Which of these is the most accurate way to confirm the exact location of buried services?

Using trial holes is the most accurate way to confirm the exact location of buried services because it involves physically excavating the ground to directly visualize and identify the infrastructure present below the surface. This method allows for precise confirmation and eliminates the ambiguity that can arise from relying on indirect methods.

While utility maps can provide useful information about where services are likely to be, they are based on historical data and may not reflect the current situation accurately due to changes over time, such as new installations or alterations to existing services. Additionally, utility maps may not show all services, particularly if they are from different providers or have not been updated.

A metal detector can assist in locating certain types of buried services, primarily those that are metallic. However, it is not reliable for finding all types of services, especially non-metallic ones such as certain gas lines or plastic pipes.

Asking site workers may provide anecdotal information about the locations of buried services, but it is not a dependable method for verification. Workers may have varying levels of knowledge or may not be aware of all the utilities on site, leading to potential inaccuracies.

Thus, trial holes stand out as the most effective means for confirming the exact location of buried services, combining accuracy with a direct examination approach.