diff --git a/etc/matrix-synapse/conf.d/rooms.yaml b/etc/matrix-synapse/conf.d/rooms.yaml
new file mode 100644
index 0000000..6bbd465
--- /dev/null
+++ b/etc/matrix-synapse/conf.d/rooms.yaml
@@ -0,0 +1 @@
+forget_rooms_on_leave: true