The sewage system is formed by a series of manufactured products such as for example the inspection manholes. The problem concerning the connection between the pipe and the manhole and the tightness of the inspection manhole have often been neglected or underestimated and this caused in some cases subsidence and malfunctions to the collector system. It is therefore necessary to design and carry out inspection manholes equipped with elastic couplings and with a perfect hydraulic tightness. And if there is ground water, it is necessary in relation to a watertight pipeline, to avoid water seepage from the walls of the manholes. Monolite 2000® was born out of these needs: it is a concrete manhole with a circular section especially designed for the completion of a perfectly watertight sewage system both as far as the couplings with the pipe are concerned as for the walls of the manhole. Thanks to the use of joined elements with the tested and safe GLIPP system, we reached the goal both of the purchaser and the project planner.