Tech. Sgt. Roshia Johari, the 554th RED HORSE NCO in charge of water and fuels systems maintenance contingency training, uses an ultrameter to test the quality of a water source June 9, 2015, at Andersen Air Force Base, Guam. The Reverse Osmosis Water Purification Unit’s purification process starts with finding a viable water source, which could be fresh, brackish or saltwater. (U.S. Air Force photo/Airman 1st Class Joshua Smoot)