Internal surfaces of polymeric (PVC, PE, PP, and PB) pipes were assessed for potential colonization by microorganisms present in a water distribution system. Biofilms that had formed on the surfaces of particular polymer samples were examined by SEM microscopy and Koch's method. Surface damage caused by microbial activity was measured by contact profilometry. PP (1.5×10⁶ CFU/cm²) and PB (4.9×10⁵ CFU/cm²) showed very high potential for developing biofilms on their surfaces. They also displayed considerable surface damage as substantiated by the decrease in the coefficient of profile asymmetry, which amounted to 50% and 85% for PP and PB, respectively.