This document deals with principles of the investigation of soil, rock and groundwater as subsoil and construction materials as part of the geotechnical investigation services in accordance with prEN 1997. It defines concepts and specifies requirements relating to sampling by drilling and excavation and groundwater measurements. The aims of such ground investigations are: a) to recover soil and rock samples of a quality sufficient to assess the general suitability of a site for geotechnical engineering purposes and to determine the required soil and rock characteristics in the laboratory b) to obtain information on the sequence, thickness and orientation of strata and joint system and faults; c) to establish the type, composition and condition of strata; d) to obtain information on groundwater conditions and recover water samples for assessment of the interaction of groundwater, soil, rock and construction material. The quality of a sample is influenced by the geological and hydro-geological conditions, sampling method, the personnel taking the sample and by the sampling equipment. Soil sampling for the purposes of agricultural and environmental soil investigation is not covered. NOTE Soil sampling for these purposes is to be found in ISO 10381 series. Water sampling for the purposes of quality control, quality characterisation, and identification of sources of pollution of water, including bottom deposits and sludges is not covered. NOTE Water sampling for these purposes is to be found in ISO 5667 series.