Subsurface Utility Quality Level Checklist
Checks subsurface utility locating against AS5488 quality levels QL-A to QL-D and methods.
Checklist
Record the subsurface utility information quality level (QL-D to QL-A) for a located service. Follow AS 5488 and your project's requirements.
Still outstanding
- QL-D — existing records only
- QL-C — records reconciled to surface features
- QL-B — detected with geophysics (EML / GPR)
- QL-A — exposed and measured (potholing)
- Method and equipment recorded
- Horizontal position captured
- Depth captured (and to what — top/centre)
- Surface features tied in
- Utility type, size and material
- QL labelled per utility on the plan
- Confidence / limitations noted
A field and study aid only — follow your organisation's procedures, project brief and QA requirements. Nothing here is stored.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Tick the quality level achieved (QL-D to QL-A) and the evidence captured for each located utility.
- Track completeness and the outstanding list.
- Record the QL per utility on the plan, with any limitations.
How it works
AS 5488 grades subsurface utility information by quality level: QL-D (records only), QL-C (records reconciled to surface features), QL-B (geophysically detected) and QL-A (exposed and measured). The QL tells everyone how reliable each located service is.
This is a browser-only recording aid — follow AS 5488 and your project's requirements for what each level demands.
Worked example
A water main located with GPR. Detected with ground-penetrating radar (QL-B), horizontal position and approximate depth captured, tied to surface features, and labelled QL-B with its limitations on the plan.
Frequently asked questions
What's the difference between QL-B and QL-A?
QL-B is detected from the surface with geophysics (position good, depth approximate). QL-A is the utility physically exposed (potholed) and measured — the highest confidence in both position and depth.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
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Cite this tool
Zerdly. (2026). Subsurface Utility Quality Level Checklist. Retrieved from https://www.zerdly.com/tools/subsurface-utility-quality-level-checklist/
Tip: Enter any known values to calculate the remaining results.
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