diff --git a/uvdat/core/rest/access_control.py b/uvdat/core/rest/access_control.py
index dbc52970..684d2394 100644
--- a/uvdat/core/rest/access_control.py
+++ b/uvdat/core/rest/access_control.py
@@ -57,27 +57,13 @@ def has_object_permission(self, request, view, obj):
 
 class GuardianFilter(BaseFilterBackend):
     def filter_queryset(self, request, queryset, view):
-        project_id = request.query_params.get('project')
-        if project_id is not None:
-            try:
-                project_id = int(project_id)
-            except ValueError:
-                project_id = None
-
-        if request.user.is_superuser and project_id is None:
+        if request.user.is_superuser:
             return queryset
 
         # Allow user to have any level of permission
         all_perms = [x for x, _ in Project._meta.permissions]
         user_projects = get_objects_for_user(
-            klass=(
-                models.Project
-                if project_id is None
-                else models.Project.objects.filter(id=project_id)
-            ),
-            user=request.user,
-            perms=all_perms,
-            any_perm=True,
+            klass=models.Project, user=request.user, perms=all_perms, any_perm=True
         )
 
         # Return queryset filtered by objects that are within these projects
diff --git a/uvdat/core/rest/chart.py b/uvdat/core/rest/chart.py
index 12cf5c81..12822e28 100644
--- a/uvdat/core/rest/chart.py
+++ b/uvdat/core/rest/chart.py
@@ -14,6 +14,14 @@ class ChartViewSet(ModelViewSet):
     filter_backends = [GuardianFilter]
     lookup_field = 'id'
 
+    def get_queryset(self):
+        qs = super().get_queryset()
+        project_id: str = self.request.query_params.get('project')
+        if project_id is None or not project_id.isdigit():
+            return qs
+
+        return qs.filter(project=int(project_id))
+
     def validate_editable(self, chart, func, *args, **kwargs):
         if chart.editable:
             return func(*args, **kwargs)
diff --git a/uvdat/core/rest/dataset.py b/uvdat/core/rest/dataset.py
index 24b24402..1ef7eaf9 100644
--- a/uvdat/core/rest/dataset.py
+++ b/uvdat/core/rest/dataset.py
@@ -24,6 +24,14 @@ class DatasetViewSet(ModelViewSet):
     filter_backends = [GuardianFilter]
     lookup_field = 'id'
 
+    def get_queryset(self):
+        qs = super().get_queryset()
+        project_id: str = self.request.query_params.get('project')
+        if project_id is None or not project_id.isdigit():
+            return qs
+
+        return qs.filter(project=int(project_id))
+
     @action(detail=True, methods=['get'])
     def map_layers(self, request, **kwargs):
         dataset: Dataset = self.get_object()
diff --git a/uvdat/core/rest/regions.py b/uvdat/core/rest/regions.py
index 00781227..d3a6496c 100644
--- a/uvdat/core/rest/regions.py
+++ b/uvdat/core/rest/regions.py
@@ -32,19 +32,20 @@ class DerivedRegionViewSet(mixins.RetrieveModelMixin, mixins.ListModelMixin, Gen
     filter_backends = [GuardianFilter]
     lookup_field = 'id'
 
+    def get_queryset(self):
+        qs = super().get_queryset()
+        project_id: str = self.request.query_params.get('project')
+        if project_id is None or not project_id.isdigit():
+            return qs
+
+        return qs.filter(project=int(project_id))
+
     def get_serializer_class(self):
         if self.detail:
             return DerivedRegionDetailSerializer
 
         return super().get_serializer_class()
 
-    def get_queryset(self):
-        project_id = self.request.query_params.get('project')
-        if project_id:
-            return DerivedRegion.objects.filter(project__id=project_id)
-        else:
-            return DerivedRegion.objects.all()
-
     @action(detail=True, methods=['GET'])
     def as_feature(self, request, *args, **kwargs):
         obj: DerivedRegion = self.get_object()