Tech. Sgt. Marcus Poulos, 36th Medical Operations Squadron Bioenvironmental Engineering Flight environmental non-commissioned officer in charge, and Tech. Sgt. Richelle Rodriguez, 36th MDOS ambulance services NCOIC, test the pH level of a water sample taken from a potable water transport truck Aug. 22, 2013, on Andersen Air Force Base, Guam. Eight randomly selected drinking water outlets on base are tested by the bioenvironmental Airmen at least once per month. (U.S. Air Force photo by Staff Sgt. Melissa B. White/Released)