International (English)


Sewage water is wastewater and/or stormwater runoff from urban areas. Both can be heavily polluted and must be treated.

The German Federal Water Act (WHG) defines sewage water as follows:
"Wastewater is water that has been altered by domestic, industrial, commercial, agricultural or other uses and dry weather flows (wastewater) and runoff collected from built-up or paved areas (stormwater)."


  • domestic wastewater from toilets, bathrooms, kitchens and washing machines
  • wastewater from business transported to the public sewer system


  • stormwater from uncritical source areas that does not need to be treated
  • stormwater runoffor from problem or critical source areas that contains dissolved dirt particles pollutants and that must be treated

Generally, separate sewage systems should be used to transport wastewater and stormwater and not, as was the case in the past, in a combined sewer system.

Status quo

Germany has achieved a high internationally recognised standard in wastewater disposal. Pollution of water bodies and soil has been considerably reduced and has been going a long way towards more environmental sustainability.

On average, sewer systems in Germany are 41 years old. If a service life of 80 years is assumed, half the time has elapsed. Approximately one fifth of the sewer systems need repairs/redesign in the short or medium term (according to DWA survey). The most commonly encountered damage pattern are broken pipes and defective connections.

More recent sewer systems – in particular those made of plastic – have probably not yet been inspected and analysed. They will most likely improve the status quo of the total network due to significantly less damage. According to the DWA, their number is constantly increasing.

Requirements and goals

  • high-quality, reliable sewer systems that satisfy long-term operating requirements
  • permanently leak tight and corrosion-resistant sewer systems to prevent environmental damage
  • maintaining and ensuring the technical infrastructure and preserving the value of a national wealth grown over generations