House owners must prove that sewer lines (downpipes and house connection lines up to DN200) meet current environmental protection requirements. 

In this regard, there are three requirements that must be met by sewer lines. The pipes must be leak-proof, stable, and operationally reliable. In principle, therefore, it makes sense to identify the condition of the pipelines by means of an inspection. Based on this, rehabilitation work can be carried out as required - provided that trenchless rehabilitation of the pipelines is still technically possible.