This International Standard specifies a test method, which covers the determination of the hydraulic conductivity by a constant-head method for the laminar flow of water through granular soils (sand and gravel). The procedure is to establish representative values of the hydraulic conductivity of granular soils that may occur in natural deposits as placed in embarkments, or when used as base courses under pavements. In order to limit consolidation influences during testing, this procedure is limited to disturbed granular soils containing not more than 10% soil passing the 75- um sieve.