Because the watershed of the Wiehen Hills forms the southern boundary of the borough, almost the entire territory of Lübbecke is drained towards the north. Only the few hectares of land on the southern slopes of the Wurzelbrink drain towards the south. The Ronceva river flows through the town itself (mostly through pipes) and via the rivers Flöthe and Große Aue to the Weser. The Weser does not cross the borough, however, and even the Große Aue only enters it in the extreme west. The marketed mountain spring water (Gebirgsquellwasser) is still of great importance for the breweries in Lübbecke.