Application of solar energy to purify the water is advancing rapidly since it is an attractive alternative because of its simple technology; non-requirement of skilled labor for maintenance work, low energy consumption and no fuel is required for operating such water purification unit. This paper deals with the performance evaluation of the solar water purification at Mechanical Engineering Department MMMUT Gorakhpur, India. To perform this experiment, parabolic trough of fixed rim angle and length is considered. Based upon rim angle and length other pertinent parameters are calculated and selection of materials for fabrication of the unit is done. After that solar water purifier unit is fabricated. The solar parabolic collector utilizes the concentrating solar power technology to concentrate the solar insolation. The performance of parabolic trough is evaluated by considering the effect of glass cover on the concentrator. Various results are plotted between the temperature of the fluid and time keeping other parameters held fixed. Further a comparative study is performed for solar water purification unit with and without glass cover. The purity of water is measured based on its pH value and total dissolved solid (TDS).