diff --git a/src/BTCSBoundaryCondition.cpp b/src/BTCSBoundaryCondition.cpp
index ec46c1d..eef46be 100644
--- a/src/BTCSBoundaryCondition.cpp
+++ b/src/BTCSBoundaryCondition.cpp
@@ -3,7 +3,7 @@
 #include <vector>
 
 #include "grid/BTCSBoundaryCondition.hpp"
-#include "diffusion/BTCSUtils.hpp"
+#include "BTCSUtils.hpp"
 
 constexpr uint8_t DIM_1D = 2;
 constexpr uint8_t DIM_2D = 4;
diff --git a/include/diffusion/BTCSUtils.hpp b/src/BTCSUtils.hpp
similarity index 100%
rename from include/diffusion/BTCSUtils.hpp
rename to src/BTCSUtils.hpp