The water supply system remains largely unprotected from terrorist threat. This volume provides a unique quantitative risk assessment methodology for protection against terrorist contamination, vandalism, and other threats to water supply systems. It includes processes for security and safe facility operations; an integrated model to the risk assessment of surface water, dams, wells, wastewater treatment facilities, reservoirs, and aqueducts of large urban regions; and a discussion on intelligence analysis incorporating risk assessment for terrorism prevention. It also discusses legal and regulatory requirements related to the groundwater and water supply protection policy against terrorism.