There are more than 5,000 Combined Sewer Overflow (CSO) networks in the local province that need a technical upgrade. The direct effects of a wide application of NBSWT on the water quality of the receiving water bodies can be estimated, and reduction in the local indexes of flooding risk can be modelled with good approximation. The design of the MULTISOURCE ENTS pilot in Italy reduces the area required for treatment and therefore increases the potential of replication for such configuration even in difficult urban scenarios with low availability of usable land.