diff --git a/src/water_cmd.cpp b/src/water_cmd.cpp
index 3770048ae2..9fb23c47ac 100644
--- a/src/water_cmd.cpp
+++ b/src/water_cmd.cpp
@@ -479,7 +479,7 @@ CommandCost CmdBuildCanal(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 
-	TileIterator *iter = HasBit(p2, 2) ? (TileIterator *)new DiagonalTileIterator(tile, p1) : new OrthogonalTileIterator(tile, p1);
+	std::unique_ptr<TileIterator> iter(HasBit(p2, 2) ? (TileIterator *)new DiagonalTileIterator(tile, p1) : new OrthogonalTileIterator(tile, p1));
 	for (; *iter != INVALID_TILE; ++(*iter)) {
 		TileIndex tile = *iter;
 		CommandCost ret;