Utility companies who respond to locate request, via the state One-Call system will only locate and mark facilities that they own. They will not mark privately owned facilities that are owned by a consumer.
Common examples of these facilities are electric, gas, and water services after the point in which the product is metered. Many industrial complexes have privately owned communication systems between main buildings and out lying buildings. By locating these facilities you can avoid large repair bills and unproductive down time that can run up job costs.