Waterman telescoping valves are designed to control the height of liquid within a pond, reservoir, or other holding chamber. In modern sewage treatment facilities, one specific use is to control the level of effluent in settling basins. Also called Decanting Valves or Sludge Draw-off Valves, the assembly consists of a drain tube which can slip up and down inside a stationary vertical pipe. Through a lifting device, the tube is raised and lowered to maintain the desired level within the chamber. Waterman manufactures telescoping valves in a range of sizes from 4″ tube diameter to 36″ tube diameter. V notches or flared tube tops can be provided when requested. Also nonrising stem tube design is available.