7th CES activates fire-hydrant flushing Published Oct. 25, 2012 7th Civil Engineer Squadron DYESS AIR FORCE BASE, Texas -- The 7th Civil Engineer Squadron has begun flushing fire hydrants around base and will begin renovating the water system Oct. 29. The flushing will continue for approximately 45 to 60 days. For more information, call 2nd Lt. Sarah Dunlap at (325) 696-2602.