This European Standard specifies the relevant characteristics of geotextiles and geotextile-related products used in the construction of reservoirs and dams, and the appropriate test methods to determine these characteristics. The intended use of these geotextiles or geotextile-related products is to fulfil one or more of the following functions: filtration, separation, reinforcement and protection. The separation function will always occur in conjunction with filtration or reinforcement, and hence will not be specified alone. This European Standard is not applicable to geosynthetic barriers, as defined in EN ISO 10318 1. This European Standard provides for the assessment and verification of constancy of performance of the product to this European Standard and for factory production control procedures. Particular application cases may contain requirements regarding additional properties and preferably standardized test methods, if they are technically relevant. This European Standard may be used to derive design values by taking into account factors within the context of the definitions given in EN 1997 1 (Eurocode 7), e.g. factors of safety. The design life of the product should be determined, since its function may be temporary, as a construction expediency, or permanent, for the lifetime of the structure.