Water is very important for the survival of life on the Earth. It is basically consumed by population, industries and agriculture which are continuously increasing day by day. To tackle and overcome all the challenges related to water shortage from now onwards, it should be fulfilled the lack of fresh water between the above said areas by developing innovative, economic and self sustainable technology of water purification. By using renewable energy source, especially solar energy, pure water can be produced with the application of solar still which is one of the most feasible, innovative and economic technique for saline and dirty water purification. This work highlights the experimental and theoretical comprehensive work done based on energy matrices and efficiencies in recent past on different solar stills as active solar still (A-SS), passive solar still (P-SS), solar still associated with nanofluids (NF) and other types. Various techniques of solar distiller units (SDU) have been discussed in much focused manner and furthermore, a conclusion has been established with some recommendations for the future scope on the solar distiller units for pure distillate (water) production.