diff --git a/neutron/quota/resource_registry.py b/neutron/quota/resource_registry.py
index 21df72285c1..a917eacc06c 100644
--- a/neutron/quota/resource_registry.py
+++ b/neutron/quota/resource_registry.py
@@ -36,6 +36,12 @@ def get_all_resources():
     return ResourceRegistry.get_instance().resources
 
 
+def unregister_all_resources():
+    if not ResourceRegistry._instance:
+        return
+    return ResourceRegistry.get_instance().unregister_resources()
+
+
 def get_resource(resource_name):
     return ResourceRegistry.get_instance().get_resource(resource_name)
 
@@ -183,6 +189,10 @@ class ResourceRegistry(object):
         if not cfg.CONF.QUOTAS.track_quota_usage:
             return
 
+        if isinstance(self._resources.get(resource_name),
+                      resource.CountableResource):
+            raise RuntimeError("Resource %s is already registered as a "
+                               "countable resource." % resource_name)
         current_model_class = self._tracked_resource_mappings.setdefault(
             resource_name, model_class)
 
diff --git a/neutron/tests/base.py b/neutron/tests/base.py
index 49f712b11e1..b5400bce7b0 100644
--- a/neutron/tests/base.py
+++ b/neutron/tests/base.py
@@ -46,6 +46,7 @@ from neutron.common import utils
 from neutron.db import agentschedulers_db
 from neutron import manager
 from neutron import policy
+from neutron.quota import resource_registry
 from neutron.tests import fake_notifier
 from neutron.tests import post_mortem_debug
 from neutron.tests import tools
@@ -302,6 +303,7 @@ class BaseTestCase(DietTestCase):
 
         policy.init()
         self.addCleanup(policy.reset)
+        self.addCleanup(resource_registry.unregister_all_resources)
         self.addCleanup(rpc_consumer_reg.clear)
 
     def get_new_temp_dir(self):
diff --git a/neutron/tests/unit/quota/test_resource_registry.py b/neutron/tests/unit/quota/test_resource_registry.py
index 5f265a8833d..52ead4efced 100644
--- a/neutron/tests/unit/quota/test_resource_registry.py
+++ b/neutron/tests/unit/quota/test_resource_registry.py
@@ -14,6 +14,7 @@
 
 import mock
 from oslo_config import cfg
+import testtools
 
 from neutron import context
 from neutron.quota import resource
@@ -64,6 +65,13 @@ class TestResourceRegistry(base.DietTestCase):
     def test_register_resource_by_name_not_tracked(self):
         self._test_register_resource_by_name('meh', resource.CountableResource)
 
+    def test_tracked_resource_error_if_already_registered_as_untracked(self):
+        self.registry.register_resource_by_name('meh')
+        with testtools.ExpectedException(RuntimeError):
+            self.registry.set_tracked_resource('meh', test_quota.MehModel)
+        # ensure unregister works
+        self.registry.unregister_resources()
+
     def test_register_resource_by_name_with_tracking_disabled_by_config(self):
         cfg.CONF.set_override('track_quota_usage', False,
                               group='QUOTAS')