ASCE 38 organizes utility information into four quality levels: QL-D, QL-C, QL-B, and QL-A. Each level reflects how utility data was gathered and how much confidence a project team can place in that information.

QL-D: Records Information

Records research is the starting point for most utility investigations. It helps establish context, but record-based information is often incomplete, outdated, or inconsistent. It’s useful to assist in field data collection and to fill in the blanks for utilities that are identified on records but cannot be identified in the field using the methods prescribed in the investigation scope. At 4Sight we use QL-D to give crews an initial idea of what utilities will be present, fill in information gaps, and plan where additional field investigation may be needed.

QL-C: Surface Feature Correlation

Quality Level C adds field context by correlating visible above-ground utility features with available utility records. It improves the usefulness and certainty of record information for utility segments that can be further refined using surface features. We use QL-C mostly for sewer segments where inverts can be collected at upstream and downstream chambers then tied together with records information. We may also use it for water or gas where valves may be visible, but we are unable to obtain a QL-B signal.  This helps to improve certainty of data and improve the reliability of the overall utility picture.

QL-B: Geophysical Designation

For many projects, this is the desired quality level to be achieved for most utilities’ alignments present in key areas of the project. Using the geophysical designating process also allows field technicians to identify utilities that may not appear on records and otherwise would not have been shown on drawings. QL-B often provides the level of utility information needed for meaningful design progress, but it may still leave unanswered questions about depth or exact utility position in high-risk areas. 4Sight applies geophysical designation to move projects beyond assumption-based mapping and toward field-supported utility intelligence that designers can use with more confidence.

QL-A: Test Holes and Vacuum Excavation

Quality Level A is the highest-confidence level of utility investigation. It is not necessarily required everywhere. Its value comes from targeted verification in places where uncertainty carries the greatest impact. We install test holes at key locations to accurately capture utility depth, alignment, material, and size. Using QL-A strategically, we target and expose critical utilities, significantly reducing uncertainty and improving project confidence.

How We Deliver ASCE 38 Utility Investigations

ASCE 38 is most effective when it is treated as a coordinated investigation process, not a checklist item. Our approach is built around project risk, site conditions, and the quality of information needed to support real design decisions.