Abstract The goal of achieving “sustainable development” has been embraced by a wide range of stakeholders interested in protecting both the environment and the economy in the United States and globally. The Clean Water Act (“CWA” or the “Act”) includes important regulatory provisions that contemplate the application of sustainable development principles. Yet implementing those programs often raises substantial debate about what sustainable development means, what course of action it requires, and the availability and adequacy of tools to measure or predict whether a given level of use or development is sustainable. Failure to confront those questions can lead to imprudent or wasteful decisions. This paper first will briefly describe the ongoing evolution of sustainable development concepts in the United States, with particular focus on the recommendations of the President’s Council on Sustainable Development. Then, it will examine the applicability of those concepts to two important Clean Water Act regulatory programs — the §316(b) regulatory program for cooling water intake structures and the state water quality standards program — both of which are now under evaluation.