02 · Audit & Condition Assessment

We don't guess a GPT's condition. We rate it, cost it, and prioritise it.

A worked example: the City of Canterbury Bankstown engaged Renew to audit and condition-assess its entire Gross Pollutant Trap portfolio — establishing a defensible baseline for maintenance and capital planning. This is the same rigour we'd bring to Greater Geelong.

GPT assets audited & condition-assessed (of 99 allocated)

2.2

average condition rating — portfolio structurally serviceable

55/45

proprietary vs non-proprietary device split

5 mo

audit period, June–October 2025

CLIENT · CITY OF CANTERBURY BANKSTOWNREF · RSN24250ASSET IDS · WQD00001–WQD03012

Executive summary — key finding

"Most defects related to maintenance execution, access limitations and serviceability — not structural failure. Elevated condition ratings were often driven by incomplete or inconsistent cleaning."

In plain terms: the assets were mostly sound, but the maintenance standard was letting them down. Better methodologies, access and reporting — not wholesale capital replacement — were shown to reduce risk and extend asset life. That's precisely the gap a RenewQEST program closes.

Audit methodology

Four stages, every asset, same standard.

Desktop assessment

Existing data, spatial information and historical records reviewed before site works.

Field audit

Make, model and type verified on site and standardised against manufacturer data.

Condition assessment

Structural integrity, serviceability, access and performance rated per Council's RFQ criteria.

Quantity & quality modelling

Rational Method peak-flow (ARR 2019) and MUSIC pollutant-load modelling per catchment.

Portfolio composition

A mixed fleet — verified and standardised.

97 assets reviewed against historical council data and manufacturer information to standardise make, model and type across the register.

Proprietary units (55%)

Non-proprietary units (45%)

Distribution by model type

Trash racks / sediment basins28

CDS units13

Ecosol9

Humegard9

Debris booms9

Cleansall8

Humeceptor7

Bandalong4

Risk-based prioritisation

Every defect ranked on a likelihood-vs-consequence matrix.

Consistent with Council's RFQ framework, so resources are directed to the highest-risk assets first — cost-effective maintenance and capital planning, evidenced.

Priority 1

Highest priority

High risk of failure — immediate intervention.

Priority 2

High priority

Moderate risk — affects asset functionality.

Priority 3

Medium priority

Life-cycle maintenance / renewal work.

Priority 4

Low priority

Low risk — monitor at scheduled intervals.

The deliverable

One standardised Asset Data Sheet — for every asset.

Audited data, condition outcomes, catchment modelling, inspection & cleaning instructions and photographs, in one consistent format. Below is the standardised layout Council receives per GPT.

ASSET DATA SHEET

SAMPLE · STANDARDISED FORMAT

ASSET ID · WQD00001

CDS Unit — Model CDS3018

Proprietary Gross Pollutant Trap · Continuous Deflection Separation

Condition rating

2 — Good

Primary asset data

Manufacturer	CDS / Optimal
Type	Proprietary GPT
Treatable flow	Screened, hydrodynamic
Access	Confined-space entry
Sump capacity	550 mm sediment obs.

Catchment modelling

Method	Rational (ARR 2019)
Quality model	MUSIC
Catchment	Delineated & mapped

Condition & recommendations

Structure serviceable, no failure observed

Sediment build-up — schedule clean

Access cover surround — minor repair (P3)

Site photographs

Inspection & cleaning instructions attached per asset. Data GIS-exportable via Assetlogue.

Open the full Bankstown data-sheet report (PDF) Representative layout shown; illustrative values.

What this means for Greater Geelong

A single audit gives Council a defensible baseline — verified asset register, condition ratings, prioritised defects and cost estimates — before a dollar is spent on maintenance. That is the transparency the current standard isn't delivering.

See how we execute the works →