In-situ Flush Apparatus for Water or Waste Water Filters

A flush apparatus for a filter underdrain system can include a fluid connection member having a body with a first end and a second end, the first end adapted to connect to a fluid source; a top plate connected to the second end of the fluid connection member; and a bottom plate opposing the top plate and adapted to engage a top portion of an underdrain system, the bottom plate having orifices that distribute fluid to the underdrain system to transport materials through the underdrain system. A system for cleaning unwanted materials from a water or waste water treatment filter and a method of transporting unwanted materials through an underdrain system are also disclosed.