The city shall not be liable for any damage to a water service user by reason of stoppage or interruption of his or her water supply service caused by fires, scarcity of water, accidents to the water system or its mains, or which occurs as the result of maintenance and extension operations, or from any other unavoidable cause. This section shall not be construed to extend the liability of the city beyond that provided in the governmental immunity act. (1989 Code § 14-131)