Sec. 753-4.10. Unverifiable underground facilities

If an excavator notifies an operator that, after diligent search at a reasonable depth within the tolerance zone as staked, marked or otherwise designated by the operator, that he or she cannot verify the location of an underground facility, the operator shall verify such location as soon as possible or shall provide the excavator with prompt field assistance or use other means mutually agreed to by the excavator and operator. Such agreement shall be provided to the excavator upon his or her request.