Whether you are an excavating contractor installing pipelines or a homeowner putting in a backyard spa, call Underground Service Alert of Southern California, 1-800-227-2600opens phone dialer, or dial 811opens phone dialer, at least two working days in advance. Otay and other utility companies with facilities in the area will respond by marking the location of the underground lines they are responsible for maintaining. There is no charge for this service. See opens in a new windowhttp://www.digalert.org/.