Water Security Act of 2007

Water Security Act of 2007 - Authorizes the Administrator of the Environmental Protection Agency (EPA) to provide grants for: (1) vulnerability assessments of publicly owned treatment works or community water systems; (2) implementation of security enhancements; (3) the development, expansion, or upgrading of emergency response and site security plans; and (4) the voluntary creation of mutual aid and emergency network preparedness agreements.

Authorizes grants for security enhancements of treatment works and community water systems that meet specified certification requirements. Prescribes disclosure limits and protections for vulnerability assessments. Limits the federal cost share of an activity funded under this Act to 50%.

Authorizes the Administrator to: (1) provide technical guidance to small publicly owned treatment works and small community water systems (serving fewer than 10,000 individuals) for conducting vulnerability assessments, emergency response plans, or site security plans and for implementing security enhancements; and (2) make grants to qualifying nonprofit organizations to improve assessment methodologies and tools and to implement a comprehensive training program.

Requires the Administrator to research and review: (1) means of providing alternative processes to convey, treat, and dispose of wastewater and to treat and deliver drinking water if a disruption of service event occurs; (2) means by which a distribution system of a community water system could be compromised to allow the delivery of any hazardous chemical or substance; (3) methods for monitoring a collection system for hazardous substances and unauthorized entry; and (4) strategies for recovery from, and restoration of services after, such an event.