* Water doesn't form piles. Water is a liquid and takes the shape of its container.
* "Fetch" implies bringing something. You can't "fetch" something that doesn't have a defined shape or form.
Here are some better ways to phrase the request:
* "Bring me a pitcher of water."
* "Get me a glass of water."
* "Fill a bucket with water for me."
* "Could you please get me some water?"