolated waters and small streams are jurisdictional. Under the EPA-Corps guidance, many of these waters have required case-specific evaluation to determine if jurisdiction applies. Under the final rule, some of these waters would continue to need case-specific review, but fewer than under the existing agency guidance documents. The final rule also explicitly excludes specified waters from the definition of "waters of the United States" (e.g., prior converted croplands, stormwater management systems, and groundwater).
Changes in the final rule would increase the categorical assertion of CWA jurisdiction, in part as a result of expressly declaring some types of waters jurisdictional by rule (such as all waters adjacent to a jurisdictional water), making these waters subject to the act's permit and other requirements if pollutant discharges occur. Nevertheless, the agencies believe that the rule does not exceed the CWA's lawful coverage or protect new types of waters that have not been protected historically (i.e., under existing rules that the new rule will replace). While it would enlarge jurisdiction beyond that under the existing EPA-Corps guidance, they believe that it would not enlarge jurisdiction beyond what is consistent with the Supreme Court's current reading of jurisdiction and would reduce jurisdiction over some waters, as a result of exclusions and exemptions. The agencies estimate that the new rule will result in approximately 3-5% more positive assertions of jurisdiction over U.S. waters, compared with current field practice.
Congressional interest in the rule has been strong since it was proposed in 2014 and has continued in the 114th Congress. The agencies contend that the final rule responds to criticisms of the proposed rule. Their stated intention has been to clarify the rules and make jurisdictional determinations more predictable, less ambiguous, and more timely. Some stakeholders believe that the agencies largely succeeded in that objective, while others do not. Challenges to the rule were filed in multiple federal district and appellate courts by industry groups, more than half of the states, and several environmental groups. The rule became effective on August 28, 2015, but on October 9, 2015, a federal court blocked the rule's implementation nationwide. The legal question of which federal court should review the challenges to the rule remains in limbo.