This project provides WERF subscribers with a state-of-knowledge report that is a synthesis of existing work and provides guidance on effective risk communication practices, public perception and message effectiveness. Communication principles are applicable to a wide variety of potential health and environmental risks; however, the report is written with a focus on trace organic compounds. Project findings are drawn from: 1) a focused literature review of communication materials published in the environmental industry; 2) documents describing risk communication practices in other industries (nuclear energy, chemical manufacturing and the pharmaceutical industry) which culminated in several "lessons learned" that are relevant to trace organic compounds; 3) coding and systematic analysis of approximately 25 recent media articles pertaining to trace organic compounds focused on vocabulary and imagery, key messages, and the articles' likely impact on the public; and 4) interviews with water and wastewater utility representatives to better understand their existing communication and outreach programs, interaction with the public and media and perspectives on communications needs. Principles described in this report can be used to convey a wide variety of messages to help municipalities better communicate with the media and public. Recommendations for utilities and ideas for future research specific to trace organic compounds are also provided.