diff --git a/python/ctsm/site_and_regional/single_point_case.py b/python/ctsm/site_and_regional/single_point_case.py
index 448f9d9229..fd7e20a4f2 100644
--- a/python/ctsm/site_and_regional/single_point_case.py
+++ b/python/ctsm/site_and_regional/single_point_case.py
@@ -175,7 +175,7 @@ def check_dom_pft(self):
             - 0 - NAT_PFT-1 range
             or
             - NAT_PFT - MAX_PFT range
-            - give a warning: mixed land units should be checked
+            - give an error: mixed land units not possible
 
         -------------
         Raises:
@@ -183,7 +183,7 @@ def check_dom_pft(self):
                 If any dom_pft is bigger than MAX_PFT.
             Error (ArgumentTypeError):
                 If any dom_pft is less than 1.
-            Warning:
+            Error (ArgumentTypeError):
                 If mixed land units are chosen.
                 dom_pft values are both in range of (0 - NAT_PFT-1) and (NAT_PFT - MAX_PFT).
 
@@ -214,14 +214,12 @@ def check_dom_pft(self):
                 logger.info(
                     "WARNING, you trying to run with generic crops (16 PFT surface dataset)"
                 )
-                # raise argparse.ArgumentTypeError(err_msg)
 
             # -- check if all dom_pft are in the same range:
             if min_dom_pft < NAT_PFT <= max_dom_pft:
                 err_msg = (
-                    "WARNING, you are subsetting using mixed land "
-                    "units that have both natural pfts and crop cfts. Check "
-                    "your surface dataset."
+                    "You are subsetting using mixed land units that have both "
+                    "natural pfts and crop cfts. Check your surface dataset. "
                 )
                 raise argparse.ArgumentTypeError(err_msg)
 
diff --git a/python/ctsm/test/test_unit_singlept_data.py b/python/ctsm/test/test_unit_singlept_data.py
index 7d239c5243..644af82588 100755
--- a/python/ctsm/test/test_unit_singlept_data.py
+++ b/python/ctsm/test/test_unit_singlept_data.py
@@ -225,7 +225,7 @@ def test_check_dom_pft_mixed_range(self):
         single_point.dom_pft = [1, 5, 15]
         single_point.num_pft = 78
         with self.assertRaisesRegex(
-            argparse.ArgumentTypeError, "WARNING, you are subsetting using mixed land*"
+            argparse.ArgumentTypeError, "You are subsetting using mixed land*"
         ):
             single_point.check_dom_pft()