Security-related activities undertaken by Environmental Protection Agency (EPA) and the water sector have fallen into five general categories, including: (i) establishing an information center for drinking water alerts or incidents, (ii) developing vulnerability assessment tools, (iii) identifying actions to minimize vulnerabilities, (iv) revising emergency operations plans, and (v) supporting research on biological and chemical contaminants considered to be potential weapons of mass destruction. This chapter addresses terrorism issues relevant to the water sector through the following topics: the need for Emergency Response Planning, assessing the risk, the planning process, training of personnel, emergency communication, emergency response, and the emergency recovery process. An application section completes the chapter with six Illustrative Examples related to the general subject of water security and water utility threat assessment.