Your local utilities office should perform this free of charge. If you live in the usa, you must make an 811 " digline " call and set up a time to have your property inspected to determine the location of underground utility pipes and cables before starting any digging project.
[header] How to build a retaining wall [title] Plan and layout the site. [step] Plan where your retaining wall is going to be using stakes and string, leveling off to ensure an even height and using a tape measure to ensure an even length. [substeps] Contact your local utilities office to confirm that there are no pipes or cables in your digging zone.