This report provides an update to the Water Critical Infrastructure and Key Resources (CIKR) Sector-Specific Plan (SSP), as input to the National Infrastructure Protection Plan (NIPP). This update, based on guidance issued by the U.S. Department of Homeland Security (DHS), provides a summary of advances in the processes set out in the SSP and the achievement of milestones. It is intended to inform Water Sector partners, stakeholders, and Federal, State, local governments, tribes, and other interested parties about updates to key CIKR protection efforts in the Water Sector. The U.S. Environmental Protection Agency (EPA) prepared this update in collaboration with the Water Sector Coordinating Council (WSCC) and the Government Coordinating Council (GCC), two critical vehicles that were established under the NIPP to provide a focal point of interaction respectively with the water industry and other Federal and State partners. The Water SSP provides an overview of the Water Sector and describes the vision statement and four goals for the Sector (see Table 1). In addition, it describes the protective programs, measures, and research and development ongoing in the sector. Since the Water SSP was published in May 2007, the Water Sector has continued to enhance CIKR protection from all hazards. This SSP update addresses several of the key activities that have been underway since that time, and is organized to be used as a cross reference to the SSP (see Table 2). As shown in Table 2, SSP Sections 5 and 6 are being updated. This update is not intended to address every change within the Water Sector since May 2007, but rather to highlight key efforts. In accordance with the NIPP, the Water Sector will evaluate the status of the SSP on an annual basis.