What counts as water when casting the spell control water? I'm sure that the answer could be "that's up to the DM", but how does the DM justify this judgement? There's many ways to approach this question; here are a few examples:
- Chemically: in that anything that mostly composed of H20 counts as water. Muddy river, glacial ice, frozen lake, mist, fog, etc.
- Intuitively: in that anything that seems like water counts as water. It's liquid, mostly clear, you can swim in it and drink it, etc.
- Simplistic: where only liquid, mostly pure water counts as water.
Related question: What the heck is "freestanding water"?
Spell information: https://www.dndbeyond.com/spells/control-water