Total Maximum Daily Loads (TMDLs) to Stormwater Permits Handbook Christine Ruf, U.S. Environmental Protection Agency;Dean Maraldo, U.S. Environmental Protection Agency; Menchu Martinez, U.S. Environmental Protection Agency; Jamie Fowler, U.S. Environmental Protection Agency; Bob Newport, U.S. Environmental Protection Agency; Jack Faulk, U.S. Environmental Protection Agency Kellie DuBay, Tetra Tech, Inc., Jessica Koenig, Tetra Tech, Inc. U.S. Environmental Protection Agency Office of Water, (4503-T) 1200 Pennsylvania Avenue, NW Washington, DC 20004 ABSTRACT Stormwater runoff is a significant contributor to water quality impairments across the country, particularly runoff from developing and urbanized areas. Currently there are thousands of Clean Water Act (CWA) section 303(d) listed waters impaired for stormwater-source pollutants such as pathogens, nutrients, sediments and metals. To effectively address these impairments it is important to strengthen connections between two key federal programs under the CWA—the Total Maximum Daily Load (TMDL) program and the National Pollutant Discharge Elimination System (NPDES) stormwater permitting program. The U.S. Environmental Protection Agency (EPA) has recently developed a draft resource entitled TMDLs to Stormwater Permits Handbook (U.S. Environmental Protection Agency, 2008) to address challenges that are unique to TMDL development and implementation involving permitted stormwater discharges. The Handbook provides a reference for TMDL practitioners and stormwater permit writers on current approaches for developing more detailed stormwater-source wasteloadallocations, coordinating numeric wasteload allocations and NPDES stormwater permit requirements, and supporting TMDL implementation with a better understanding of the process to analyze and select stormwater best management practices (BMPs). The Handbook contains information to give TMDL practitioners and stormwater permit writers a better understanding of (1) cross-program regulatory requirements and programmatic processes; (2) current efforts to establish better cross-program connections; and (3) opportunities to further improve how the TMDL and NPDES stormwater programs interact to address stormwater- related water quality impairments. Real-world examples illustrate concepts and approaches for promoting improved implementation of TMDLs through stormwater permits. This paper will discuss key information, case studies and approaches contained in theHandbook. In addition, this paper will identify evolving issues and challenges as EPA and state TMDL practitioners and stormwater permit writers consider and test new approaches and strategies in the future. KEYWORDS Total Maximum Daily Load Program (TMDL), impaired waters, section 303(d), stormwater, water quality standards, National Pollutant Discharge Elimination System (NPDES) permits, 1226 TMDL 2009 Copyright ©2009 Water Environment Federation. All Rights Reserved.