diff --git a/doc/source/configuration/configuring.rst b/doc/source/configuration/configuring.rst
index 636650eda..8e20608c9 100644
--- a/doc/source/configuration/configuring.rst
+++ b/doc/source/configuration/configuring.rst
@@ -429,20 +429,38 @@ Configure Cinder Notifications
 
 Watcher can also consume notifications generated by the Cinder services, in
 order to build or update, in real time, its cluster data model related to
-storage resources. To do so, you have to update the Cinder configuration
-file on controller and volume nodes, in order to let Watcher receive Cinder
-notifications in a dedicated ``watcher_notifications`` channel.
+storage resources.
 
-  * In the file ``/etc/cinder/cinder.conf``, update the section
-    ``[oslo_messaging_notifications]``, by redefining the list of topics
-    into which Cinder services will publish events ::
+Cinder emits notifications on the ``notifications`` topic, in the openstack
+control exchange (as it can be seen in the `Cinder conf`_).
+
+  * In the file ``/etc/cinder/cinder.conf``, the value of driver in the section
+    ``[oslo_messaging_notifications]`` can't be noop.
 
       [oslo_messaging_notifications]
       driver = messagingv2
-      topics = notifications,watcher_notifications
 
-  * Restart the Cinder services.
+.. _`Cinder conf`: https://docs.openstack.org/cinder/latest/configuration/block-storage/samples/cinder.conf.html
 
+Configure Watcher listening to the Notifications
+================================================
+
+To consume either Cinder or Nova notifications, (or both), Watcher must be
+configured to listen to the notifications topics that Cinder and Nova emit.
+
+Use the `notification_topics`_ config option to indicate to Watcher that it
+should listen to the correct topics. By default, Cinder emits notifications
+on ``openstack.notifications``, while Nova emits notifications on
+``nova.versioned_notifications``. The Watcher conf should have the topics for
+the desired notifications, below is an example for both Cinder and Nova::
+
+    [watcher_decision_engine]
+
+    ...
+
+    notification_topics = nova.versioned_notifications,openstack.notifications
+
+.. _`notification_topics`: https://docs.openstack.org/watcher/latest/configuration/watcher.html#watcher_decision_engine.notification_topics
 
 Workers
 =======
diff --git a/releasenotes/notes/update-notification-topics-daf6303a63963ee9.yaml b/releasenotes/notes/update-notification-topics-daf6303a63963ee9.yaml
new file mode 100644
index 000000000..82a045724
--- /dev/null
+++ b/releasenotes/notes/update-notification-topics-daf6303a63963ee9.yaml
@@ -0,0 +1,7 @@
+---
+upgrade:
+  - |
+    Watcher now listens by default to the exchange and channel used by default
+    in Cinder, which is 'openstack.notifications'. The previous instructions
+    in the documentation to enable cinder notifications have been modified to
+    make clear that there is no need of changing the cinder conf.
diff --git a/watcher/conf/decision_engine.py b/watcher/conf/decision_engine.py
index 770924bee..b48f5750f 100644
--- a/watcher/conf/decision_engine.py
+++ b/watcher/conf/decision_engine.py
@@ -31,7 +31,8 @@ WATCHER_DECISION_ENGINE_OPTS = [
                     'used for RPC calls'),
     cfg.ListOpt('notification_topics',
                 default=['nova.versioned_notifications',
-                         'watcher.watcher_notifications'],
+                         'watcher.watcher_notifications',
+                         'openstack.notifications'],
                 help='The exchange and topic names from which '
                      'notification events will be listened to. '
                      'The exchange should be specified to get '