Abstract: The legal regulation of drinking water supply and sewage treatment belongs to the core field of municipal water management and is an important part of water management. "Human rights to water" with permanent protection of drinking water supply as the core content has become the focus of discussion, especially at the international and EU level. The article begins with an overview of the development of water management laws in Germany, which ensures an order of supervision in public law. Despite the change of Water Law to water environmental quality compliance being influenced by the EU Water Framework Directive, the drinking water supply and sewage treatment is still one of the core contents in Germany. At the EU level, the Municipal Sewage Directive and the Drinking Water Directive provide specifications for these two areas, in addition to the Water Framework Directive. At the German level, first of all, the organization of water supply and sewage treatment is assessed from the centralized and decentralized development trend and the privatization trend for the guarantee of efficiency. Secondly, the development of German Water Law and the licensing system as the core of water regulation under the reform of federalism are introduced. Then, in the field of sewage supervision, the best available technology of sewage discharge permits, direct and indirect discharges, sewage charges and sludge treatment are analyzed respectively. At last, two aspects of water source protection and drinking water supply are introduced in drinking water supply areas, and the challenges of the field of water regulation in Germany pointed out.