diff --git a/docs/contributing.txt b/docs/contributing.txt
index e58b06881ab..0e8dff68f4c 100644
--- a/docs/contributing.txt
+++ b/docs/contributing.txt
@@ -532,8 +532,8 @@ Yes, the unit tests need a settings module, but only for database connection
 info -- the ``DATABASE_NAME`` (required, but will be ignored),
 ``DATABASE_ENGINE``, ``DATABASE_USER`` and ``DATABASE_PASSWORD`` settings. You
 will also need a ``ROOT_URLCONF`` setting (its value is ignored; it just needs
-to be present) and a ``SITE_ID`` setting (any integer value will do) in order
-for all the tests to pass.
+to be present) and a ``SITE_ID`` setting (any non-zero integer value will do)
+in order for all the tests to pass.
 
 The unit tests will not touch your existing databases; they create a new
 database, called ``django_test_db``, which is deleted when the tests are