According to the German Water Resources Law (see quote), sewage is water whose properties have been changed by domestic, commercial, agricultural or other usage, as well as water and precipitations drained from an urban area.[2]


„Assignment of an input or output flow of a process or of a product system to the examined product system and to one or several other product systems.”[2a]


Cultivation of fish, algae, shellfish and other aquatic creatures


Combined cultivation of fish and plants (→ see hydroponics)

Treated water

In accordance with DIN 4046 (see quote): treated water with different subsequent qualities of use from and for domestic, commercial, industrial, and/or agricultural purposes including potentially potable water. For example, if potable water quality is not necessary, treated rainwater or greywater can be used for toilet flushing, cooling, washing, cleaning, or irrigation. [3]


Expansion of a concept or model to further applications. In the case of the concrete ROOF WATER-FARM research project, the word describes parts of the applied research, which simulate the diffusion of the water farm concept throughout exemplary building typologies and areas in Berlin and Germany.


The borders defined by an area of land with a common drainage point. Also called a drainage basin or catchment area.[5]


Is the ecosystem response to the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system.[6]

Building-specific Water Flows

The daily input and output water flows of an individual building include: • potable water (→see potable water) • rainwater (→see  rainwater) • greywater (→see greywater) • blackwater (→see blackwater)


„In accordance with European Standard 12056 – 1: Slightly polluted wastewater that does not contain human feces. A part of domestic wastewater originating from showers, bathtubs, hand basins and / or washing machines but does not include toilet water and highly contaminated kitchen wastewater. [3a]

Greywater Recycling Facilities

Plants that collect minorly soiled water from showers, bathtubs, hand basins and / or washing machines and clean this water to treated water quality. 

Green Infrastructures

Structured elements of garden and landscape architecture—such as vegetated filtration systems, trench-basin systems, or constructed wetlands—that contribute to water resource management, wastewater treatment, aesthetic and leisure functions in public space.


The cultivation of plants (e.g. salad, herbs, strawberries) in a water-based mineral nutrient solution, without soil.

Innovation arena

An arena is a specific setting in which the development and usage of an innovation will be promoted. In the case of cross-sectoral Roof Water-Farm concept at least four innovations areas will be treat: (1) water management, (2) food production, (3) city planning/urban development, (4) architecture/housing industry.

Sewage pipeline

Network of pipes and drains that manage the flows of wastewater to treatment facilities.[9]

Mixed pipeline

Drainage system wherby one pipeline carries wastewater and rainwater.[10]


According to DIN 1989: water from natural precipitation which is not polluted by human use.[3b]

NPK liquid fertilizer

N – nitrogen, P – phosphorus, K – potassium is used as standard fertilizer in agriculture and commercial horticulture to nourish crops.

Life cycle balance

The life cycle assessment as a method to assess environmental terms, which are associated with a product and also product-specific potential environmental impacts. A life cycle assessment study examines the environmental terms and impacts in the course of life’s journey of a product. Thereby it involves production of raw materials, production and transport and also the usage and recycling („from the cradle to the grave“).[11a]

Rainwater Management

central rainwater management Collection of rainwater into a sewer system (whether mixed or separated pipelines). semi -central rainwater management A combination of pipeline collection of rainwater as well as collection basins to support the process of evaporation. decentralised rainwater management Collection of rainwater to be actively rerouted through vegetated evaporative processes.[13]


ROOF WATER-FARM concepts describe building-integrated water treatment systems to irrigate and fertilize roof-top greenhouses. Technologies for water treatment and aquaponics (plant and fish cultivation) demonstrate a hygienically safe usage of rainwater, greywater and blackwater as strategies for city water management and potential urban food production.


Wastewater from toilets that includes human waste.

Separation pipeline

drainage system wherby two conduit pipelines carry wastewater and rainwater separately.[15]

Potable water

Water purified to be for safe human drinking consumption.

Hydrological cycle or water cycle

Recirculation of water above and below the earth, including the atmosphere.[20]

Water Framework Directive

The European Union Water Framework Directive was enacted on 22 December 2000. The aim is to effect a coordinated management and protection policy of watersheds beyond national borders to improve the quality of surface and groundwater throughout the European Union.[22]

Blue Water Footprint

The usage of surface and ground water is referred to as a blue water footprint. Thereby all “consumed” water is that which has been extracted from natural freshwater through evaporation, drainage to the sea, drain to an other watr catchment area or obligation to consumer products.[22a]