diff --git a/designate/central/service.py b/designate/central/service.py
index f3f81b919..c9e05624a 100644
--- a/designate/central/service.py
+++ b/designate/central/service.py
@@ -470,6 +470,8 @@ class Service(service.RPCService, service.Service):
         return subzones
 
     def _is_valid_ttl(self, context, ttl):
+        if ttl is None:
+            return
         min_ttl = cfg.CONF['service:central'].min_ttl
         if min_ttl is not None and ttl < int(min_ttl):
             try:
@@ -846,8 +848,7 @@ class Service(service.RPCService, service.Service):
         self._is_valid_zone_name(context, zone.name)
 
         # Ensure TTL is above the minimum
-        if zone.ttl is not None:
-            self._is_valid_ttl(context, zone.ttl)
+        self._is_valid_ttl(context, zone.ttl)
 
         # Get a pool id
         zone.pool_id = self.scheduler.schedule_zone(context, zone)
@@ -1026,9 +1027,8 @@ class Service(service.RPCService, service.Service):
             raise exceptions.BadRequest('Renaming a zone is not allowed')
 
         # Ensure TTL is above the minimum
-        ttl = changes.get('ttl', None)
-        if ttl is not None:
-            self._is_valid_ttl(context, ttl)
+        ttl = changes.get('ttl')
+        self._is_valid_ttl(context, ttl)
 
         return self._update_zone(context, zone, increment_serial, changes)
 
@@ -1268,8 +1268,7 @@ class Service(service.RPCService, service.Service):
             changes = recordset.obj_get_changes()
             ttl = changes.get('ttl', None)
 
-        if ttl is not None:
-            self._is_valid_ttl(context, ttl)
+        self._is_valid_ttl(context, ttl)
 
         # Ensure the recordset name and placement is valid
         self._is_valid_recordset_name(context, zone, recordset.name)
diff --git a/designate/tests/unit/test_central/test_basic.py b/designate/tests/unit/test_central/test_basic.py
index eeaf68f49..fdfe7b143 100644
--- a/designate/tests/unit/test_central/test_basic.py
+++ b/designate/tests/unit/test_central/test_basic.py
@@ -1267,7 +1267,6 @@ class CentralZoneTestCase(CentralBasic):
         self.service._is_valid_recordset_name = Mock()
         self.service._is_valid_recordset_placement = Mock()
         self.service._is_valid_recordset_placement_subzone = Mock()
-        self.service._is_valid_ttl = Mock()
         self.service._update_zone_in_storage = Mock()
         self.service._enforce_record_quota = mock.Mock()
 
@@ -1291,7 +1290,6 @@ class CentralZoneTestCase(CentralBasic):
             self.service._is_valid_recordset_placement_subzone.
             call_args[0][2]
         )
-        assert not self.service._is_valid_ttl.called
         assert not self.service._update_zone_in_storage.called
         assert self.service.storage.update_recordset.called
         assert self.service._enforce_record_quota.called
diff --git a/tests-py3.txt b/tests-py3.txt
index 224a32daa..ae902b737 100644
--- a/tests-py3.txt
+++ b/tests-py3.txt
@@ -1,4 +1,3 @@
 # Blacklist of tests failing on Python 3
-designate.tests.unit.test_central.test_basic
 designate.tests.unit.test_pool
 designate.tests.unit.test_producer.test_tasks