Anonymised QRBS case study • Brisbane

When an underground sewer survey does not fully answer the certifier's RFI.

A private certifier required an accurate diagram showing an as-constructed dwelling's proximity to the sewer main and house connection branch. The first survey produced useful information, but it did not completely resolve the evidence requirement.

Sewer main locatedHouse connection unresolvedBuild Over Asset pathway triggered

The actual requirement

The certifier did not ask for a general underground-services scan.

The information request required a pipe survey and accurate diagram showing the dwelling's proximity to both the sewer main and the house connection branch. The evidence was needed to assess whether the existing building affected the infrastructure and whether a separate asset-owner approval was required.

A report can contain useful locating information but still leave an RFI unanswered if one required branch, connection point or relationship to the building is not verified.

Evidence requested

Every part of the certifier's requirement had to be addressed.

Pipe survey

A specialist survey of the relevant underground sewer infrastructure

Accurate diagram

A usable drawing rather than a general description of the service location

Sewer main

The main pipe location, depth and proximity to the dwelling

House connection

The branch connecting the property to the sewer main

Building relationship

Offsets showing how both sewer elements relate to the as-constructed work

Verification

A clear statement of accuracy, access limits and any further work needed

Why assumptions are risky

Buried pipes cannot be reliably assessed by looking at the ground or assuming where they should run.

Authority drawings and Before You Dig Australia information are important starting points, but they may be indicative rather than a precise record of what was installed. Construction changes, undocumented connections and incomplete historical records can all affect the true location.

This creates a material risk of building too close to infrastructure or damaging a pipe during excavation, footing work or remediation. Specialist locating and, where required, positive physical verification are therefore important before relying on underground service positions.

What the first survey achieved

The report was useful, but it did not complete the required evidence package.

The specialist consultant located the sewer main, recorded depths and offsets and produced an underground-utility map. The findings also indicated that a sewer connection feature was immediately beside part of the ground-floor building.

That proximity exposed a separate Build Over Asset approval pathway. The survey therefore added important information even though it did not fully answer the certifier's original request.

A separate infrastructure pathway

Locating the pipes can reveal another approval requirement.

Because part of the building was extremely close to the sewer connection, a separate Build Over Asset application to the infrastructure owner was required. Engineering information may be needed to address nearby footings, loading, protection of the sewer and access for future maintenance.

This infrastructure assessment is separate from council planning and from the private certifier's building assessment. Obtaining one approval does not automatically satisfy the others.

How QRBS addresses the risk

The service connects the certifier's exact requirement with a defined consultant deliverable.

QRBS does more than provide a consultant's contact details. The objective is to define the evidence required, manage access and contingency issues and coordinate a report that can be used in the next approval step.

The property owner remains free to select the consultant. The locator is responsible for its own methods and findings, and the private certifier decides whether the evidence satisfies the building application.

The verified position

This remains an ongoing approval matter.

The survey located the sewer main and helped identify the need for a Build Over Asset application. The house connection branch was not fully traced, further specialist investigation may be required and engineering information was expected for the infrastructure pathway.

No claim is made that the RFI has been satisfied, the building application approved or a final certificate issued.

The practical lesson

The objective is not merely to obtain a report—it is to obtain evidence that answers the RFI.

Define the deliverable and the contingency before the site visit

Confirm which pipes must be located, the required accuracy, the access points needed, the alternative method if access fails, the drawing and report formats and who will check the finished evidence against the certifier's request.

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Every site, underground-service condition and approval pathway is different. Specialist consultants exercise independent professional judgement, and the relevant infrastructure owner, council and private certifier make their respective decisions. Previous project experience does not guarantee approval in another matter.