On creative players are not allowed to use water on their plots. I've always wanted to make that sandy beach RP that everyone could enjoy! There is really no reason to make water unusable on creative
It's disabled because of lag. Sorry, if you want to make water you can always use glass to make something that resembles water. No Support.
There is actually a reason to make water and lava unusable, they were used for griefing. Imagine if you spent a week working on a project and then someone came alone and put water all over it. Do you have any idea how much of a pain it is to clean up? It's simple they just removed it :P
There is a reason for it being removed. Lag. Same goes for lava. I just use ice instead of water, then get someone who is good with world edit to replace the ice with water.
Get some ice. Place it in the areas you want the water in. Get into survival mode with a diamond pickaxe with efficiency. Mine the ice. Boom,water. It isn't rocket science. Neutral.