diff --git a/paperwork/api.py b/paperwork/api.py
index d66885a..6369170 100644
--- a/paperwork/api.py
+++ b/paperwork/api.py
@@ -28,7 +28,7 @@ class DepartmentViewSet(viewsets.ModelViewSet):
         Generate a mailing list for each department, containing all
         certified users for tools in that department or child departments
         """
-        departments = self.queryset.filter(has_mailing_list=True).prefetch_related(
+        departments = self.queryset.prefetch_related(
             "children",
             "shop_lead_flag__members",
             Prefetch(
@@ -37,7 +37,7 @@ class DepartmentViewSet(viewsets.ModelViewSet):
             ),
         )
         lists = {}
-        for department in departments:
+        for department in departments.filter(has_mailing_list=True):
             if department.shop_lead_flag is not None:
                 moderator_emails = {
                     member.email for member in department.shop_lead_flag.members.all()
@@ -75,12 +75,12 @@ class DepartmentViewSet(viewsets.ModelViewSet):
                     "members"
                 ]
 
-        for department in departments:
+        for department in departments.filter(has_mailing_list=True):
             if department.parent_id is None:
                 recurse_children(department)
 
         shopleads = {}
-        for department in departments:
+        for department in departments.filter(shop_lead_flag__isnull=False):
             for member in department.shop_lead_flag.members.all():
                 if member not in shopleads:
                     shopleads[member] = []