@pleiades you may want to consider the largest/oldst body of water ever found.
Researchers found a lake of water so large that it could provide each person on Earth an entire planet’s worth of water-20,000 times over. Yes, so much water out there in space that it could supply each one of us all the water on Earth-Niagara Falls, the Pacific Ocean, the polar ice caps, the puddle in the bottom of the canoe you forgot to flip over-20,000 times over.
Not sure about a single planet of water but it looks like there’s lots of water out there in general and some of it massively grouped together. I found this pretty mind blowing