The recent issue of Damage Prevention Professional Magazine shows photos which point out the need to watch out for buried utility lines hear the surface. While damages which occur in such instances are often blamed on construction contractors who are digging, there's much to suggest that when such damages take place, utility companies and the firms they contract to install underground lines may bear some of the blame.
While all but three states require marks to be within 18 to 24 inches of the actual underground location of buried lines and pipes, not every state's laws speak to the matter of depth of lines. However, a number of states do provide guidance on the matter, as does a federal study, suggesting that it's recognized that lines should be buried deep enough to ensure that light digging or scraping doesn't hit them.