This specification covers the basic requirements for equipment to be used for the collection of uncontaminated and representative samples from single-phase geothermal liquid or steam. Sample probes shall be used to extract liquid or steam from the main part of the geothermal flow rather than using a wall-accessing valve and pipe arrangement. Sampling lines shall be as short as practical and of sufficient strength to prevent structural failure. Valves which control access to the sampling point shall have straight throats. The tube through which the sample flows shall be continuous through the cooling location so there will be no possibility of sample contamination or dilution from the cooling water. Liquid sample containers and compatible closures shall not bias the sample components of interest. Devices used to collect and transport the gas component of the samples shall be resistant to chemical reactions and to gaseous diffusion or adsorption. Filters, when used, shall be housed in a pressure-tight container assuring that the full flow passes through the filter. The sampling apparatus shall be kept clean.