diff --git a/nixos/modules/notnft.nix b/nixos/modules/notnft.nix
index 1eb04e8..06dd260 100644
--- a/nixos/modules/notnft.nix
+++ b/nixos/modules/notnft.nix
@@ -10,7 +10,8 @@ let
     optionalAttrs
     listToAttrs
     optional
-    filter;
+    filter
+    optionalString;
   cfg = config.networking.notnft;
   jsonFormat = (pkgs.formats.json {});
 in
@@ -115,7 +116,7 @@ in
         RemainAfterExit = true;
         ExecStart = startScript;
         ExecReload = startScript;
-        ExecStop = "${pkgs.nftables}/bin/nft flush ruleset";
+        ExecStop = optionalString cfg.flush "${pkgs.nftables}/bin/nft flush ruleset";
       };
     };
   };