diff --git a/backend/documents_parser/tests/test_extractor.py b/backend/documents_parser/tests/test_extractor.py
index 5da90e8d..d037a6bc 100644
--- a/backend/documents_parser/tests/test_extractor.py
+++ b/backend/documents_parser/tests/test_extractor.py
@@ -407,6 +407,17 @@ class TestWaterHeatingCylinderThickness:
         assert hhw.water_heating.cylinder_size == "Normal (90-130 litres)"
 
 
+class TestImmersionType:
+    @pytest.fixture
+    def hhw(self) -> HeatingAndHotWater:
+        return PasHubRdSapSiteNotesExtractor(
+            load_text_fixture_3()
+        ).extract_heating_and_hot_water()
+
+    def test_immersion_type(self, hhw: HeatingAndHotWater) -> None:
+        assert hhw.water_heating.immersion_type == "Dual"
+
+
 class TestCylinderThermostat:
     @pytest.fixture
     def hhw(self) -> HeatingAndHotWater:
diff --git a/datatypes/epc/surveys/pashub_rdsap_site_notes.py b/datatypes/epc/surveys/pashub_rdsap_site_notes.py
index 1f46b613..1666ca2e 100644
--- a/datatypes/epc/surveys/pashub_rdsap_site_notes.py
+++ b/datatypes/epc/surveys/pashub_rdsap_site_notes.py
@@ -191,6 +191,7 @@ class WaterHeating:
     insulation_type: Optional[str] = None
     insulation_thickness_mm: Optional[int] = None
     has_thermostat: Optional[bool] = None
+    immersion_type: Optional[str] = None
 
 
 @dataclass