to support a community in arid of desert conditions,potable, i.e. fit to drink, water must be supplied for domestic use, and other water for crops an general purposes.many desert regions (e.g.central australia) have regions of salt or brackish water underground, and it is usually much cheaper to purify this water than to transport fresh water form afar. since deserts usually have larg in solationm, it ts reasonable to use solar energy to perform this purification by distillation.