This study investigated the performance of a Double Pass Solar Water Heater (DPSWH) with reflector. The influence of the mass flow rate on the outlet temperature, thermal performance, and overall performance had also been analyzed. The data were taken at different mass flow rate of 0.0022 kg/s, 0.0028 kg/s, 0.0033 kg/s, 0.0039 kg/s and 0.0044 kg/s from 9:00 a.m. to 4:00 p.m. at an interval of 30 min in the month of November 2017. Results showed that, the efficiency increased with the increasing mass flow rate whereas the temperature difference decreased with the increasing mass flow rate. The maximum efficiency obtained for a higher mass flow rate of 0.0044 kg/s was 50.26%. The maximum efficiency for other mass flow rates was 47.61%, 47.98%, 48.82%, and 48.89%, respectively. All these efficiencies were found in the middle of the day around 12:00 p.m.-1:00 p.m. as the solar radiation was maximum in that period. Moreover, the performance of double pass solar water heater had been compared with the single-pass solar water heater and result showed that the double pass solar water heater had better efficiency over the single pass solar water heater. (C) 2019 Elsevier Ltd. All rights reserved.