Minecraft wiki entry for Fluid, associated text: Flowing fluid has a speed value that governs how fast the spreading effect takes place. Water in the Overworld and lava in the Nether move at the same speed of 1 block every 5 ticks, or 4 blocks per second. However, lava in the Overworld is much slower than water, and moves at only 1 block every 30 game ticks, or 2 blocks every 3 seconds. Note that in Bedrock Edition, fluids may flow faster than they should, especially if an adjacent observer is repeatedly activating, due to MCPE-73342.