diff --git a/apps/users/tests/test_forms.py b/apps/users/tests/test_forms.py
index 8c814848b..92332a1df 100644
--- a/apps/users/tests/test_forms.py
+++ b/apps/users/tests/test_forms.py
@@ -41,7 +41,8 @@ def test_duplicate_username(self):
         self.assertFalse(form.is_valid())
         self.assertIn("username", form.errors)
 
-    def test_duplicate_email(self):
+    def test_duplicate_email_does_not_report_the_address_is_taken(self):
+        """Enumeration prevention keeps signup from confirming a known address."""
         user = User.objects.create_user("test1", "test@example.com", "testpass")
         EmailAddress.objects.create(user=user, email="test@example.com")
 
@@ -54,8 +55,8 @@ def test_duplicate_email(self):
             }
         )
 
-        self.assertFalse(form.is_valid())
-        self.assertIn("email", form.errors)
+        self.assertTrue(form.is_valid())
+        self.assertNotIn("email", form.errors)
 
     def test_newline_in_username(self):
         # Note that since Django 1.9, forms.CharField().strip is True
diff --git a/apps/users/tests/test_views.py b/apps/users/tests/test_views.py
index 008802771..1c8109053 100644
--- a/apps/users/tests/test_views.py
+++ b/apps/users/tests/test_views.py
@@ -240,8 +240,22 @@ def test_user_duplicate_username_email(self):
         }
         self.assertUserCreated(data=post_data)
         response = self.assertUserCreated(data=post_data, template_name="account/signup.html")
+        # A taken username still has to be reported. A taken email must not be:
+        # enumeration prevention sends mail to the address instead.
         self.assertContains(response, "A user with that username already exists.")
-        self.assertContains(response, "A user is already registered with this email address.")
+        self.assertNotContains(response, "A user is already registered with this email address.")
+
+    def test_password_reset_does_not_reveal_whether_the_email_is_known(self):
+        """An unknown address gets the same page as a known one."""
+        url = reverse("account_reset_password")
+
+        known = self.client.post(url, {"email": self.user.email}, follow=True)
+        unknown = self.client.post(url, {"email": "nobody@example.com"}, follow=True)
+
+        self.assertEqual(known.status_code, 200)
+        self.assertEqual(unknown.status_code, 200)
+        self.assertEqual(known.redirect_chain, unknown.redirect_chain)
+        self.assertNotContains(unknown, "The email address is not assigned to any user account")
 
     def test_usernames(self):
         url = reverse("account_signup")
diff --git a/pydotorg/settings/base.py b/pydotorg/settings/base.py
index 0253506b7..711b4cd63 100644
--- a/pydotorg/settings/base.py
+++ b/pydotorg/settings/base.py
@@ -101,8 +101,7 @@
 ACCOUNT_SIGNUP_FIELDS = ["email*", "username*", "password1*", "password2*"]
 ACCOUNT_UNIQUE_EMAIL = True
 ACCOUNT_EMAIL_VERIFICATION = "mandatory"
-# TODO: Enable enumeration prevention
-ACCOUNT_PREVENT_ENUMERATION = False
+ACCOUNT_PREVENT_ENUMERATION = True
 SOCIALACCOUNT_EMAIL_REQUIRED = True
 SOCIALACCOUNT_EMAIL_VERIFICATION = True
 SOCIALACCOUNT_QUERY_EMAIL = True