I have stayed at Tradewinds (Paradise Village) twice and took my Britta water filer from home. I filtered tap water and kept it in the refrigerator. Also made ice cubes and coffee with no problemo!
Why wouldn't restaurants sell you bottled water instead of giving you free tap water? Who can begrudge them making a buck? We American's can really be cheapskates.
All the dive boats I have been on supply lots of bags of bottled water free and urge everyone to drink up - hydrate!