diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 4e328ac76..774b1e992 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -4002,6 +4002,13 @@ Definition tables
         ^ Node destructor; called after removing node
         ^ Not called for bulk node placement (i.e. schematics and VoxelManip)
         ^ default: nil ]]
+        on_flood = func(pos, oldnode, newnode), --[[
+        ^ Called when a liquid (newnode) is about to flood oldnode, if
+        ^ it has `floodable = true` in the nodedef. Not called for bulk
+        ^ node placement (i.e. schematics and VoxelManip) or air nodes. If
+        ^ return true the node is not flooded, but on_flood callback will
+        ^ most likely be called over and over again every liquid update
+        ^ interval. Default: nil ]]
 
         after_place_node = func(pos, placer, itemstack, pointed_thing) --[[
         ^ Called after constructing node when node was placed using
diff --git a/src/map.cpp b/src/map.cpp
index 8754813dd..75dcee350 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -44,6 +44,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "database.h"
 #include "database-dummy.h"
 #include "database-sqlite3.h"
+#include "script/serverscripting.h"
 #include <deque>
 #include <queue>
 #if USE_LEVELDB
@@ -637,7 +638,8 @@ s32 Map::transforming_liquid_size() {
         return m_transforming_liquid.size();
 }
 
-void Map::transformLiquids(std::map<v3s16, MapBlock*> &modified_blocks)
+void Map::transformLiquids(std::map<v3s16, MapBlock*> &modified_blocks,
+		ServerEnvironment *env)
 {
 	DSTACK(FUNCTION_NAME);
 	//TimeTaker timer("transformLiquids()");
@@ -897,8 +899,16 @@ void Map::transformLiquids(std::map<v3s16, MapBlock*> &modified_blocks)
 			// set the liquid level and flow bit to 0
 			n0.param2 = ~(LIQUID_LEVEL_MASK | LIQUID_FLOW_DOWN_MASK);
 		}
+
+		// change the node.
 		n0.setContent(new_node_content);
 
+		// on_flood() the node
+		if (floodable_node != CONTENT_AIR) {
+			if (env->getScriptIface()->node_on_flood(p0, n00, n0))
+				continue;
+		}
+
 		// Ignore light (because calling voxalgo::update_lighting_nodes)
 		n0.setLight(LIGHTBANK_DAY, 0, m_nodedef);
 		n0.setLight(LIGHTBANK_NIGHT, 0, m_nodedef);
diff --git a/src/map.h b/src/map.h
index 739cdb59b..4d7079823 100644
--- a/src/map.h
+++ b/src/map.h
@@ -266,7 +266,8 @@ public:
 	// For debug printing. Prints "Map: ", "ServerMap: " or "ClientMap: "
 	virtual void PrintInfo(std::ostream &out);
 
-	void transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks);
+	void transformLiquids(std::map<v3s16, MapBlock*> & modified_blocks,
+			ServerEnvironment *env);
 
 	/*
 		Node metadata
diff --git a/src/script/cpp_api/s_node.cpp b/src/script/cpp_api/s_node.cpp
index adad01e45..2723f84e1 100644
--- a/src/script/cpp_api/s_node.cpp
+++ b/src/script/cpp_api/s_node.cpp
@@ -178,6 +178,27 @@ void ScriptApiNode::node_on_destruct(v3s16 p, MapNode node)
 	lua_pop(L, 1);  // Pop error handler
 }
 
+bool ScriptApiNode::node_on_flood(v3s16 p, MapNode node, MapNode newnode)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	int error_handler = PUSH_ERROR_HANDLER(L);
+
+	INodeDefManager *ndef = getServer()->ndef();
+
+	// Push callback function on stack
+	if (!getItemCallback(ndef->get(node).name.c_str(), "on_flood"))
+		return false;
+
+	// Call function
+	push_v3s16(L, p);
+	pushnode(L, node, ndef);
+	pushnode(L, newnode, ndef);
+	PCALL_RES(lua_pcall(L, 3, 1, error_handler));
+	lua_remove(L, error_handler);
+	return (bool) lua_isboolean(L, -1) && (bool) lua_toboolean(L, -1) == true;
+}
+
 void ScriptApiNode::node_after_destruct(v3s16 p, MapNode node)
 {
 	SCRIPTAPI_PRECHECKHEADER
diff --git a/src/script/cpp_api/s_node.h b/src/script/cpp_api/s_node.h
index fe1180cb3..eb127909d 100644
--- a/src/script/cpp_api/s_node.h
+++ b/src/script/cpp_api/s_node.h
@@ -42,6 +42,7 @@ public:
 			ServerActiveObject *digger);
 	void node_on_construct(v3s16 p, MapNode node);
 	void node_on_destruct(v3s16 p, MapNode node);
+	bool node_on_flood(v3s16 p, MapNode node, MapNode newnode);
 	void node_after_destruct(v3s16 p, MapNode node);
 	bool node_on_timer(v3s16 p, MapNode node, f32 dtime);
 	void node_on_receive_fields(v3s16 p,
diff --git a/src/server.cpp b/src/server.cpp
index a921423d2..ac6265d09 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -599,7 +599,7 @@ void Server::AsyncRunStep(bool initial_step)
 		ScopeProfiler sp(g_profiler, "Server: liquid transform");
 
 		std::map<v3s16, MapBlock*> modified_blocks;
-		m_env->getMap().transformLiquids(modified_blocks);
+		m_env->getMap().transformLiquids(modified_blocks, m_env);
 #if 0
 		/*
 			Update lighting