diff --git a/tesla-mate-container.nix b/tesla-mate-container.nix
index 0f52100..12b8b4f 100644
--- a/tesla-mate-container.nix
+++ b/tesla-mate-container.nix
@@ -93,6 +93,11 @@ in {
           "Password with which to authenticate with the MQTT server.";
       };
     };
+
+    state-directory = mkOption {
+      type = str;
+      description = "Path at which to store service state.";
+    };
   };
 
   config = mkIf cfg.enable {