diff --git a/quantum/db/db_base_plugin_v2.py b/quantum/db/db_base_plugin_v2.py
index 36d1356c56..b5dce8bcc4 100644
--- a/quantum/db/db_base_plugin_v2.py
+++ b/quantum/db/db_base_plugin_v2.py
@@ -46,7 +46,7 @@ AGENT_OWNER_PREFIX = 'network:'
 # finds out that all existing IP Allocations are associated with ports
 # with these owners, it will allow subnet deletion to proceed with the
 # IP allocations being cleaned up by cascade.
-AUTO_DELETE_PORT_OWNERS = ['network:dhcp', 'network:router_interface']
+AUTO_DELETE_PORT_OWNERS = ['network:dhcp']
 
 
 class QuantumDbPluginV2(quantum_plugin_base_v2.QuantumPluginBaseV2):
diff --git a/quantum/tests/unit/openvswitch/test_agent_scheduler.py b/quantum/tests/unit/openvswitch/test_agent_scheduler.py
index 4c80ca15b4..d44b12968a 100644
--- a/quantum/tests/unit/openvswitch/test_agent_scheduler.py
+++ b/quantum/tests/unit/openvswitch/test_agent_scheduler.py
@@ -602,6 +602,16 @@ class OvsAgentSchedulerTestCase(test_l3_plugin.L3NatTestCaseMixin,
                 router1['router']['id'])
             l3_agents_2 = self._list_l3_agents_hosting_router(
                 router2['router']['id'])
+            # safe cleanup
+            self._router_interface_action('remove',
+                                          router1['router']['id'],
+                                          subnet1['subnet']['id'],
+                                          None)
+            self._router_interface_action('remove',
+                                          router2['router']['id'],
+                                          subnet2['subnet']['id'],
+                                          None)
+
         # L3 agent will host only the compatible router.
         self.assertEqual(1, num_hosta_routers)
         self.assertEqual(1, len(l3_agents_1['agents']))
diff --git a/quantum/tests/unit/test_l3_plugin.py b/quantum/tests/unit/test_l3_plugin.py
index 64463141be..703686b24e 100644
--- a/quantum/tests/unit/test_l3_plugin.py
+++ b/quantum/tests/unit/test_l3_plugin.py
@@ -969,23 +969,6 @@ class L3NatDBTestCase(L3NatTestCaseBase):
                     r['router']['id'],
                     n['network']['id'], expected_code=exc.HTTPBadRequest.code)
 
-    def test_delete_unused_router_interface(self):
-        with self.network() as n:
-            with self.router() as r:
-                with self.subnet(network=n) as s:
-                    res = self._create_port(self.fmt,
-                                            s['subnet']['network_id'])
-                    p = self.deserialize(self.fmt, res)
-                    self._router_interface_action('add',
-                                                  r['router']['id'],
-                                                  None,
-                                                  p['port']['id'])
-                # The subnet here is deleted, and the port should have no IP
-                self._delete('ports', p['port']['id'])
-                # Verify the port has been deleted
-                self._show('ports', p['port']['id'],
-                           expected_code=exc.HTTPNotFound.code)
-
     def test_router_remove_interface_inuse_returns_409(self):
         with self.router() as r:
             with self.subnet() as s:
@@ -1635,6 +1618,22 @@ class L3NatDBTestCase(L3NatTestCaseBase):
             self.assertTrue(floatingips[0]['fixed_ip_address'] is not None)
             self.assertTrue(floatingips[0]['router_id'] is not None)
 
+    def test_router_delete_subnet_inuse_returns_409(self):
+        with self.router() as r:
+            with self.subnet() as s:
+                self._router_interface_action('add',
+                                              r['router']['id'],
+                                              s['subnet']['id'],
+                                              None)
+                # subnet cannot be delete as it's attached to a router
+                self._delete('subnets', s['subnet']['id'],
+                             expected_code=exc.HTTPConflict.code)
+                # remove interface so test can exit without errors
+                self._router_interface_action('remove',
+                                              r['router']['id'],
+                                              s['subnet']['id'],
+                                              None)
+
 
 class L3NatDBTestCaseXML(L3NatDBTestCase):
     fmt = 'xml'