diff --git a/repositories/plan/plan_postgres_repository.py b/repositories/plan/plan_postgres_repository.py
index c2685ace4..aa1e30157 100644
--- a/repositories/plan/plan_postgres_repository.py
+++ b/repositories/plan/plan_postgres_repository.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 from typing import Any
 
 from sqlalchemy import insert as _sa_insert
-from sqlmodel import Session, col, update
+from sqlmodel import Session, col, select, update
 
 from domain.modelling.plan import Plan
 from infrastructure.postgres.modelling import PlanModel, RecommendationModel
@@ -46,7 +46,15 @@ class PlanPostgresRepository(PlanRepository):
         )[0]
 
     def property_ids_with_default_plans(self, property_ids: list[int]) -> set[int]:
-        raise NotImplementedError
+        rows = self._session.exec(
+            select(col(PlanModel.property_id))
+            .distinct()
+            .where(
+                col(PlanModel.property_id).in_(property_ids),
+                col(PlanModel.is_default).is_(True),
+            )
+        ).all()
+        return {int(row) for row in rows}
 
     def save_batch(self, requests: list[PlanSaveRequest]) -> list[int]:
         """Persist all Plans in three statements regardless of batch size.