The south Mediterranean area is suffering from lack of drinking water. However, brackish water is abundant in these regions. Desalination of such water can be a solution to provide the needs of the local populations (less than 10 m³/day). Different solutions for brackish water desalination have been developed and many prototypes have been built and tested. Bourouni et al. (1999) developed a water desalination plant based on Aero- Evapo-Condensation Process (AECP). A prototype was built and tested in the region of Kebili in the south of Tunisia. A geothermal brackish water source was used to feed the unit. Promising results were found, since the cost of water was reduced to 1.2 USD per cubic meter of fresh water (Bourouni et al, 1999). The present study shows that the geothermal source can be replaced by solar preheated water.