diff --git a/infrastructure/postgres/epc_property_table.py b/infrastructure/postgres/epc_property_table.py
index 512621d6c..f77128799 100644
--- a/infrastructure/postgres/epc_property_table.py
+++ b/infrastructure/postgres/epc_property_table.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from typing import ClassVar, Optional, Union
-from sqlalchemy import Column
+from sqlalchemy import BigInteger, Column
 from sqlalchemy import Enum as SAEnum
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlmodel import SQLModel, Field
@@ -36,7 +36,12 @@ class EpcPropertyModel(SQLModel, table=True):
     source: str = Field(default="lodged")
 
     # Identity / admin
-    uprn: Optional[int] = Field(default=None)
+    # BIGINT: real 12-digit UPRNs overflow int32 (the FE `property.uprn` is
+    # already bigint). SQLModel maps `int` -> INTEGER by default, so pin the
+    # column type or every real-UPRN insert hard-fails NumericValueOutOfRange.
+    uprn: Optional[int] = Field(
+        default=None, sa_column=Column(BigInteger, nullable=True)
+    )
     uprn_source: Optional[str] = Field(default=None)
     report_reference: Optional[str] = Field(default=None)
     report_type: Optional[str] = Field(default=None)