The UMG Hospital is one of Germany’s leading clinics. In view of the construction of a new surgical pavilion a new 1,2 km long gravity sewer has been built in order to drain storm. The entire sewer was installed in an urban area by microtunnelling at a depth of more than 10 meters. The sewer consisted in three different sections having an internal diameter of 1.400 mm, 1.600 mm and 2.000 mm) I.CO.P. also built three shafts by means of secant piles in order to link the different sections.