The PA One Call System helps prevent the accidental digging into dangerous lines. Not less than 3 or more than 10 working days before you dig call 1-800-242-1776 (PA1CALL) and use white marks to outline the location, route or boundary of proposed excavation. IT IS THE LAW! As a member of HBAA you receive this service for free. If you ever get a bill from the PA1CALL, fax it or mail it to us at HBAA.