diff --git a/backend/app/modelling/property_filters.py b/backend/app/modelling/property_filters.py
index 8c5a26e8f..4f45c6325 100644
--- a/backend/app/modelling/property_filters.py
+++ b/backend/app/modelling/property_filters.py
@@ -43,14 +43,17 @@ def resolve_filtered_property_ids(
     portfolio's rows with ``marked_for_deletion = false``; property_type /
     built_form resolve override → lodged EPC → predicted EPC → legacy columns
     → "Unknown"."""
-    rows = session.exec(
+    statement = (
         select(PropertyRow)
         .where(PropertyRow.portfolio_id == portfolio_id)
         # IS NOT TRUE rather than == False: the FE schema defaults the flag,
         # but a NULL must never silently exclude a property.
         .where(col(PropertyRow.marked_for_deletion).isnot(True))
         .order_by(col(PropertyRow.id))
-    ).all()
+    )
+    if filters.postcodes is not None:
+        statement = statement.where(col(PropertyRow.postcode).in_(filters.postcodes))
+    rows = session.exec(statement).all()
     return [
         FilteredProperty(property_id=row.id, postcode=row.postcode)
         for row in rows