This paper discusses the most important policies and regulations supporting the decentralized management, harvesting and utilization of rainwater in Germany, where such measures have been increasingly applied during the last few decades. The development and implementation of specific policies and regulations contributed significantly to that trend. They also work as incentives for the development of advanced technologies and businesses as well as the widespread and growing implementation of measures for decentralized rainwater management, harvesting and utilization by public and private actors. This development can generally be associated with environmental and economic concerns related with required adaptation to changes in climate, demographic structures and infrastructures as well as climate resilience including flood control and drought resistance. The addressed and supported measures can be assigned to the two focus areas 'Decentralized rainwater harvesting and utilization', aiming for saving of precious fresh water resources and centrally supplied drinking water, as well as 'decentralized rainwater retention and management', aiming for flood control and protection of existing infrastructures and ecosystems. The decentralized management of rainwater and its separation from combined sewer systems at the source is generally regarded as the state of the art and basic condition for sustainable municipal wastewater management.