Water uses an array from the background texture's slots so typically it will work in most tilesets. Yet if you look at the example level of Mystic Isles 2 where the water palette is set to a correct gradient it still looks like crap because 8-bit migrates colors horribly.

It's only something you should put an effort into if it's something you want to be used in a set. Kind of reminds me where I critizised Skulg for not making water work in 8-bit mode in her Where Bad Rabbits Go hell-themed tileset. It's not about being lazy or not giving it a try, it's just about being reasonable and conserve your work time. When giving advice that should always be taken into consideration.