diff --git a/queries.yaml b/queries.yaml
new file mode 100644
index 00000000..9db5e077
--- /dev/null
+++ b/queries.yaml
@@ -0,0 +1,6 @@
+pg_replication:
+  query: 'SELECT EXTRACT(EPOCH FROM (now() - pg_last_xact_replay_timestamp()))::INT as lag'
+  metrics:
+    - lag:
+        usage: 'GAUGE'
+        description: 'Replication lag behind master in seconds'