diff --git a/nixos/modules/services/databases/postgresql.nix b/nixos/modules/services/databases/postgresql.nix
index bae088c6610..06b9c3fbf4c 100644
--- a/nixos/modules/services/databases/postgresql.nix
+++ b/nixos/modules/services/databases/postgresql.nix
@@ -202,6 +202,8 @@ in
                   # For non-root operation.
                   initdb
                 fi
+                # See postStart!
+                touch "${cfg.dataDir}/.first_startup"
             fi
 
             ln -sfn "${configFile}" "${cfg.dataDir}/postgresql.conf"