diff --git a/services/hydra.nix b/services/hydra.nix
index 39604db..c06e2ef 100644
--- a/services/hydra.nix
+++ b/services/hydra.nix
@@ -62,5 +62,6 @@ in mkIf (elem "hydra" config.machine.services) {
       '';
     };
   };
+  systemd.services.nix-serve.serviceConfig.User = mkForce "hydra";
   systemd.services.nix-serve.environment.NIX_STORE_DIR = cacheDir;
 }