Abstract: A spirit level assembly attachable to a free end of a pipe section being installed includes a housing block of generally rectangular cross-section in which a series of viewing ports are formed through opposed side walls thereof. Fitted into each of the viewing ports is a spirit level vial or bubble. Integrally formed on the opposed ends of the housing block are cylindrical stubs of predetermined diameter corresponding to commonly encountered pipe sizes. The stubs are threaded in accordance with the National Pipe Thread convention. When the housing is screwed onto the length of pipe being leveled or plumbed, an appropriate bubble vial can be viewed to establish the desired horizontal or vertical orientation of that pipe segment.