diff --git a/app/models/notification_type.rb b/app/models/notification_type.rb
index 11230db24..54503aa56 100644
--- a/app/models/notification_type.rb
+++ b/app/models/notification_type.rb
@@ -42,6 +42,7 @@ class NotificationType
     notify_admin_export_complete
     notify_member_about_coupon
     notify_member_reservation_reminder
+    notify_admin_free_disk_space
   ]
   # deprecated:
   # - notify_member_subscribed_plan_is_changed