The Varaždin agglomeration project involves the construction of a public drainage system of a total length of 241.487 km, 108 pump cells, 3 umbrella retention basins, and the rescue of 2.654 km of existing gravity pipelines. Also, the retrofitting of the existing UPOV with a purification step III, and a capacity to ensure capacity of 127.000 ES, will treat the wastewater of the public sewerage system and effluent from septic tanks from septic tanks where construction of the drainage system is not profitable, allows for an additional connection of 40.468 inhabitants to the waste water drainage system.