It has been done before – in fact, there was a mod previously which added water sources, drains, wells and even coloured water. That was back when water was still being initially developed (in fact, the mod started out as a way to simply turn water on, since it was in the code but didn’t appear in the game yet), and I know that the water was simplified before it was released in its current state so I don’t know if all those functions are still available.
[MOD] [SPOILERS] Water Mod v0.7.0 Here’s that previous mod, although it’s obviously not working in the current version of the game it may perhaps provide a starting point for others to carry on 