Quality Level D
Level D — Records & Information
Existing records, as-builts, and verbal data. The starting point — useful for planning, never trusted alone.
When to use it: Early feasibility, alignment studies, scoping budgets.
Engineering Reference
SUE Levels A–D: A practical guide to Subsurface Utility Engineering.
Subsurface Utility Engineering is the discipline of finding what's underground before you design or dig. The ASCE 38-22 standard defines four quality levels — here is what each one actually means, and when to require it.
Why SUE Matters
Underground risk is the single largest source of schedule and cost surprise on infrastructure projects.
Every utility strike, redesign, or change order on an infrastructure project starts with one of two things: bad data, or no data. SUE replaces guesswork with engineered, signed information about the utilities already in the ground.
ASCE 38-22 is the American Society of Civil Engineers' standard for classifying that data into four utility quality levels — D, C, B, and A — from lowest to highest reliability. Specifying the right level in the design contract is how owners control underground risk before the first crew mobilizes.
CSL Consults LLC, an MBE/DBE-certified engineering firm (Texas Firm No. F-29543), specifies and oversees SUE on utility, fiber, telecom, and data center programs across Texas, Arizona, and New Mexico.
ASCE 38-22
The four SUE quality levels, explained.
Quality Level C
Level C — Surface Visible Evidence
A surface survey of visible appurtenances (manholes, valves, pedestals, markers) correlated to Level D records.
When to use it: Conceptual design and corridor planning where buried utilities are not yet a design driver.
Quality Level B
Level B — Designating
Geophysical locating — electromagnetic induction and ground penetrating radar (GPR) — to horizontally place utilities on the design plan with two-dimensional accuracy.
When to use it: 30%–60% design, route engineering, fiber and conduit alignment, HDD corridor screening.
Quality Level A
Level A — Locating
Vacuum-excavated test holes expose the utility. Size, material, condition, horizontal position, and depth are measured directly and tied to survey control.
When to use it: Final design, HDD entry/exit and bore profile validation, conflict resolution, critical tie-ins, and high-consequence crossings.
Specifying SUE
How to write SUE into a project, the right way.
Most projects do not need Level A on every utility — that would be expensive and unnecessary. The discipline is matching the level to the risk on each segment of the work.
- Start with D + C across the whole corridor to scope the problem.
- Escalate to B on the design alignment and any congested zones.
- Require A at HDD bore profiles, deep crossings, critical tie-ins, and identified conflicts.
- Sign and seal the SUE deliverables with a licensed professional engineer, with utility quality levels labeled on every drawing.
A Texas-licensed PE on the CSL team reviews every SUE scope, deliverable, and conflict matrix before it goes to construction.
Need SUE specified on your next project?
We'll scope the right mix of Levels D, C, B, and A for your corridor — and stand behind it with a PE-stamped deliverable.