180 Mio m³ sewage water is treated every year in Munich.
By the way, Munich has two big wastewater treatment plants and over 2.400 kilometer of public sewers with 138 pumps. In total, the sewage water of over 3 million citizens can be treated in those plants in the north of Munich.
Source: https://stadt.muenchen.de/infos/abwasserentsorgung-lhm.html