"Level B" of data focuses on horizontally designating underground utilities on the ground surface using paint or flags—such as markings provided through an 811 request or by a private locating company like Gateway. Electronic utility detection equipment is used to identify the utility locations, which are then marked on the surface. While this information can be quite accurate, it remains approximate and generally does not include depth data. The results are combined with information from Quality Levels D and C, and the designated utilities are surveyed and incorporated into the drawings, representing the outcome of a Quality Level B investigation.

"Level C" of data involves surveying visible utility features such as manholes, catch basins, valves, fire hydrants, and gas risers—or verifying the accuracy of existing survey data if they have already been mapped. The information gathered is combined with Quality Level D data, and both levels are clearly labeled. It’s common for Quality Level C data to reveal discrepancies with Quality Level D information, prompting further investigation into the true locations of certain underground utility lines.

"Level D" of data is developed by collecting information from existing records such as architectural and “as-built” drawings, utility maps, photographs, survey files, and even interviews with individuals familiar with the site. While useful, this information is often limited and may not provide a full or accurate representation of current site conditions. Some sources may be outdated, incomplete, or unreliable—memories fade, old plans may not reflect modifications, and “as-builts” may not show the true utility routes. Once gathered, the information is compiled into drawings that clearly indicate the corresponding quality level.