Wastewater Treatment Works Security Act of 2003

Wastewater Treatment Works Security Act of 2003 - Amends the Federal Water Pollution Control Act to authorize the Administrator of the Environmental Protection Agency (EPA) to make grants to a State, municipality, or intermunicipal or interstate agency to conduct a vulnerability assessment of a publicly owned treatment works and implement security enhancements for such facilities upon completion of the assessment.Authorizes the Administrator to: (1) provide technical guidance and assistance to small publicly owned treatment works (those serving a population of fewer than 20,000 persons) on conducting vulnerability assessments and implementing security enhancements; and (2) make grants to a nonprofit organization to improve vulnerability self-assessment methodologies and tools for publicly owned treatment works, including those that are part of a combined wastewater treatment and water supply system.