Infiltration through the surface of the permeable pavement (PP) system is essential for obtaining the kind of hydraulic benefits for which PP systems have been designed and planned. Preliminary results from monitoring surface permeability on three streets paved with permeable asphalt over a 30-month period show the need to address the issue of surface clogging in a timely manner through appropriate techniques. Our findings show that the cleaning effect of using a specialized vacuum truck is most pronounced when the Surface Infiltration Rate (SIR) is within the range 50-500 mm/h, where permeability increased from a mean value of 214 mm/h to 5894 mm/h. The threats to high surface permeability are many and may be difficult to prevent. In this study, however, the few areas with a stable high SIR indicate that permeable asphalt not located in heavily trafficked areas and at a safe distance from construction sites and other sedimentation inputs can maintain high surface permeability.