The Mangfalltal valley has supplied Munich with most of its drinking water since 1883. All supply pipes that are older than 120 years have to be replaced. The actual water pipeline is a steel pipe which will be installed after the pipe has been built.
The project is divided up into several phases. During this phase the Mangfall tunnel was constructed from 1993 to 1995 and the Mühlthal tunnel in 1995.