This standard covers the semantics (meaning) of data exchanged between data producers, users and databanks, independently from the software device and the formats used to exchange the files. It provides a consistent set of terms defining selected objects and their related attributes. The standard is not applicable to: ? data describing domestic uses (drinking water, waste water) or qualitative aspects ; ? real time data or data calculated from models; ? all the various characteristics on the organizations exchanging data concerned; ? debimetric measures.