diff --git a/common/lib/xmodule/xmodule/modulestore/inheritance.py b/common/lib/xmodule/xmodule/modulestore/inheritance.py
index 78d584580f..d68c121b96 100644
--- a/common/lib/xmodule/xmodule/modulestore/inheritance.py
+++ b/common/lib/xmodule/xmodule/modulestore/inheritance.py
@@ -56,8 +56,7 @@ def compute_inherited_metadata(descriptor):
         parent_metadata = descriptor.xblock_kvs.inherited_settings.copy()
         # add any of descriptor's explicitly set fields to the inheriting list
         for field in InheritanceMixin.fields.values():
-            # pylint: disable = W0212
-            if descriptor._field_data.has(descriptor, field.name):
+            if field.is_set_on(descriptor):
                 # inherited_settings values are json repr
                 parent_metadata[field.name] = field.read_json(descriptor)
 
diff --git a/common/lib/xmodule/xmodule/modulestore/mongo/base.py b/common/lib/xmodule/xmodule/modulestore/mongo/base.py
index f4c88387f4..44865ab58e 100644
--- a/common/lib/xmodule/xmodule/modulestore/mongo/base.py
+++ b/common/lib/xmodule/xmodule/modulestore/mongo/base.py
@@ -324,16 +324,14 @@ class MongoModuleStore(ModuleStoreBase):
         for result in resultset:
             location = Location(result['_id'])
             # We need to collate between draft and non-draft
-            # i.e. draft verticals can have children which are not in non-draft versions
+            # i.e. draft verticals will have draft children but will have non-draft parents currently
             location = location.replace(revision=None)
             location_url = location.url()
             if location_url in results_by_url:
                 existing_children = results_by_url[location_url].get('definition', {}).get('children', [])
                 additional_children = result.get('definition', {}).get('children', [])
                 total_children = existing_children + additional_children
-                if 'definition' not in results_by_url[location_url]:
-                    results_by_url[location_url]['definition'] = {}
-                results_by_url[location_url]['definition']['children'] = total_children
+                results_by_url[location_url].setdefault('definition', {})['children'] = total_children
             results_by_url[location.url()] = result
             if location.category == 'course':
                 root = location.url()
@@ -643,12 +641,11 @@ class MongoModuleStore(ModuleStoreBase):
         """
         # Save any changes to the xmodule to the MongoKeyValueStore
         xmodule.save()
-        # split mongo's persist_dag is more general and useful.
         self.collection.save({
                 '_id': xmodule.location.dict(),
                 'metadata': own_metadata(xmodule),
                 'definition': {
-                    'data': xmodule.xblock_kvs._data,
+                    'data': xmodule.get_explicitly_set_fields_by_scope(Scope.content),
                     'children': xmodule.children if xmodule.has_children else []
                 }
             })
diff --git a/common/lib/xmodule/xmodule/modulestore/mongo/draft.py b/common/lib/xmodule/xmodule/modulestore/mongo/draft.py
index bed42b30a9..0f46d3fe0c 100644
--- a/common/lib/xmodule/xmodule/modulestore/mongo/draft.py
+++ b/common/lib/xmodule/xmodule/modulestore/mongo/draft.py
@@ -15,6 +15,7 @@ from xmodule.modulestore.inheritance import own_metadata
 from xmodule.modulestore.mongo.base import location_to_query, namedtuple_to_son, get_course_id_no_run, MongoModuleStore
 import pymongo
 from pytz import UTC
+from xblock.fields import Scope
 
 DRAFT = 'draft'
 # Things w/ these categories should never be marked as version='draft'
@@ -237,8 +238,8 @@ class DraftModuleStore(MongoModuleStore):
 
         draft.published_date = datetime.now(UTC)
         draft.published_by = published_by_id
-        super(DraftModuleStore, self).update_item(location, draft._field_data._kvs._data)
-        super(DraftModuleStore, self).update_children(location, draft._field_data._kvs._children)
+        super(DraftModuleStore, self).update_item(location, draft.get_explicitly_set_fields_by_scope(Scope.content))
+        super(DraftModuleStore, self).update_children(location, draft.children)
         super(DraftModuleStore, self).update_metadata(location, own_metadata(draft))
         self.delete_item(location)
 
diff --git a/common/lib/xmodule/xmodule/x_module.py b/common/lib/xmodule/xmodule/x_module.py
index e773c9cc54..3b1254e775 100644
--- a/common/lib/xmodule/xmodule/x_module.py
+++ b/common/lib/xmodule/xmodule/x_module.py
@@ -670,8 +670,8 @@ class XModuleDescriptor(XModuleFields, HTMLSnippet, ResourceTemplates, XBlock):
         """
         result = {}
         for field in self.fields.values():
-            if (field.scope == scope and self._field_data.has(self, field.name)):
-                result[field.name] = self._field_data.get(self, field.name)
+            if (field.scope == scope and field.is_set_on(self)):
+                result[field.name] = field.read_json(self)
         return result
 
     @property