diff --git a/hydromt_fiat/workflows/aggregation_areas.py b/hydromt_fiat/workflows/aggregation_areas.py
index 49b54b2e..1bd63ddf 100644
--- a/hydromt_fiat/workflows/aggregation_areas.py
+++ b/hydromt_fiat/workflows/aggregation_areas.py
@@ -159,13 +159,13 @@ def spatial_joins(
 
         # Create new object_ids
         init_Object_ID = exposure_gdf_copy.loc[0, "object_name"]
-        init_Object_ID = int(init_Object_ID.split(": ", 1)[1])
+        init_Object_ID = int(init_Object_ID.split(":", 1)[1])
         exposure_gdf.loc[0:, "object_id"] = np.arange(
             init_Object_ID, init_Object_ID + int(len(exposure_gdf)), 1
         ).tolist()
         # Create new object_names
         exposure_gdf["object_name"] = exposure_gdf["object_id"].apply(
-            lambda x: f"New development area: {int(x)}"
+            lambda x: f"new_develpoment_area:{int(x)}"
         )
 
         # Split max potential damages into new composite areas
diff --git a/hydromt_fiat/workflows/exposure_vector.py b/hydromt_fiat/workflows/exposure_vector.py
index 9a404dd5..9b014bc4 100644
--- a/hydromt_fiat/workflows/exposure_vector.py
+++ b/hydromt_fiat/workflows/exposure_vector.py
@@ -1634,9 +1634,9 @@ def setup_new_composite_areas(
 
             dict_new_objects_data = {
                 "object_id": [new_id],
-                "object_name": ["New development area: " + str(new_id)],
-                "primary_object_type": ["New development area"],
-                "secondary_object_type": ["New development area"],
+                "object_name": ["new_development_area:" + str(new_id)],
+                "primary_object_type": ["new_development_area:"],
+                "secondary_object_type": ["new_development_area:"],
                 "extract_method": ["area"],
                 "ground_flht": [0],
                 "ground_elevtn": [0],
diff --git a/tests/test_setup_new_composite_area_divided_aggregation.py b/tests/test_setup_new_composite_area_divided_aggregation.py
index 0f318d32..dfa22353 100644
--- a/tests/test_setup_new_composite_area_divided_aggregation.py
+++ b/tests/test_setup_new_composite_area_divided_aggregation.py
@@ -86,7 +86,7 @@ def test_setup_new_composite_areas_ground_elevation_aggregation(case):
 
     # Check if max potentail damages are divided correctly
     exposure_new_composite = exposure_modified[
-        exposure_modified["primary_object_type"] == "New development area"
+        exposure_modified["primary_object_type"] == "new_development_area"
     ]
     assert round(sum([38142538.34, 13528445.7])) == round(
         sum(exposure_new_composite["max_damage_content"].values)