diff --git a/queries.yaml b/queries.yaml
index 24abb9a9..800e62bd 100644
--- a/queries.yaml
+++ b/queries.yaml
@@ -1,5 +1,5 @@
 pg_replication:
-  query: "SELECT EXTRACT(EPOCH FROM (now() - pg_last_xact_replay_timestamp())) as lag"
+  query: "SELECT CASE WHEN NOT pg_is_in_recovery() THEN 0 ELSE GREATEST (0, EXTRACT(EPOCH FROM (now() - pg_last_xact_replay_timestamp()))) END AS lag"
   master: true
   metrics:
     - lag: