Whether french fries or luxury menus, all food that is consumed will sooner or later find its way into the sewers. These usually run smoothely in Germany and therefore rarely move into our consciousness. Each person uses an average of 107 liters of water per day - for drinking, washing, showering, cleaning, doing the dishes or just for flushing the toilet. So drinking water, our most important resource, turns into waste water. This waste water flows through our house pipes and into an underground sewer system, which is over 5500 km long in Hamburg alone and constantly needs cleaning and maintenance.