diff --git a/designate/quota/base.py b/designate/quota/base.py
index 1ac8c6e6e..23eb70848 100644
--- a/designate/quota/base.py
+++ b/designate/quota/base.py
@@ -66,7 +66,7 @@ class Quota(DriverPlugin):
 
         if resource not in quotas:
             raise exceptions.QuotaResourceUnknown("%s is not a valid quota "
-                                                  "resource", resource)
+                                                  "resource" % resource)
 
         return quotas[resource]
 
diff --git a/designate/quota/impl_storage.py b/designate/quota/impl_storage.py
index 54a9fb2e1..fb54de892 100644
--- a/designate/quota/impl_storage.py
+++ b/designate/quota/impl_storage.py
@@ -74,7 +74,7 @@ class StorageQuota(base.Quota):
         if resource not in list(six.iterkeys(
                self.get_default_quotas(context))):
             raise exceptions.QuotaResourceUnknown("%s is not a valid quota "
-                                                  "resource", resource)
+                                                  "resource" % resource)
 
         try:
             create_quota()