diff --git a/synapse/notifier.py b/synapse/notifier.py
index 7121d659d0..b12b54353e 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -427,3 +427,6 @@ class Notifier(object):
 
         listeners = self.room_to_listeners.setdefault(room_id, set())
         listeners |= new_listeners
+
+        for l in new_listeners:
+            l.rooms.add(room_id)