NWTC is the first Training Center authorized in France to provide training for the Proficiency Certificate for Working in Confined Spaces (CATEC®), which aims to prevent the risk of accidents, albeit infrequent but often severe because lethal, facing staff working in some drinking water supply or sanitation facilities, such as sewers, pumping stations or water tanks. The concepts always developed by NWTC, i.e. practical training, delivered on secure facilities, models of real structures, are indeed included in the frame of references. For CATEC®, NWTC has developed sanitation structures that can be visited constituting a unique tool in France, including its associated educational units. The most spectacular facility is an underground network of 100 m long, supplied with water and very realistic. It allows the participants to work safely in conditions very similar to real ones. It also allows the simulation of alerts and accidents for comprehensive training of the trainees.