This case study is about a full-scale residential settlement project in an urban area in Hamburg, Germany. The settlement was built between 1982 and 1994 and consists of 36 single-family houses with approx. 140 inhabitants. The project aims at having an ecological closed-loop process via on-site wastewater treatment and therefore independence from a sewage system. Rainwater harvesting, composting toilets and constructed wetlands were the technologies applied in the project. Thereby a high resource and energy efficiency can be achieved.