Prior to beginning excavation, the contractor shall notify all utility companies of the location of the excavation work and request field location of their facilities. The contractor shall exercise care in excavating near all utilities or service connections to these utilities. They shall be protected, supported and maintained in service or restored to the condition in which they were found. Where such utilities cannot be replaced so as to occupy their original location, they shall be relocated by the respective utility company with the cooperation and assistance of the contractor. In the case of drain tile or sewers, the contractor shall relocate such facilities under the direction of the City. No excavation shall be made near any water main until Water Department personnel are on hand to shut off the main and authorize the contractor to proceed. The contractor shall not operate valves on existing water mains.