Cologne, 06. August 2025 - With its position paper on climate-resilient water management, which discusses the potential for sustainable use of water reuse applications in the building sector, figawa e.V. and its technical experts are contributing to the discourse among experts.
Regulation (EU) 2020/741 of the European Parliament and of the Council of 25 May 2020 on minimum requirements for water reuse entered into force on 26 June 2020 and has been applicable in the Member States of the European Union since 26 June 2023, making it legally binding in Germany for the first time. The Regulation sets the minimum framework for the reuse of wastewater for agricultural irrigation and urban purposes. With the national adaptations of the legal framework, water reuse for these purposes will become possible in Germany. For the targeted implementation and to ensure the low-risk and technically sound realisation of such projects, the DWA-M-1200 series of technical guidelines provides technical guidance for the reuse of treated water from municipal sewage treatment plants with a predominant proportion of domestic wastewater for agricultural, horticultural and urban uses.
There is further potential for the reuse of water from various sources in the industrial and building sectors, for example, through the use of treated water for the irrigation of agricultural land and horticultural crops, as well as for the irrigation of parks, roadside greenery, and green spaces and sports facilities. The introduction and expansion of water reuse and possible areas of application require clear and unambiguous legal requirements regarding the water qualities that can be used, which are implemented, for example, in the form of application-specific water quality requirements.
Alternative water sources offer significant potential for more sustainable and cost-efficient water management. By taking a differentiated view of water requirements and making targeted use of non-potable water, considerable resources and costs can be saved in suitable areas of application. However, further factors must be taken into account for the practical implementation of such concepts, such as hygienic safety and human health, the necessary infrastructure for separate water supply, legal framework conditions, and consumer acceptance.
A wide range of options are available for this purpose, which can be used depending on the area of application and local conditions. Rainwater collected from roof surfaces or other suitable surfaces offers a wide range of possible uses. Greywater, a partial stream of domestic wastewater without partial streams from toilets and urinals, sometimes differentiated into heavily and lightly contaminated, as a resource for water and energy reuse, for example from sinks, showers or washing machines, can also be reused after appropriate treatment. Surface water from rivers, lakes or artificial ponds is another option, provided it is of the required quality for the respective application.
Process water plays an important role in industrial and commercial contexts. This water, which does not need to be of drinking water quality, can be treated and reused for specific processes. Treated municipal wastewater, which has been purified in sewage treatment plants, can also be used for certain purposes such as irrigation or industrial processes. In industry, process water is also produced which, provided it is not heavily contaminated, can be recycled after appropriate treatment.
Depending on the area of application and the required water quality, these diverse alternative water sources offer a useful supplement to conventional drinking water use and contribute significantly to the conservation of valuable drinking water resources. However, it should be noted that the use of such alternative sources often requires specific treatment and must always comply with the applicable requirements and quality standards. The integration of these alternative water sources into existing systems is therefore an important task for future water management and requires innovative solutions as well as careful planning and implementation.
With this position paper and the demands, it contains, figawa e.V. intends to continue the discourse on further possible applications of water reuse with authorities, research institutions, stakeholders and others in order to jointly provide the technical basis and practical experience for evaluating these applications and to achieve integration into the necessary legal framework in the foreseeable future.
The position paper ‘Climate-resilient water management – focus on the district & building sector’ is available for free download at www.figawa.org/en/topics/water-reuse.
