Drainage systems in industrial and commercial areas generally have to meet increased requirements in terms of leak tightness, chemical resistance and temperature resistance. The ingredients of the wastewater are not always clearly definable. This applies to small quantities of undefined wastewater from laboratories or similar facilities as well as to discharges from large process plants.

Rainwater can also be highly contaminated due to pollution of filling and storage areas.

Drainage systems to this extent fall under Section 62 para. 1 sentences 1 and 2 WHG and must be such that an adverse change in the properties of water bodies is not to be feared.

This principle of concern, which is also formulated in § 32 and § 48 WHG, places strict requirements on the operator and all other persons working at the plant. The aim is not only to avert specific threats to water bodies, but to achieve such a level of safety that adverse alteration of water bodies is unlikely based on human experience. Accordingly, all plant components such as pipes, manholes, inlets and tanks must meet the chemical, thermal and static requirements.