In Europe and Germany, the proper handling of water is regulated by standards and guidelines. Below is a summary of the most important standards and guidelines:
EU regulatory framework
With the EU Water Framework Directive, the EU member states have created common ground in comprehensive water protection. This also considers water collection areas that cross state lines. The general aim is to achieve and maintain a "good water status" for all surface water bodies and groundwater bodies by 2015. The member states independently have implemented their respectively defined objectives of the water framework directive in their regulations.
Implementation in Germany
The German Federal Water Act (Wasserhaushaltsgesetz, WHG) was adapted and brought into effect in March 2010 as amended. In the case of resettlement, the accumulating stormwater must be returned to the local natural water cycle. In addition, the best available technologies must be used for technical solutions in accordance with the cost-benefit ratio.
Based on the Federal Water Act, also individual state laws implemented the guidelines of the EU Water Framework Directive.
Planning guidelines in Germany
DWA A 138 worksheet
General directive for "Planning, Construction and Operation of Facilities for the Percolation of Precipitation Water" („Planung, Bau und Betrieb von Anlagen zur Versickerung von Niederschlagswasser") . The directive describes all kinds of occurring stormwater and all possibilities for a professional infiltration with respect to the respective pollution potentials. The goal is to achieve sustainable stormwater management by taking soil and water protection considerations into account.
DWA M 153 bulletin
Provides "Recommendations for handling stormwater" („Handlungsempfehlungen zum Umgang mit Regenwasser"). The bulletin recommends types of pre-treatment before stormwater infiltration or discharge into a water body.
DWA A 117 worksheet
For "Dimensioning Stormwater Holding Facilities" („Bemessung von Regenrückhalteräumen") .
DIN 1989 part 1-3
Regulation of requirements for rainwater harvesting systems.
Country-specific regulations on the handling of stormwater must be complied with in general.