Most councils have a condition grading scale. Far fewer use it consistently — or understand what each grade should actually trigger.
The IIMM scale runs from C1 (very good) to C5 (very poor/failed). On paper, five grades. In practice, the decision-making value depends entirely on how those grades are defined, applied, and acted on.
Here's what each grade should mean in plain terms — and what it should trigger.
C1 — New
Asset is new or as-new. Performing as intended. No intervention required.
C2 — Good
Minor wear or defects. Still well within service life. Preventive maintenance may apply, but no renewal trigger yet.
C3 — Satisfactory
The asset is still functional, but this is the threshold NSW councils should formally define as the minimum acceptable condition. At C3, the asset should be entering the planning process for renewal or upgrade — not waiting until condition deteriorates further.
C4 — Poor
Renewal required. The asset is no longer meeting its required service level and needs to be included in the short-term works program. Any asset at C4 or below contributes directly to the infrastructure backlog.
C5 — Very Poor / Failed
Reconstruction required. The asset has reached end of service life or poses a safety risk. Emergency intervention is likely. If action wasn't taken at C4, the cost of getting here is substantially higher.
The five-grade scale is deliberately simple — and that's the point. It doesn't require engineering qualifications to apply in the field. A maintenance officer, an inspector, or a council asset team can grade assets consistently using plain descriptors.
For large councils managing tens of thousands of assets across multiple classes, the scale enables portfolio-level analysis — identifying where the bulk of C4 and C5 assets sit, modelling renewal expenditure by asset class, and prioritising the program. For smaller councils with limited staff and tighter budgets, it provides the same decision framework at a proportionate scale. A council with 500 road segments and a council with 50,000 road segments are applying the same logic: C3 triggers planning, C4 triggers renewal, C5 triggers reconstruction. The decision thresholds don't change with council size. What changes is the volume of data — not the framework.
The satisfactory condition threshold matters beyond individual asset decisions. The infrastructure backlog — a key metric in council financial sustainability assessments — is calculated as the cost to bring all assets below satisfactory condition back to that standard. If C3 isn't formally defined as satisfactory in your AMP, your backlog figure is unreliable.