diff --git a/src/fmu/dataio/_products/inplace_volumes.py b/src/fmu/dataio/_products/inplace_volumes.py
index f3acf4350..f7b5c4828 100644
--- a/src/fmu/dataio/_products/inplace_volumes.py
+++ b/src/fmu/dataio/_products/inplace_volumes.py
@@ -34,7 +34,7 @@ class InplaceVolumesResultRow(BaseModel):
     BULK: float = Field(ge=0.0)
     NET: Optional[float] = Field(default=None, ge=0.0)
     PORV: float = Field(ge=0.0)
-    HCPV: Optional[float] = Field(default=None, ge=0.0)
+    HCPV: float = Field(ge=0.0)
     STOIIP: Optional[float] = Field(default=None, ge=0.0)
     GIIP: Optional[float] = Field(default=None, ge=0.0)
     ASSOCIATEDGAS: Optional[float] = Field(default=None, ge=0.0)
diff --git a/src/fmu/dataio/export/_enums.py b/src/fmu/dataio/export/_enums.py
index 8fdfd4bc5..0007ba357 100644
--- a/src/fmu/dataio/export/_enums.py
+++ b/src/fmu/dataio/export/_enums.py
@@ -43,11 +43,35 @@ def index_columns() -> list[str]:
         """Returns a list of the index columns."""
         return [k.value for k in InplaceVolumes.TableIndexColumns]
 
+    @staticmethod
+    def required_index_columns() -> list[str]:
+        return [
+            InplaceVolumes.TableIndexColumns.FLUID.value,
+            InplaceVolumes.TableIndexColumns.ZONE.value,
+        ]
+
     @staticmethod
     def value_columns() -> list[str]:
         """Returns a list of the value columns."""
         return [k.value for k in InplaceVolumes.VolumetricColumns]
 
+    @staticmethod
+    def required_value_columns() -> list[str]:
+        """Returns a list of the value columns."""
+        return [
+            InplaceVolumes.VolumetricColumns.BULK.value,
+            InplaceVolumes.VolumetricColumns.PORV.value,
+            InplaceVolumes.VolumetricColumns.HCPV.value,
+        ]
+
+    @staticmethod
+    def required_columns() -> list[str]:
+        """Returns a list of the columns required at export."""
+        return (
+            InplaceVolumes.required_index_columns()
+            + InplaceVolumes.required_value_columns()
+        )
+
     @staticmethod
     def table_columns() -> list[str]:
         """Returns a list of all table columns."""
diff --git a/src/fmu/dataio/export/rms/inplace_volumes.py b/src/fmu/dataio/export/rms/inplace_volumes.py
index 6ec6ed18d..32d32b563 100644
--- a/src/fmu/dataio/export/rms/inplace_volumes.py
+++ b/src/fmu/dataio/export/rms/inplace_volumes.py
@@ -261,11 +261,7 @@ def _validate_table(self) -> None:
 
         # create list of missing or non-defined required columns
         missing_calculations = []
-        for col in [
-            _VolumetricColumns.BULK.value,
-            _VolumetricColumns.PORV.value,
-            _VolumetricColumns.HCPV.value,
-        ]:
+        for col in _enums.InplaceVolumes.required_value_columns():
             if self._is_column_missing_in_table(col):
                 missing_calculations.append(col)
 
diff --git a/tests/test_export_rms/test_export_rms_volumetrics.py b/tests/test_export_rms/test_export_rms_volumetrics.py
index 018b02b98..b8dc49ccb 100644
--- a/tests/test_export_rms/test_export_rms_volumetrics.py
+++ b/tests/test_export_rms/test_export_rms_volumetrics.py
@@ -549,3 +549,11 @@ def test_inplace_volumes_export_and_result_columns_are_the_same(
     assert _enums.InplaceVolumes.table_columns() == list(
         InplaceVolumesResultRow.model_fields.keys()
     )
+
+
+def test_that_required_columns_one_to_one_in_enums_and_schema() -> None:
+    schema_required_fields = []
+    for field_name, field_info in InplaceVolumesResultRow.model_fields.items():
+        if field_info.is_required():
+            schema_required_fields.append(field_name)
+    assert _enums.InplaceVolumes.required_columns() == schema_required_fields