CPV code 45262220 designates Water-well drilling in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
45262220 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 45262200 (Foundation work and water-well drilling).