Abstract The water management is critical to achieve the full potential of PEMFC (polymer electrolyte membrane fuel cells). The surface contact angle and roughness properties of bipolar plate are the main factors affecting water management in a fuel cell and PEMFC performance. The effects of the contact angle and roughness of polymer composite bipolar plate and hydrogen flow rate on power density of PEMFC are analyzed by RSM (response surface methodology) in this study. Fuel cell performance tests are carried out at different hydrogen flow rates by using composite bipolar plates having different values of contact angle and roughness. We observed that the power density of the fuel cell increases with the increase in the hydrogen flow rate due to the increase in hydrogen transport on the anode surface both with respect to contact angle and roughness. At the constant hydrogen flow rate, the power density shows a maximum with the increase in both contact angle and Ra (surface roughness). The optimum values of the contact angle and hydrogen flow rate for the studied range are 81.2° and 1.87 dm 3 min −1 , respectively. In addition, the maximum fuel cell performance is obtained at roughness of 1.69 μm and hydrogen flow rate of 1.97 dm 3 min −1 .