diff --git a/src/sink/GEAR/sink_iact.h b/src/sink/GEAR/sink_iact.h
index 0041664d2246b8777bdef22d5648af3d80424fc0..71b59fa786937397e6bcd1f903ff4b720fb92eee 100644
--- a/src/sink/GEAR/sink_iact.h
+++ b/src/sink/GEAR/sink_iact.h
@@ -22,6 +22,7 @@
 /* Local includes */
 #include "gravity.h"
 #include "gravity_iact.h"
+#include "sink_properties.h"
 
 /**
  * @brief do sink computation after the runner_iact_density (symmetric