--- a/net/minecraft/world/level/material/FluidTypeFlowing.java
+++ b/net/minecraft/world/level/material/FluidTypeFlowing.java
@@ -32,6 +32,15 @@
 import net.minecraft.world.phys.shapes.VoxelShape;
 import net.minecraft.world.phys.shapes.VoxelShapes;
 
+// CraftBukkit start
+import org.bukkit.block.BlockFace;
+import org.bukkit.craftbukkit.block.CraftBlock;
+import org.bukkit.craftbukkit.block.data.CraftBlockData;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.event.block.BlockFromToEvent;
+import org.bukkit.event.block.FluidLevelChangeEvent;
+// CraftBukkit end
+
 public abstract class FluidTypeFlowing extends FluidType {
 
     public static final BlockStateBoolean FALLING = BlockProperties.FALLING;
@@ -135,6 +144,15 @@
                 FluidType fluidtype = fluid2.getType();
 
                 if (fluid1.canBeReplacedWith(worldserver, blockposition1, fluidtype, EnumDirection.DOWN) && canHoldSpecificFluid(worldserver, blockposition1, iblockdata1, fluidtype)) {
+                    // CraftBukkit start
+                    org.bukkit.block.Block source = CraftBlock.at(worldserver, blockposition);
+                    BlockFromToEvent event = new BlockFromToEvent(source, BlockFace.DOWN);
+                    worldserver.getCraftServer().getPluginManager().callEvent(event);
+
+                    if (event.isCancelled()) {
+                        return;
+                    }
+                    // CraftBukkit end
                     this.spreadTo(worldserver, blockposition1, iblockdata1, EnumDirection.DOWN, fluid2);
                     if (this.sourceNeighborCount(worldserver, blockposition) >= 3) {
                         this.spreadToSides(worldserver, blockposition, fluid, iblockdata);
@@ -168,6 +186,15 @@
                 Fluid fluid1 = (Fluid) entry.getValue();
                 BlockPosition blockposition1 = blockposition.relative(enumdirection);
 
+                // CraftBukkit start
+                org.bukkit.block.Block source = CraftBlock.at(worldserver, blockposition);
+                BlockFromToEvent event = new BlockFromToEvent(source, org.bukkit.craftbukkit.block.CraftBlock.notchToBlockFace(enumdirection));
+                worldserver.getCraftServer().getPluginManager().callEvent(event);
+
+                if (event.isCancelled()) {
+                    continue;
+                }
+                // CraftBukkit end
                 this.spreadTo(worldserver, blockposition1, worldserver.getBlockState(blockposition1), enumdirection, fluid1);
             }
 
@@ -444,10 +471,24 @@
             if (fluid1.isEmpty()) {
                 fluid = fluid1;
                 iblockdata = Blocks.AIR.defaultBlockState();
+                // CraftBukkit start
+                FluidLevelChangeEvent event = CraftEventFactory.callFluidLevelChangeEvent(worldserver, blockposition, iblockdata);
+                if (event.isCancelled()) {
+                    return;
+                }
+                iblockdata = ((CraftBlockData) event.getNewData()).getState();
+                // CraftBukkit end
                 worldserver.setBlock(blockposition, iblockdata, 3);
             } else if (!fluid1.equals(fluid)) {
                 fluid = fluid1;
                 iblockdata = fluid1.createLegacyBlock();
+                // CraftBukkit start
+                FluidLevelChangeEvent event = CraftEventFactory.callFluidLevelChangeEvent(worldserver, blockposition, iblockdata);
+                if (event.isCancelled()) {
+                    return;
+                }
+                iblockdata = ((CraftBlockData) event.getNewData()).getState();
+                // CraftBukkit end
                 worldserver.setBlock(blockposition, iblockdata, 3);
                 worldserver.scheduleTick(blockposition, fluid1.getType(), i);
             }
