U.S. Air Force Airman Alex McClendon, 633rd Aerospace Medicine Squadron bioenvironmental engineering technician, samples tap water in the education center at Langley Air Force Base, Va., June 12, 2015. After sampling the water, McClendon checks water to ensure it meets the drinkable standard of between 7.2 and 8 on the pH scale and less than one percent of the water is chlorinated. (U.S. Air Force photo by Airman 1st Class Devin S. Michaels/Released)

U.S. Air Force Airman Alex McClendon, 633rd Aerospace Medicine Squadron bioenvironmental engineering technician, walks toward the education center at Langley Air Force Base, Va., June 12, 2015. The education center and other buildings on base get their tap water checked monthly for continued compliance with Air Force Instruction for drinkable water. (U.S. Air Force photo by Airman 1st Class Devin S. Michaels/Released)

U.S. Air Force Airman Alex McClendon, 633rd Aerospace Medicine Squadron bioenvironmental engineering technician, adds a de-chlorinating solution to a tap water sample at Langley Air Force Base, Va., June 12, 2015. If the water fails to meet the Air Force’s health standards, base civil engineers will flush the system, locate the problem. (U.S. Air Force photo by Airman 1st Class Devin S. Michaels/Released)

U.S. Air Force Airman Alex McClendon, 633rd Aerospace Medicine Squadron bioenvironmental engineering technician, adds a pH-testing solution to a tap water sample at Langley Air Force Base, Va., June 12, 2015. Bioenvironmental Airmen from the 633rd AMDS bring no less than 10 samples to the laboratory monthly, as to ensure the water is free from coliform bacteria. (U.S. Air Force photo by Airman 1st Class Devin S. Michaels/Released)