diff --git a/data/event-schemas/schema/m.room.power_levels.yaml b/data/event-schemas/schema/m.room.power_levels.yaml
index a24b2e44..3beed1d8 100644
--- a/data/event-schemas/schema/m.room.power_levels.yaml
+++ b/data/event-schemas/schema/m.room.power_levels.yaml
@@ -75,6 +75,9 @@ properties:
         description: |-
             The default level required to send state events. Can be overridden
             by the `events` key. Defaults to 50 if unspecified.
+
+            **Note**: When there is no power levels event in the room, this defaults
+            to 0. See description for more information.
         type: integer
       users:
         additionalProperties: