Staff Sgt. David Overstreet, 28th Civil Engineer Squadron water fuels systems maintenance, ensures proper valve position on a high expansion foam system at the Petroleum Oil Liquids Control Facility on Ellsworth Air Force Base, S.D., Dec. 19, 2012. Working in water fuels systems maintenance, Overstreet installs, inspects, repairs, and manages the many water systems on base, including plumbing, water distribution, wastewater collection, and fire suppression systems. (U.S. Air Force photo by Airman 1st Class Anania Tekurio/Released)