diff --git a/third_party/repo.bzl b/third_party/repo.bzl
index 965d51d3a41..38a8805f31c 100644
--- a/third_party/repo.bzl
+++ b/third_party/repo.bzl
@@ -34,14 +34,6 @@ def _get_link_dict(ctx, link_files, build_file):
     return {ctx.path(v): Label(k) for k, v in link_files.items()}
 
 def _tf_http_archive_impl(ctx):
-    # if len(ctx.attr.urls) < 2 or "mirror.tensorflow.org" not in ctx.attr.urls[0]:
-    if False:  # TODO(b/174771515): fix call sites and enable check again.
-        fail("tf_http_archive(urls) must have redundant URLs. The " +
-             "mirror.tensorflow.org URL must be present and it must come first. " +
-             "Even if you don't have permission to mirror the file, please " +
-             "put the correctly formatted mirror URL there anyway, because " +
-             "someone will come along shortly thereafter and mirror the file.")
-
     # Construct all labels early on to prevent rule restart. We want the
     # attributes to be strings instead of labels because they refer to files
     # in the TensorFlow repository, not files in repos depending on TensorFlow.
@@ -98,6 +90,20 @@ def tf_http_archive(name, sha256, urls, **kwargs):
     labels (e.g. '@foo//:bar') or from a label created in their repository (e.g.
     'str(Label("//:bar"))').
     """
+    if len(urls) < 2:
+        fail("tf_http_archive(urls) must have redundant URLs.")
+
+    if not any([mirror in urls[0] for mirror in (
+        "mirror.tensorflow.org",
+        "mirror.bazel.build",
+        "storage.googleapis.com",
+    )]):
+        fail("The first entry of tf_http_archive(urls) must be a mirror " +
+             "URL, preferrably mirror.tensorflow.org. Even if you don't have " +
+             "permission to mirror the file, please put the correctly " +
+             "formatted mirror URL there anyway, because someone will come " +
+             "along shortly thereafter and mirror the file.")
+
     if native.existing_rule(name):
         print("\n\033[1;33mWarning:\033[0m skipping import of repository '" +
               name + "' because it already exists.\n")