Risk Is Not a Score
In sewer management, one mistake quietly drives millions in misallocated capital:
We confuse condition scores with risk.
They are not the same.
A pipe with a moderate PACP score can be your highest-risk asset.
A pipe with severe defects might pose minimal operational threat.
If you rank projects based on “worst condition first,” you are not managing risk.
You are managing visibility.
Condition vs. Risk (Clear Distinction)
Let’s simplify it.
Condition = Physical state of the asset
Risk = Likelihood × Consequence × Timing
CCTV tells you what the pipe looks like.
Risk tells you what happens if it fails and when.
A cracked 8-inch pipe in a low-impact easement is not the same as a moderate defect pipe under a major roadway near a school or waterway.
One is structurally worse.
The other is operationally dangerous.
Why “Worst First” Often Fails
Many utilities default to:
“Rehabilitate the highest PACP scores first.”
It sounds logical. It’s measurable. It’s defendable.
But it ignores three critical factors:
Is the pipe actually failing?
What happens if it fails?
How soon is failure likely?
The result?
Capital dollars chase high scores while repeat blockages, backups, and public exposure continue elsewhere.
What Risk Actually Looks Like in Practice
In a large active collection system, several pipes had severe structural scores from CCTV. They looked bad. On paper, they were top priority.
But when overlaid with:
Historical work orders
Backup frequency
Proximity to sensitive receptors
Traffic impact
Some of those high-score pipes dropped down the priority list.
At the same time, moderate condition pipes with recurring blockages and high consequence moved up.
Those pipes were not the “worst.”
They were the most dangerous to ignore.
That’s risk thinking.
Consequence Is the Multiplier
Condition tells you likelihood.
Consequence determines impact.
High consequence can mean:
Repeated basement backups
Environmental discharge risk
Major traffic disruption
Regulatory exposure
Political visibility
Without consequence layered in, condition scores are incomplete.
Timing Changes Everything
A pipe likely to fail in 10 years is not the same as one trending toward failure next winter.
Seasonality.
Groundwater levels.
Root intrusion cycles.
Maintenance history.
Risk is dynamic not static.
And most ranking lists treat it as frozen in time.
A Better Way to Think About It
Before ranking projects, ask:
What is the likelihood of failure?
What is the consequence if it fails?
When is that failure most probable?
Even a simple Low / Medium / High classification layered onto condition data dramatically improves decision clarity.
No new software required.
Just structured thinking.
Why This Matters
When utilities separate condition from risk:
CIP planning becomes defensible
O&M becomes targeted
Field crews understand why priorities shift
Leadership sees logic, not just scores
And most importantly:
Resources go where impact is highest.
Next Issue
Condition tells you how bad it looks.
Risk tells you how bad it could get.
In Issue #4, we will go deeper into the most misunderstood variable in sewer management:
Consequence and why it’s the multiplier most utilities underestimate.