From the Indiana Office of Utility Consumer Counselor:
Did you know Indiana law requires you to have your yard marked for underground utility lines before you can put in a mailbox, build a fence, or plant a tree? April is Safe Digging Month across the United States, an important annual reminder as the weather starts to warm up.
Even small digging projects require utility markings because underground lines are often shallower than you’d expect.
Contact Indiana 811 at least two business days before digging. There is no charge to have your lines marked and the 8-1-1 call center is open around the clock, seven days a week. You can also complete the form at Indiana811.org. Markings are effective for 20 days.