diff --git a/nixos/modules/services/backup/postgresql-backup.nix b/nixos/modules/services/backup/postgresql-backup.nix
index 4a5ebebc682e1..978eeccd3573b 100644
--- a/nixos/modules/services/backup/postgresql-backup.nix
+++ b/nixos/modules/services/backup/postgresql-backup.nix
@@ -9,7 +9,7 @@ let
 
   postgresqlBackupCron = db:
     ''
-      ${config.services.postgresqlBackup.period} root ${config.services.postgresql.package}/bin/pg_dump ${db} | ${gzip}/bin/gzip -c > ${location}/${db}.gz
+      ${config.services.postgresqlBackup.period} root ${config.services.postgresql.package}/bin/pg_dump ${db} -U postgres | ${gzip}/bin/gzip -c > ${location}/${db}.gz
     '';
 
 in