I've ended up with water in my inventory somehow. I'm in survival mode on my realms server, cheats are not enabled. I was creating a fishing hole when I realized my inventory was full. Upon returning to my base, I found the water. Below are items that may have been involved:
2 Buckets, originally containing water.
Shovel - Efficiency V, Mending I, Unbreaking III, Silk Touch I
Pickaxe - Efficiency IV, Mending I, Unbreaking III, Fortune III
Gravel, Sand, Grass, Dirt, Cobblestone