This TIP describes the methods and procedure for the measurement of press fabric permeability to water. The method is suitable for the evaluation of fabrics on the run, without interrupting the operation of the paper machine. This technique could be used to follow changes in fabric permeability, which occurs during fabric life. The method can be used to measure the cross direction (CD) permeability profile and machine direction permeability variation as well as identify localized area of high or low permeability.