diff --git a/python/ctsm/site_and_regional/tower_site.py b/python/ctsm/site_and_regional/tower_site.py
index 82bd7f872d..af3a04e93e 100644
--- a/python/ctsm/site_and_regional/tower_site.py
+++ b/python/ctsm/site_and_regional/tower_site.py
@@ -399,7 +399,7 @@ def run_case(
             if not rundir:
                 rundir = case.get_value("RUNDIR")
 
-            self.modify_user_nl(case_root, run_type, rundir)  # TODO: add site_lines argument?
+            self.modify_user_nl(case_root, run_type, rundir)
 
             case.create_namelists()
             # explicitly run check_input_data