diff --git a/include/openmc/material.h b/include/openmc/material.h
index 8771b372a..70c6b3852 100644
--- a/include/openmc/material.h
+++ b/include/openmc/material.h
@@ -120,7 +120,7 @@ public:
   //! Assign a unique ID to the material
   //! \param[in] Unique ID to assign. A value of -1 indicates that an ID
   //!   should be automatically assigned.
-  void set_id(int32_t id = -1);
+  void set_id(int32_t id);
 
   //! Get whether material is fissionable
   //! \return Whether material is fissionable
diff --git a/include/openmc/tallies/filter.h b/include/openmc/tallies/filter.h
index b25110e07..ba6ca0883 100644
--- a/include/openmc/tallies/filter.h
+++ b/include/openmc/tallies/filter.h
@@ -104,7 +104,7 @@ public:
   //! Assign a unique ID to the filter
   //! \param[in]  Unique ID to assign. A value of -1 indicates that an ID should
   //!   be automatically assigned
-  void set_id(int32_t id = -1);
+  void set_id(int32_t id);
 
   //! Get number of bins
   //! \return Number of bins