811 is a telephone number in Canada and the United States that is used for non-urgent health services in Canada and provides a uniform national phone number to access local utility location services in the United States. The number is used to call before digging to get underground utility lines marked for free and prevent undesired consequences. When you dial 811, your call is forwarded to the One Call Center in your area for processing. Local One Call Center operators record the location of the dig and then notify the affected utility companies of your digging plans. Your utility companies then dispatch a professional locating crew to mark the approximate location of your lines within a few days. Every dig requires a call to 811 to get your underground utility lines marked for free and prevent undesired consequences.