Waterlogging

Waterlogging is the mechanic that allows non-cube blocks (that is, blocks that do not completely fill their block volume, such as ladders, fences, and plants) to be filled with a water source block. Both the non-cube block and the water source block occupy the same space. If the non-cube block is destroyed, the water source block still remains in the original spot it came from.

In Bedrock Edition, generally all non-cube blocks can be waterlogged and none can be used to displace water source blocks, although they can still displace flowing water.

In Java Edition, certain blocks have a waterlogged block state that can be true, or false. If a waterlogged block is pushed by a piston or sticky piston, the waterlogged state of the block is typically removed. However, if a sticky piston gets powered by a short pulse so that the sticky piston spits out the block when pulling, the block retains its waterlogged state.