Minecraft wiki entry for Water, associated text: The texture subtly overlaid on the screen when underwater is that of the original water texture from 0.0.12a. It is one of the oldest textures still currently in the game, arguably tied with the bedrock texture on end crystals.
The outdatedness of this texture is not considered a bug or oversight, unlike many other outdated textures.[16]
This texture is particularly difficult to notice due to its extreme transparency,[17] as well as the fact that other blocks will likely make the scene noisy enough to further obscure it under most conditions.
While underwater, the player's FOV (field of vision) is lowered by 10 to simulate light refraction. This can be disabled via FOV Effects.
Water does not prevent explosions from activating. This effect is due to water's high blast resistance, causing it to absorb any normal blasts, with the exception of explosions from underwater TNT.
If a player with the levitation effect touches water, the levitation effect is completely negated.
In Bedrock Edition, due to water having collision detection even if the coordinates exceed 8,388,608 blocks, it can be used to travel to the Far Lands without falling through the world.[18]
Bubble columns are created by placing magma blocks or soul sand under water. These can be used to transport mobs or items quickly vertically.