diff --git a/modules/system/boot/systemd-unit-options.nix b/modules/system/boot/systemd-unit-options.nix
index fd4d19d1dd05..e3542ce9225a 100644
--- a/modules/system/boot/systemd-unit-options.nix
+++ b/modules/system/boot/systemd-unit-options.nix
@@ -145,6 +145,16 @@ rec {
         <citerefentry><refentrytitle>systemd.service</refentrytitle>
         <manvolnum>5</manvolnum></citerefentry> for details.
       '';
+
+      check = v:
+        let assertValueOneOf = name: values: attr:
+              let val = getAttr name attr;
+              in optional ( hasAttr name attr && !elem val values) "${name} ${val} not known to systemd";
+            checkType = assertValueOneOf "Type" ["simple" "forking" "oneshot" "dbus" "notify" "idle"];
+            checkRestart = assertValueOneOf "Restart" ["no" "on-success" "on-failure" "on-abort" "always"];
+            errors = concatMap (c: c v) [checkType checkRestart];
+        in if errors == [] then true
+           else builtins.trace (concatStringsSep "\n" errors) false;
     };
 
     script = mkOption {