diff --git a/jupyterhub/auth.py b/jupyterhub/auth.py
index 9a43d280..ef18fead 100644
--- a/jupyterhub/auth.py
+++ b/jupyterhub/auth.py
@@ -206,6 +206,7 @@ class Authenticator(LoggingConfigurable):
 
     delete_invalid_users = Bool(
         False,
+        config=True,
         help="""Delete any users from the database that do not pass validation
 
         When JupyterHub starts, `.add_user` will be called