Abstract: The height adjustable standpipe includes multiple, cylindrical, coaxial drain sections of gradually diminishing cross section. The sections preferably alternate between brass and PVC plastic, and have grooves adjacent the ends of the PVC sections for retaining O-rings that serve as gaskets between the two adjacent sections. Thus, for example, a PVC section would preferably have one or two peripheral grooves on the outer surface near the end that passes inside of the next adjacent brass section, and the same PVC section would have one or two peripheral grooves on the inner surface near the opposite end, through which passes another brass section. Each of these peripheral grooves includes a rubber O-ring seated therein and projecting therefrom to form a water-tight seal with the adjacent surface of the brass section engaged by that end of the PVC section. A travel stop mechanism is employed to limit the travel of the sections of the adjustable standpipe with respect to one another.