The paper describes a series of laboratory tests that were carried out to quantify the saturated-unsaturated hydraulic properties of woven and nonwoven geotextiles in virgin condition and contaminated with kaolin fines. The test program included 1-D column tests of a single geotextile layer in sand subjected to surface water infiltration loading. The column tests showed detectable changes in rate of wetting front advancement in the vicinity of the geotextile layer consistent with a capillary break mechanism. Transient ponding of water above the geotextile was observed to vary with the initial unsaturated hydraulic conductivity of the geotextile. A numerical code was developed to simulate the 1-D column tests and numerical results are shown to be in good agreement with physical test results. The work reported here leads to the recommendation that the ratio of geotextile to sand saturated hydraulic conductivity may have to be greater than one to prevent lateral flow of water above a geotextile in sand fills used in wall, embankment and road applications.