Lack of fresh drinking water in isolated communities is one of the common problems around the world. The availability of pure drinking water is only 0.5% of total freshwater demand. The fresh drinking water situation in Bangladesh is alarming especially in isolated regions. Most of the isolated and rural regions are using underground water for drinking and cooking. However, the majority of the underground water TDS level is as high as 2000-7000 mg/l, which is really harmful to human health as allowable limit is 1000 mg/l. To address this issue, a small pure drinking water system is proposed that uses available solar energy. The system is designed with reverse osmosis process for rural or isolated communities to facility he pure drinking water demand in the regions. The renowned island Sandwip has been chosen to implement the system as it is one the isolated region's in Bangladesh. It was that the water purification cost of the scheme becomes as low as 0.002/litre, which is cost-effective than present existing pure drinking water system in Bangladesh. The cost of electricity found to be as low as 0.13/kWh for evening lighting.