diff --git a/api/s34_sa_gen.py b/api/s34_sa_gen.py
index 4b5cd12..a500f47 100644
--- a/api/s34_sa_gen.py
+++ b/api/s34_sa_gen.py
@@ -1,10 +1,14 @@
 from .s32_region_util import calculate_boundary, inflate_boundary
 from .s34_sa_cal import *
+from .s34_sa import get_all_service_area_ids
 from .batch_exe import execute_batch_command
 
 def generate_service_area(name: str) -> ChangeSet:
     cs = ChangeSet()
 
+    for id in get_all_service_area_ids(name):
+        cs.delete({'type': 'service_area', 'id': id})
+
     sass = calculate_service_area(name)
 
     time_index = 0
diff --git a/test_tjnetwork.py b/test_tjnetwork.py
index 2c8bc0c..d345cdc 100644
--- a/test_tjnetwork.py
+++ b/test_tjnetwork.py
@@ -6181,6 +6181,16 @@ class TestApi:
         assert sa['source'] == 'j1'
         assert sa['nodes'] == ['j1']
 
+        assert get_all_service_area_ids(p) == ['sa']
+        sas = get_all_service_areas(p)
+        assert len(sas) == 1
+        sa = sas[0]
+        assert sa['id'] == 'sa'
+        assert sa['time_index'] == 1
+        assert sa['boundary'] == [(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 0.0)]
+        assert sa['source'] == 'j1'
+        assert sa['nodes'] == ['j1']
+
         delete_service_area(p, ChangeSet({'id': 'sa'}))
         sa = get_service_area(p, 'sa')
         assert sa == {}
@@ -6288,6 +6298,15 @@ class TestApi:
         cs = generate_service_area(p).operations
         assert len(cs) == 78
 
+        assert len(get_all_service_area_ids(p)) == 78
+        assert len(get_all_service_areas(p)) == 78
+
+        cs = generate_service_area(p).operations
+        assert len(cs) == 78 * 2
+
+        assert len(get_all_service_area_ids(p)) == 78
+        assert len(get_all_service_areas(p)) == 78
+
         self.leave(p)