What is the legal nature of a stabilisation basin created merely by excavation of structurally unmodified ground? Should such a basin be considered to be land or can such a basin form part of a structure, namely part of a sewerage system as a utility network (linear structure) within the meaning of Section 509 of the Civil Code (under which a structure is deemed to be a legally separate immovable thing distinct from the land itself)? What is the legal significance of the fact that the land (the stabilisation basin) is used together with a linear structure (sewerage system) for the purpose for which the structure serves? Can a stabilisation basin form part of a linear structure? These questions were addressed by the Supreme Court of the Czech Republic in its judgment case No. 22 Cdo 2675/2025, dated 16 December 2025.
According to the legal opinion of the Supreme Court, a stabilisation basin created solely by excavation of structurally unmodified ground, where water retention is ensured by the natural subsoil and which lacks a material substance distinct from the surrounding land (i.e. it lacks the structural integrity of construction material), does not constitute a structure in the civil law sense, but rather forms part of the land. Such a basin cannot become part of a sewerage system as a utility network (linear structure) within the meaning of Section 509 of the Civil Code, since land cannot form part of a structure.
This conclusion is not affected by the fact that the stabilisation basin is necessary for wastewater treatment, as the mere circumstance that land (the stabilisation basin) is used together with a linear structure for the purpose for which the structure serves does not in itself mean that it may (or must) form part of that structure.