AbstractThis article presents the results from a study on the cross‐plane water flow through the needle punched nonwoven geotextiles produced from polypropylene fibers. Different types of nonwoven geotextiles are produced by varying the processing parameters during the needle punching process. The pore characteristics and the cross‐plane water flow (or permeability) through the nonwoven geotextiles are measured by liquid extrusion porometry and water permeability tester, respectively. The water flow velocities through the geotextiles are predicted by the finite element analysis. There is a good correlation between the average velocity data obtained from water permeability test and theoretical prediction based on finite element analysis. The pore characteristics play an important role in water permeability behavior of nonwoven geotextiles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008