Minecraft wiki entry for Lily_Pad, associated text: When lily pads are placed on water source blocks that do not take up the space of the entire block (when the water is flowing to the block next to it), the lily pad appears floating above the water source block.
Lily pads are the only block whose height is not a multiple of 1/16 (size of one pixel on the default texture pack). It is 1.5 pixels high, or 0.09375 or 3/32 blocks high.
If the player sprints[verify] or falls on lily pads, they appear to give off water particles. This is because the game thinks the player is technically on the water below the lily pad.[8][9]