Geotextiles are products of uttermost importance for filter and drainage layer construction in landfills barriers systems, they allow to control leachate levels inside dumping cells. The most relevant hydraulic properties considered in the design of these layers are aperture opening size, hydraulic conductivity and hydraulic transmissivity, which can be affected by biological clogging during landfill operation since these layers are in constant contact with fluids that possess high biological activity, like leachate. In this research, the effect of biological clogging on woven and non-woven geotextiles was investigated by immersing geotextiles samples in three different fluids (deionized water, natural leachate and nutrient solution) and determining the change in their hydraulic conductivity after different times of immersion. General trends observed show that hydraulic conductivity decreases with time for specimens immersed in natural leachate and nutrient solution. Finally, the effects of changes in the hydraulic gradient were explored in order to allow an increase in flow rate that might help to remove biofilm from geotextile fibers.