diff --git a/source/Generating/FinishGen.cpp b/source/Generating/FinishGen.cpp
index edb213a13..36114fddb 100644
--- a/source/Generating/FinishGen.cpp
+++ b/source/Generating/FinishGen.cpp
@@ -441,6 +441,10 @@ void cFinishGenPreSimulator::CollapseSandGravel(
 						break;
 					}
 					case E_BLOCK_AIR:
+					case E_BLOCK_WATER:
+					case E_BLOCK_STATIONARY_WATER:
+					case E_BLOCK_LAVA:
+					case E_BLOCK_STATIONARY_LAVA:
 					{
 						// Do nothing
 						break;