diff --git a/rmw/include/rmw/event.h b/rmw/include/rmw/event.h
index 707ccca9..944ee87e 100644
--- a/rmw/include/rmw/event.h
+++ b/rmw/include/rmw/event.h
@@ -32,6 +32,9 @@ extern "C"
 /// Define publisher/subscription events
 typedef enum rmw_event_type_e
 {
+  // initial value
+  RMW_EVENT_INVALID,
+
   // subscription events
   RMW_EVENT_LIVELINESS_CHANGED,
   RMW_EVENT_REQUESTED_DEADLINE_MISSED,
@@ -48,7 +51,7 @@ typedef enum rmw_event_type_e
   RMW_EVENT_PUBLICATION_MATCHED,
 
   // sentinel value
-  RMW_EVENT_INVALID
+  RMW_EVENT_TYPE_MAX
 } rmw_event_type_t;
 
 /// Encapsulate the RMW event implementation, data, and type.
diff --git a/rmw/test/test_event.cpp b/rmw/test/test_event.cpp
index 980f5dc1..5ac5c7af 100644
--- a/rmw/test/test_event.cpp
+++ b/rmw/test/test_event.cpp
@@ -20,7 +20,7 @@ TEST(rmw_event, get_zero_initialized_event)
   const rmw_event_t actual = rmw_get_zero_initialized_event();
   EXPECT_EQ(nullptr, actual.implementation_identifier);
   EXPECT_EQ(nullptr, actual.data);
-  EXPECT_EQ(0u, actual.event_type);
+  EXPECT_EQ(RMW_EVENT_INVALID, actual.event_type);
 }
 
 TEST(rmw_event, event_fini)
@@ -36,5 +36,5 @@ TEST(rmw_event, event_fini)
   EXPECT_EQ(rmw_event_fini(&event), RMW_RET_OK);
   EXPECT_EQ(nullptr, event.implementation_identifier);
   EXPECT_EQ(nullptr, event.data);
-  EXPECT_EQ(0u, event.event_type);
+  EXPECT_EQ(RMW_EVENT_INVALID, event.event_type);
 }