As the Maldives are Muslim, alcohol is banned for the local population. However, nearly all resorts and liveaboard boats are licensed to serve it, usually with a steep markup. Expatriate residents have an allowance that they can use in Male.
Maldivians generally do not drink alcohol although this is less true of the younger generation. They are, however, unhappy about being filmed or photographed while drinking.
Tap water in resorts may or may not be drinkable -- check with management. Bottled water is extortionately priced, with US$5/bottle being typical.