diff --git a/nixos/modules/services/misc/svnserve.nix b/nixos/modules/services/misc/svnserve.nix
index f70e3ca7fef..5fa262ca3b9 100644
--- a/nixos/modules/services/misc/svnserve.nix
+++ b/nixos/modules/services/misc/svnserve.nix
@@ -24,6 +24,7 @@ in
       };
 
       svnBaseDir = mkOption {
+        type = types.str;
         default = "/repos";
         description = "Base directory from which Subversion repositories are accessed.";
       };