diff --git a/hooks/percona_utils.py b/hooks/percona_utils.py
index c21bc14..12a6bcc 100644
--- a/hooks/percona_utils.py
+++ b/hooks/percona_utils.py
@@ -1828,8 +1828,7 @@ def create_nagios_user():
         else:
             log("User 'nagios'@'localhost' already exists.", level="WARNING")
     # NOTE (rgildein): Update the user's password if it has changed.
-    m_helper.execute("ALTER USER 'nagios'@'localhost' IDENTIFIED BY "
-                     "'{passwd}';".format(passwd=nagios_password()))
+    m_helper.set_mysql_password('nagios', nagios_password())
 
 
 def set_nagios_user():
diff --git a/unit_tests/test_percona_utils.py b/unit_tests/test_percona_utils.py
index 9443150..6b95e92 100644
--- a/unit_tests/test_percona_utils.py
+++ b/unit_tests/test_percona_utils.py
@@ -539,11 +539,14 @@ class UtilsTests(CharmTestCase):
 
         mock_apt_update.assert_not_called()
 
+    @mock.patch.object(percona_utils, "lsb_release")
     @mock.patch.object(percona_utils, "get_db_helper")
     @mock.patch.object(percona_utils, "write_nagios_my_cnf")
     def test_create_nagios_user(self,
                                 mock_create_nagios_mysql_credential,
-                                mock_get_db_helper):
+                                mock_get_db_helper,
+                                mock_lsb_release):
+        mock_lsb_release.return_value = {'DISTRIB_CODENAME': 'bionic'}
         my_mock = mock.Mock()
         self.leader_get.return_value = "1234"
         self.is_leader.return_value = True
@@ -555,8 +558,8 @@ class UtilsTests(CharmTestCase):
         )
         my_mock.execute.assert_has_calls([
             mock.call("CREATE USER 'nagios'@'localhost';"),
-            mock.call("ALTER USER 'nagios'@'localhost' IDENTIFIED BY '1234';"),
         ])
+        my_mock.set_mysql_password.assert_called_once_with('nagios', '1234')
 
         class OperationalError(Exception):
             pass
@@ -566,7 +569,7 @@ class UtilsTests(CharmTestCase):
         def mysql_create_user(*args, **kwargs):
             raise OperationalError()
 
-        my_mock.select.return_value = True
+        my_mock.select.return_value = False
         my_mock.execute.side_effect = mysql_create_user
         with self.assertRaises(OperationalError):
             percona_utils.create_nagios_user()