Nonpoint source pollution is the biggest threat to water quality in the United States today. This Article argues for stronger federal controls over nonpoint source pollution. It begins by examining the history of water quality regulation in the United States, including the passage and amendment of the Clean Water Act and the evolving definition of “navigable waters” over time. The Article then discusses recent rulemaking and litigation developments, including the Clean Water Rule, the Navigable Waters Protection Rule, and the County of Maui, Hawaii v. Hawaii Wildlife Fund case. It offers three recommendations. First, the Article calls for a congressional amendment to the Clean Water Act to require binding controls on nonpoint source pollution. Second, recognizing that an amendment to the Clean Water Act may not be politically viable, it offers an approach for controlling nonpoint source pollution through an amendment to the Safe Drinking Water Act. Finally, it identifies tools that interested states, local governments, and citizens’ groups can utilize to take action on nonpoint source pollution under existing law. This Article concludes that reductions in nonpoint source pollution will lead to significant improvements in the water quality of our nation’s lakes, rivers, wetlands, and coastal areas, to the benefit of human and environmental health.