ISO/TR 24589-2:2025

Technical
Report
ISO/TR 24589-2
First edition
Examples of good practice for the
2025-05
management of assets of water
supply and wastewater systems —
Part 2:
Wastewater systems
Exemples de bonnes pratiques de la gestion d’actifs de systèmes
d'approvisionnement en eau potable et d'assainissement —
Partie 2: Systèmes d’eaux usées
Reference number
© ISO 2025
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ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principal aspects . 1
4.1 Objectives .1
4.1.1 Multiple wastewater utilities .1
4.1.2 Collection network .2
4.1.3 Treatment plants and other elements .2
4.2 Strategies .6
4.2.1 Maintenance strategy .6
4.2.2 Renewals decision .7
4.2.3 Inspection strategy of collection network .7
5 Investigation . . 8
5.1 Non-destructive sewer condition investigation techniques .8
5.2 CCTV good practices .10
5.2.1 General .10
5.2.2 Australian context .10
5.2.3 Objective .11
5.2.4 Methodology . .11
5.3 Automated CCTV condition assessment . 12
5.3.1 General . 12
5.3.2 Context . 12
5.3.3 Activities . 12
5.3.4 Benefits . 12
5.4 Hydraulic investigation. 13
5.4.1 General . 13
5.4.2 Flow monitoring . 13
5.4.3 Hydraulic modelling . 13
6 Assessment . .13
6.1 Deterioration predictive models . 13
6.2 Assess maturity of operations to define action plans .14
6.3 Treatment plant: implementation of simplified and monetized FMECA (Failure Mode,
Effects and Criticality Analysis) . 15
7 Implementation: sustainable field works . 17
8 Operation and maintenance . 17
8.1 Odour management .17
8.1.1 General .17
8.1.2 Australian context .18
8.1.3 Objective .18
8.1.4 Methodology . . .18
8.2 Dynamic simulation for condition analysis and process optimization for a wastewater
treatment plant (WWTP).19
8.2.1 General .19
8.2.2 Context and objectives .19
8.2.3 Outcomes .21
8.3 Monitoring and control .21
8.3.1 General .21
8.3.2 Hypervision . 22
8.3.3 Integrated information systems . 22
8.4 Monitoring . 22

iii
9 Rehabilitation .23
9.1 Network renewal plan . 23
9.2 Rehabilitation strategies based on condition and material deterioration analysis and
forecasting . . . 23
9.3 Plant renewal plan. 29
Annex A (informative) Summary of examples of good practices for asset management of
wastewater systems .30
Bibliography .33

iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
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This document was prepared by Technical Committee ISO/TC 224, Drinking water, wastewater and
stormwater systems and services.
A list of all parts in the ISO 24589 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
Introduction
This document is written within the overall concept of asset management which is an activity all
organizations undertake in some manner and to some degree. It focusses on the details of managing the
physical assets at the operational level rather than the organizational (corporate management) level.
Water services are reliant on their assets to deliver their services to the resident populations in their
jurisdictions. The assets (underground pipes, reservoirs, storage tanks, treatment plants, etc.) collectively
form the physical infrastructure of the water services and are the consequence of the accumulated capital
investments and operational expenditures on maintenance and rehabilitation over many years. In many of
these services, the replacement value of these past investments amounts to many millions (even billions)
of dollars depending on the size of the community served. Therefore, the infrastructure represents a major
societal investment in essential services contributing to public health and the protection of the environment.
In many countries, these assets have been identified as critical infrastructures and programs are in place to
assure their protection or their sustainability. Like many other organizations having assets, water services
undertake programs of activities to manage the assets to ensure they continue to meet the needs of the
community for reliable delivery of potable water. These management activities can be at the strategic,
tactical or operational level. The activities can be part of a formal management system, or the result of
specific legislative requirements, or ultimately just the result of due diligence by the service operators and
managers.
This document is expected to serve as a supporting document for utilities operating management of assets
in accordance with ISO 24516.
In many countries there is a sustainability problem, sometimes referred to as the infrastructure gap: for
various reasons, the infrastructure has not been maintained over the years on a truly sustainable basis, in
other words funding of rehabilitation and replacement programs has been postponed, with a focus instead
on short term repairs, or an allowed decrease in the level of service provided.
The condition of water infrastructures greatly influences the adequacy of the water service, specifically its
quantity, pressure, quality, safety, reliability, environmentally friendly, degree of purification and economic
efficiency. System condition-based rehabilitation approaches serve to meet these requirements with a focus
on a holistic approach of condition-based, risk-oriented maintenance.
Once the installation and development of water assets is almost completed, the optimization of networks
will become necessary in many places in order to respond to changing societal and economic conditions.
Networks are subject not only to ageing as well as wear and tear, but also to adaptation processes resulting
from growth, new legislative requirements, or changing customer service level expectations. This requires
water utilities to focus increasingly on the growing need to rehabilitate existing water networks rather than
removing and replacing the networks. Rehabilitation will thus become essential in asset management, with
ever more stringent requirements on the design and execution of rehabilitation.
In recent years, much effort has been applied to the whole issue of asset management on two levels: what
are the principles and structure of an asset management system, and what are the good practices that
can be implemented on a technical level to assess the condition of the assets and help decide when asset
interventions (repair, rehabilitation or replacement) take place.
This document offers examples on how to define an asset management strategy with regard to the overall
performance expected by the owner. It includes several aspects of the operations and maintenance, including
asset condition assessment and investment (new assets, rehabilitation and renewal) strategies.
The focus will be on the following selected activities of the management of assets of wastewater systems as
addressed in ISO 24516-2 and ISO 24516-4).
— Clause 4 covers the principal aspects of the management of assets, including examples of:
— objectives;
— strategies;
vi
— structure of the process.
— Clause 5 covers the tools and methods for investigation, including operational data collection, tools for
diagnosis, other source of information along with key practical recommendations for implementation
and analysis of closed-circuit television (CCTV) investigation.
— Clause 6 covers the assessment of the system against its performance expectations for the following
aspects:
— practical tools and methods for structural, functional, hydraulic performance;
— examples of degradation factors and models of degradation;
— practical tools and methods for criticality assessment;
— examples of calculation to assess the likelihood of a failure.
— Clause 7 covers the implementation of sustainable field works, providing examples of what matters from
asset management point of view.
— Clause 8 covers the operation and maintenance by providing examples of monitoring and controlling flow
and quality, measuring combined overflow quantity and quality, cleaning and removal of obstructions
to restore hydraulic capacity, energy management, monitoring and control and maintenance of civil
structures.
— Clause 9 covers the prioritization of rehabilitation of assets with examples of how it is done practically.
The examples of good practice for asset management of wastewater systems covered in this document are
relevant to all types and sizes of organization and utilities operating wastewater systems.

vii
Technical Report ISO/TR 24589-2:2025(en)
Examples of good practice for the management of assets of
water supply and wastewater systems —
Part 2:
Wastewater systems
1 Scope
This document contains selected examples for good practice approaches for the management of assets of
wastewater systems. This document is intended as a supporting document for ISO 24516-3 and ISO 24516-4,
which contain guidelines for the management of assets of wastewater systems. As such, this document can
contribute to realize value from existing assets when following the guidelines for the management of assets
of wastewater systems approaches in the strategic, tactical and operational plans given in ISO 24516-3 and
ISO 24516-4.
NOTE A recapitulative table of the examples covered in this document is provided in Annex A.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principal aspects
4.1 Objectives
4.1.1 Multiple wastewater utilities
Table 1 contains an example of performance indicators that can be used to set objectives for multiple
wastewater utilities. This example is obtained from France. The good practice highlighted is the benchmark
to follow the performance of several public wastewater services by a professional association of private
operators (Reference [6]).
Table 1 — Performance indicators for multiple wastewater utilities
Performance indicator 2008 2010 2013 2017
Percentage of complaints (in relation to population) 3,2 % 2,5 % 0,2 % 0,4 %
Sewer system asset knowledge and management percentage (in relation to
— — 45,1 % 50,7 %
a
length)
Percentage of sewage sludge treated in a process that complies with the
94,7 % 98,5 % 97,4 % 99,8 %
applicable regulations (in relation to tonnes)
Number of sewer system locations requiring frequent cleaning (in relation 4,8 per 7,7 per 6,9 per 6,1 per
to length) 100 km 100 km 100 km 100 km
Existence of a Commission Consultative des Services Publics Locaux (in
71 % 70 % 67 % 76 %
relation to population)
a
The regulations changed in 2013. The new formula for calculating the index, introduced in 2013, factors in compliance with
the requirement to produce a detailed description of the network. Between 2008 and 2010, the scope of the survey expanded to
include utilities covering fewer than 10 000 people.
4.1.2 Collection network
Table 2 contains an example of performance indicators that can be used to set objectives for a collection
network. This example is obtained from France. The good practice highlighted is a standard set of
performance indicators monitored at country level by a national observatory body (Reference [7]).
Table 2 — Performance indicators
Indicator Unit
Coverage rate by centralized wastewater system %
Knowledge and asset management index of sewerage networks (until 2012) unit
Knowledge and asset management index of sewerage networks (after 2012) score
Compliance of effluent collection with the requirements defined pursuant to decree 94-469 of June
%
3, 1994 amended by the decree of May 2, 2006
Compliance of wastewater treatment plants with the requirements defined in application of decree
%
94-469 of June 3, 1994 modified by the decree of May 2, 2006
Compliance of the performance of wastewater treatment plants with the requirements defined
%
pursuant to decree 94-469 of June 3, 1994 amended by the decree of May 2, 2006
Rate of sludge from wastewater treatment plants evacuated according to channels that comply
%
with regulations
Amount of debt waivers or payments to a solidarity fund €/m
Effluent overflow rate in user premises nb/1 000 inhab.
Number of collection network points requiring frequent cleaning operations per 100 km network nb/100 km
Average rate of renewal of wastewater collection networks %
Compliance of the performance of the wastewater treatment plant with the specific prescriptions
%
delivered by the water authority in charge
Index of knowledge of discharges into the natural environment by wastewater collection networks unit
Duration of extinction of the debt of the community year
Rate of unpaid water bills from the previous year %
Complaints rate nb/1 000 inhab.
4.1.3 Treatment plants and other elements
Table 3 contains an example of objectives for a treatment plant in Spain. The good practices highlighted in
Table 3 include:
— ISO 55001 certified plant, with renewal objective;
— break-up of actions and indicators.

Table 3 — Plant asset management strategy
Owners –
Type of Goals and Periodicity and Records and
Processes/origin responsible – Indicator Remarks Target value
a
indicator actions dates documents
resources
Implement an asset manage- Plant manager/ Q Renewal of ISO 55001 certifica- Obtaining a Phase 1 external 04/04/2019 —  ISO 55001 cer-
ment system that consoli- external certify- tion in May 2019. certificate. audit, documen- tificate
08/05/2019
dates the experience of the ing company tary.
—  Internal audit
plant’s management team
Phase 2 external plan
and ensures optimal asset
audit implemen-
—  Action plan
management.
tation.
Endorse the professional ties Plant manager / Q Joint Assessment of the condition List of evaluat- 1.  Customer 1.  Initial List of evaluated
with the client, through a client of assets by the asset condition ed equipment training equipment (ACA)
2.  Initial and
win-win relationship, com- assessment (ACA) method. (ACA)
2.  Joint assess- final contractual
plying with and enforcing
ment condition period
the contractual and legal
assets client
3.  Initial and
framework, in addition to ac-
– driving equip-
final contractual
companying in the technical
ment
period
challenges.
3.  Decline of
results in asset
registry
AM Monetized impact of unrealized  Monthly —  Minutes of
corrective maintenance (critical meetings
and non-critical) that depends on
—  Monthly data by
the client
registration
I = sum of the monetized
GA7
criticality of unrealized correc-
tive maintenance (critical and
non-critical) that depends on the
customer
EE I = kWh consumed / m treated Comparison of Semi-annual Indicators and
GE1
water previous years objectives report
Env
I = kg of chemical reagents con-
AM O5
sumed / m treated water
Q
Comply with and enforce in Coordinator qual- Q Internal and external audits relat- At least one Carry out an an- Annual —  Program annual
a holistic and optimal way ity management ed to asset management; internal audit nual audit plan. internal audits
the management systems per year once
Internal: evaluate the possibility —  Internal and
(OSHAS 18001, ISO 14001, certification is
of doing cross-audits with other external audit plan
ISO 9001, ISO 50001, achieved.
entities in 2020.
—  Internal and ex-
ISO 55001), ensuring the
External: monitoring by external ternal audit report
competence required for the
auditor.
perenniality and sustainabil-
ity of the process.
a
Types of indicators: Q = Quality, EE = Energy management, Env = Environment, S = Safety, AM = Asset management

Table 3 (continued)
Owners –
Type of Goals and Periodicity and Records and
Processes/origin responsible – Indicator Remarks Target value
a
indicator actions dates documents
resources
Ensure the integrity and Plant manager S Number of accidents with sick KPI analysed monthly 1 accident with- Monthly Accident plan of the
well-being of staff. leave and without sick leave with the plant manage- out sick leave centre

ment.
0 accidents
Compliance with the with sick leave
organization’s accident
target.
It is an indicator at the
workplace level.
Q Perform evaluation of the compe- Verify that you have the At least 50 %  —  Action plan
tencies required for asset manage- competencies required of the staff
—  Matrix of com-
ment to the personnel involved. for asset management involved in the
petences
(identify competencies, 2019 asset man-
—  Priority training
operating plan, training agement system
plan
plan, procedure profes- and 100 % in
—  Employment
sional categories, etc.). 2020.
Authorization Docu-
ments (EAD)
Study the optimization of Plant manager AM I = renovation costs / replace- —  Asset management  Quarterly The data that feeds
GA1
the total cost of the life cycle ment value of equipment KPIS these indicators are

(LCC) of the assets. analysed monthly
I = Total cost of preventive —  Preventive mainte-
GA2
in the asset man-
maintenance / Total cost of the nance value > correc-
agement indicators
plant tive maintenance value
dashboard.
I = Total corrective mainte-
GA3
nance cost / Total plant cost
Investments over € 10 000 with 1 Make LCC for invest-
LCC / investments over € 10 000. ments over € 10 000
before the purchase
order.
Mobilize the necessary Plant manager Q Have the risk assessment, training 1 Action plan
human, material and plan, EAD.
financial resources in order
to implement the strategic
asset management plan.
a
Types of indicators: Q = Quality, EE = Energy management, Env = Environment, S = Safety, AM = Asset management

Table 3 (continued)
Owners –
Type of Goals and Periodicity and Records and
Processes/origin responsible – Indicator Remarks Target value
a
indicator actions dates documents
resources
Promote the continuous Plant manager Q/S/ Report 1 REX file per average year 2 Contract dura- REX tab
improvement of the asset Env/EE/ of the contract period. tion

management system. AM
AM Update of the criticality plan once 1 Criticality plan

a year and whenever there is a
relevant change.
AM Impact of planned and unrealized I = 0 Weekly mainte- Dashboard AM
GA5
maintenance orders (Critical and nance meetings
I = 0
GA6
non-critical)
I = number of critical equip-
GA5
ment orders not performed /
number of critical equipment
orders planned
I = sum of monetized criticality
GA6
of critical equipment with planned
and unrealized order
AM I = Planned maintenance or- Asset management > 90 % Quarterly The data that feeds
GA4
ders / maintenance orders made. KPIS. these indicators are
analysed quarterly
in the asset man-
agement indicators
dashboard.
Promote close cooperation Plant manager Q/S/ Perform audit of the 5S. 1 Initial and Audit report
between all processes in- Env/EE/ annual
volved in asset management.
The application of the asset Plant manager Q Implementation of the asset man- —  Maintenance 1 —  Action plan
management policy together agement system in the workplace ISO 55001 certification
—  Audit plan
with the support of the func- and ensuring compliance with
—  Indicators
—  Monitoring
tional teams and integrated said management system.
—  Audits indicators
management system.
—  Action plan
—  Awareness talks
—  Training/compe-
tences.
Ensure communication and Plant manager Q/S/ Make communications plan. Make communi- Communications
understanding of this policy Env/EE/ cations plan = 1 plan
at all levels of the organiza- AM
tion.
a
Types of indicators: Q = Quality, EE = Energy management, Env = Environment, S = Safety, AM = Asset management

4.2 Strategies
4.2.1 Maintenance strategy
Figure 1 contains an example of preventive maintenance (PM) strategy based on criticality analysis for a
treatment plant in Jordan.
Figure 1 — Preventive maintenance
Table 4 illustrates corrective maintenance prioritization based on criticality analysis for a treatment plant
in Jordan.
The prioritization of corrective maintenance is given by operation team, based on operational context and
following criteria of Table 4.
Table 4 — Corrective maintenance
Priority rank Criteria Detail
1 Safety impact
2 Water treatment and/or environmental impact Priority per volume/hour at stake
3 Cost impact Priority per cost/hour at stake
4 Operational inconvenience
5 Availability of required material and human resources
The priority is expressed as:
— very urgent (today);
— important (2 days);
— normal (week);
— minor (month).
4.2.2 Renewals decision
Figure 2 illustrates renewal prioritization for assets to be renewed at a treatment plant in Jordan. The good
practices highlighted in Figure 2 include:
1)
— methods applied at an ISO 55001:2014 certified site;
— prioritization based on criticality analysis, condition assessment and funding.
Figure 2 — Prioritization of renewals
4.2.3 Inspection strategy of collection network
This example is obtained from France. The highlighted good practices include:
— clustering of representative groups of pipes, selection of samples;
1) Withdrawn.
— diagnosing to rapidly identify where and when network interventions are required;
— calibration of degradation model based on inspections of samples;
— extrapolation to whole network.
Best tools and techniques for asset condition diagnosis are defined based upon the utility’s experience as an
operator and considering local specificities (service organization, sub-contracting, etc.).
To optimize the planning of investigations of non-visitable main sewers, a 2 steps activity is conducted:
a) Step 1: perform an initial study to create a map of sectors classified on the basis of structural risk:
— inventory and prioritization of criteria which can affect and speed up the deterioration of main
sewers (date of installation, depth, presence of vegetation, etc.) accompanied by vulnerability factors
(diameter, urban infrastructure, vulnerable locations, etc.);
— historical records of CCTV inspections of networks carried out in previous years;
— network inspections by means of swift TV inspection (video-periscope);
— capitalizing on the results by means of a specific software application integrated into the Geographic
Information System;
b) Step 2: based on this study, a structural risk chart is prepared. Based upon this risk analysis, an
optimized long-term program of CCTV inspections is established.
Besides visual inspections, non-intrusive techniques can be applied, such as radio detection and sonar.
For the specific case of service connections of separate sewer systems, the absence of cross connections is
checked. For that purpose, the method is to use dedicated equipment that enables only one field operator to
carry out dye tests and acoustic tests with a hand-held computer and a mobile monitoring kit. In that manner,
the operator can complete tests in various checkpoints of a given private property on their own. Those tests
are performed by installing sequentially the mobile monitoring kit on the manhole of the sanitary drain and
on the manhole of the storm drain.
5 Investigation
5.1 Non-destructive sewer condition investigation techniques
Table 5 illustrates usual non-destructive sewer condition investigation techniques, with application
objectives. This example is obtained from France.

Table 5 — Main sewer investigation techniques
Technique Description Objectives
CCTV of sewer Use of an inspection robot fitted with a camera — Collect information about the sewer
lines and house and an inclinometer (if available) including: pipe (material, position of connections,
service diameter, length, depth at access
— all the preparation (cleaning, pumping, road
connections manholes).
permissions, barricading, etc.);
— Generate a report on the damages to the
— generate inspection reports as per the
sewer.
standard EN 13508-2;
— Record the water inflows on the day of
— additional comments from the videographer
inspection.
for each defect and inspected segment.
— Keep record in the CCTV database and
the GIS and enhance it as needed.
Radar Apply one or more generators and halo of a radar Provides an image of the buried sewer, its
antenna (there are several antenna interface with the surrounding soil. This
characteristics). method requires calibration surveys.
This technique can also be used from the
surface to characterize subsidence or detect
buried networks.
Jacking tests Test of loading and unloading of the sewer pipe Identify variations of mechanical
which makes it possible to obtain the stiffness of characteristics of the sewer and detect
the pipe at each measurement point. voids on the extrados.
Ferroscan Punctual passage of a probe according to a Used to assess the reinforcement of an
predefined grid. infrastructure.
Mechanical Recording and analysis of the structural response Identify variations of mechanical
impedance of an infrastructure following a shock. This can characteristics of the sewer and detect
be obtained by the fall (manual or automatic) of a voids on the extrados.
mass.
Sonar Use a sonar probe on a carrier (rolling or floating) Identify the level of fouling of the sewer
without drying the sewer. This technique can without prior drying.
be coupled with video inspection or digitization
Follow the evolution of the fouling between
(Lidar) of the non-submerged part.
two inspections.
Identify the areas requiring detailed
auscultation.
Lidar Probe allowing the three-dimensional digitiza- Generate a 3D model of the infrastructure,
tion of the infrastructure (manholes, pipes, etc.). necessary for numerical calculations, moni-
The probe can be placed in the sewer on a carrier toring of the evolution of the infrastructure,
and be coupled with video inspection or sonar virtual visits, etc.
auscultation.
Sampling Collect sewer samples from outside or inside Calibrate all the non-destructive inspections
(visitable sewers) and soil samples. methods.
Reproduced with permission from Reference [8].
The following are different types of visual inspection tools.
— Video-periscope or pole camera enable images to be taken inside sewer mains and connections via a
manhole to observe aspects of the wall and the level of fouling. A camera is lowered down to the level of
the sewer mains where the image is taken.
— Water-propelled camera are propelled thanks to pressurized water from a cleaning nozzle. The use of a
camera enables the quality of cleaning to be more efficiently controlled and at the same time to provide
an image of the inside of the sewer mains.
— Satellite camera is a camera that is incorporated into a classic inspection system. The satellite camera is
inserted into the connection from the sewer mains.
Fisheye cameras are cameras which enable photos to be taken along the entire length of pipe or a radial
photo to be taken, producing a comprehensive view of the inside of a pipe. They are so called because the

lens, which has a hemispherical shape, looks like a fish eye. This shape allows the lens to capture an image
at a very wide angle up to 180°.
5.2 CCTV good practices
5.2.1 General
This example it obtained from Australia. The highlighted good practices include:
— improving pipe selection for CCTV;
— improving quality of CCTV footage and defect scoring;
— separate manhole classification system.
5.2.2 Australian context
The performance of a sewer network is fundamental to the achievement of customer, environment and
efficiency outcomes. The safe and unobtrusive removal of sewage is a fundamental expectation of customers,
as well as the need to protect the environment through sustainable discharge at the lowest community
cost. Gravity sewer main management is transitioning from reactive to proactive management. Proactive
management has been shown to be far more cost effective than reactive while also minimizing the impact
on the community and environment. A major tool in this transition is condition assessment using of CCTV.
Australia has a defect categorization analysis code which is used throughout the industry: “Conduit
Inspection Reporting Code of Australia”. The code includes:
— a specification for CCTV software;
— a complex defect coding system to describe cracking, deformation and corrosion;
— an approach for scoring defects.
This code is used by all water utilities and service providers in Australia to identify and classify sewer defects
resulting in assessment of sewer risk and prioritizing of investment programs. Condition is a measure of
both serviceability and structural integrity.
CCTV is typically programmed based on risk. A typical 5 × 5 risk matrix for CCTV is shown in Table 6.
Table 6 — Risk matrix for CCTV
Criticality rating
Condition
grade
AAA A B C D
Immediate CCTV Immediate CCTV Immediate CCTV Program for CCTV
5 Immediate CCTV
3 months 6 months 6 months 12 months
Immediate CCTV Program for CCTV Program for CCTV Program for CCTV Program for CCTV
6 months 12 months 12 months 12 months 24 months
Program for CCTV
Program for CCTV Program for CCTV Program for CCTV Program for CCTV
3 only if abnormal
24 months 24 months 36 months 36 months
condition for age
Program for CCTV
Program for CCTV Program for CCTV
2 only if abnormal No action No action
48 months 48 months
condition for age
1 No action No action No action No action No action

5.2.3 Objective
To reduce the number of service interruptions from sewer blockages or structural failures without an
unaffordable increase in water bills. This has involved a three phased approach:
— improving the selection of sewer pipes for CCTV;
— improving the quality of CCTV footage defect scoring;
— improving the classification of defects in access chambers.
5.2.4 Methodology
5.2.4.1 Improving pipe selection
The Australian utilities are progressively CCTVing larger proportions of the sewer network. Some utilities
are as high as 30 % of the network though most are at 10 %. Monitoring the effectiveness of CCTV in
identifying sewers in poor condition is part of this process. More work is performed on prioritising CCTV
as typically only 5 % of CCTVed sewers are condition rating 5 an
...