diff --git a/lib.nix b/lib.nix
index 8703950..1aa8fcd 100644
--- a/lib.nix
+++ b/lib.nix
@@ -127,7 +127,7 @@ in
           echo
           echo "PostgreSQL is setting up the initial database"
           echo
-          pg_ctl -w start -o "-c unix_socket_directories=${data_dir} -c listen_addresses= -p ${builtins.toString port}"
+          pg_ctl -w start -o "-c unix_socket_directories=${runtimeDir} -c listen_addresses= -p ${builtins.toString port}"
           pg_ctl -m fast -w stop
         else 
           echo