diff --git a/.docs/Notebooks/mf6_complex_model_example.py b/.docs/Notebooks/mf6_complex_model_example.py
index f999b00d96..572626f87a 100644
--- a/.docs/Notebooks/mf6_complex_model_example.py
+++ b/.docs/Notebooks/mf6_complex_model_example.py
@@ -237,7 +237,6 @@
             0.5,
             0.3,
             0.1,
-            None,
         )
 evt = flopy.mf6.ModflowGwfevt(
     gwf,
diff --git a/autotest/regression/test_mf6.py b/autotest/regression/test_mf6.py
index e1c5850887..96709436d9 100644
--- a/autotest/regression/test_mf6.py
+++ b/autotest/regression/test_mf6.py
@@ -1528,7 +1528,6 @@ def test005_create_tests_advgw_tidal(function_tmpdir, example_data_path):
                 50.0,
                 0.0004,
                 10.0,
-                None,
             )
     evt_package_test = ModflowGwfevt(
         model,
@@ -1554,7 +1553,6 @@ def test005_create_tests_advgw_tidal(function_tmpdir, example_data_path):
                 0.5,
                 0.3,
                 0.1,
-                None,
             )
     evt_package = ModflowGwfevt(
         model,
diff --git a/flopy/mf6/data/mfdatastorage.py b/flopy/mf6/data/mfdatastorage.py
index 8a57413538..ec2094fdc8 100644
--- a/flopy/mf6/data/mfdatastorage.py
+++ b/flopy/mf6/data/mfdatastorage.py
@@ -2710,7 +2710,13 @@ def build_type_list(
                                 self._append_type_lists(
                                     aux_var_name, data_type, False
                                 )
-
+                elif data_item.name == "petm0" and resolve_data_shape:
+                    for key in self._simulation_data.mfdata:
+                        if "surf_rate_specified" in key:
+                            if self._simulation_data.mfdata[key].get_data():
+                                self._append_type_lists(
+                                    data_item.name, data_type, False
+                                )
                 elif data_item.type == DatumType.record:
                     # record within a record, recurse
                     self.build_type_list(data_item, True, data)
diff --git a/flopy/mf6/data/mffileaccess.py b/flopy/mf6/data/mffileaccess.py
index e64ed695d6..9127d8d4ec 100644
--- a/flopy/mf6/data/mffileaccess.py
+++ b/flopy/mf6/data/mffileaccess.py
@@ -1130,15 +1130,43 @@ def _get_header(self):
                 else:
                     header.append((di_struct.name, np_flt_type))
                 ext_index += 1
-            elif di_struct.name == "aux":
-                aux_var_names = (
-                    self._data_dimensions.package_dim.get_aux_variables()
-                )
-                if aux_var_names is not None:
-                    for aux_var_name in aux_var_names[0]:
-                        if aux_var_name.lower() != "auxiliary":
-                            header.append((aux_var_name, np_flt_type))
-                            ext_index += 1
+            else:
+                # optional tags
+                if di_struct.name == "aux":
+                    aux_var_names = (
+                        self._data_dimensions.package_dim.get_aux_variables()
+                    )
+                    if aux_var_names is not None:
+                        for aux_var_name in aux_var_names[0]:
+                            if aux_var_name.lower() != "auxiliary":
+                                header.append((aux_var_name, np_flt_type))
+                                ext_index += 1
+                elif di_struct.name == "petm0":
+                    for key in self._simulation_data.mfdata:
+                        if "surf_rate_specified" in key:
+                            if self._simulation_data.mfdata[key].get_data():
+                                header.append((di_struct.name, np_flt_type))
+                                ext_index += 1
+                elif di_struct.name == "pxdp" or di_struct.name == "petm":
+                    for key in self._simulation_data.mfdata:
+                        if "nseg" in key:
+                            if (
+                                self._simulation_data.mfdata[key].get_data()
+                                > 1
+                            ):
+                                for seg in range(
+                                    self._simulation_data.mfdata[
+                                        key
+                                    ].get_data()
+                                    - 1
+                                ):
+                                    header.append(
+                                        (
+                                            f"{di_struct.name}{seg+1}",
+                                            np_flt_type,
+                                        )
+                                    )
+                                    ext_index += 1
         return header, int_cellid_indexes, ext_cellid_indexes
 
     def _get_cell_header(self, data_item, data_set, index):