This Article explores the administrative reform potential that exists for integrating new knowledge about ecosystem services into Clean Water Act (CWA) regulatory programs as an example for all environmental laws. Part II of the Article reviews the relevant general rules of federal administrative law governing agency interpretation of the policy space available under statutory authority for integrating new science into decision making. Part III then explores the strategies an agency such as EPA can use under those rules to integrate the concept of ecosystem services into regulatory programs by searching for statutory provisions to support what I call "direct protection" authority and "performance metric" authority. Part IV of the Article turns to the dredge and fill permit program of section 404 of the CWA and the water quality standards and total maximum daily load (TMDL) program of section 303 of the CWA as its case studies, showing how opportunities for and obstacles to the two integration strategies arise in the structure and text of the statute. The Article closes with some thoughts on a more overarching agenda for working ecosystem services into existing federal environmental protection programs.