In response to the terrorist attacks of 9/11, Congress passed the Public Health, Security and Bioterrorism Act, which required all water utilities serving more than 3,300 people to compile a vulnerability assessment of treatment operations and develop security plans to protect these systems against terrorist attack. Charleston Water System submitted its Vulnerability Assessment to the US EPA in March 2003 and has implemented various security measures, and continues to enhance security measures, to safeguard against the threat of terrorist attack. Charleston Water System has spent $7.5 million on security improvements and is continually working to improve security. In addition, Charleston Water System receives daily, or more frequent as needed, briefings about water source security from the federal Homeland Security Department.