Automated Hydrant Flushing Devices
DC Water has installed about a dozen automated flushing devices (autoflushers) on hydrants throughout the District.
From March to November, these autoflushers will flush hydrants each day, for 20-30 minutes beginning at 5:00 A.M. DC Water will continue to monitor water quality and may modify the flushing schedule, accordingly.
https://www.dcwater.com/projects/automated-hydrant-flushing-devices