ISO 24527:2020

Service activities relating to drinking water supply, wastewater and stormwater systems - Guidelines on alternative drinking water service provision during a crisis

This document provides guidelines on alternative drinking water service (ADWS) provision during a crisis. This document addresses: a) ADWS principles and methods; b) ADWS operational planning and implementation. This document is not applicable to: 1) planned water supply interruptions forming part of drinking water utilities' normal operations; NOTE However, many of the principles and methods described can be appropriate in such circumstances. 2) drinking water supplied for the ongoing operation of key establishments and facilities during a crisis, such as hospitals, homes for the aged, schools, reception facilities and vital plants; 3) water supplied for industrial, agricultural or commercial purposes; 4) water supplied to temporary settlements such as refugee camps; 5) the development and implementation of a crisis management system for water service, which is covered by ISO 24518 and ISO/TS 24520.

Activités de service relatives aux systèmes d'alimentation en eau potable, aux systèmes d'assainissement et aux systèmes de gestion des eaux pluviales — Lignes directrices relatives à l'approvisionnement alternatif en eau potable en cas de crise

General Information

• Status: Published
• Publication Date: 29-Apr-2020
• ICS: 03.080.30 - Services for consumers
• ICS: 13.060.20 - Drinking water
• Technical Committee: ISO/TC 224 - Drinking water, wastewater and stormwater systems and services
• Drafting Committee: ISO/TC 224/WG 7 - Crisis management of water utilities
• Current Stage: 9093 - International Standard confirmed
• Start Date: 03-Sep-2025
• Completion Date: 13-Dec-2025

Overview

ISO 24527:2020 - Service activities relating to drinking water supply, wastewater and stormwater systems - provides international guidelines on alternative drinking water service (ADWS) provision during a crisis. It is intended for drinking water utilities that normally deliver uninterrupted service via a distribution network and need guidance on planning, implementing and communicating emergency or extended-disruption water supply solutions.

The standard covers ADWS principles and methods, and ADWS operational planning and implementation. It is focused on supplying drinking water to the public during crises (not routine planned interruptions) and explicitly excludes supply for hospitals and other key facilities, industrial/agricultural use, refugee camps, and full crisis management systems (see Related standards).

Key technical topics and requirements

ISO 24527:2020 addresses practical, operational topics including:

• ADWS principles - two complementary approaches:
  • Using the distribution network in a non-conventional manner, and
  • Not using the distribution network (alternative distribution methods).
• Operational planning - pre‑planning, scenario development, resource identification, and mobilization strategies for extended disruptions.
• Implementation methods - examples and guidance (informative) on:
  • Erecting standpipes,
  • Recharging isolated network assets with water tankers,
  • Lowering supply pressure when appropriate,
  • Temporary points of distribution,
  • Containerized drinking water (bottles, static tanks, bowsers),
  • Fixed water resources and mobile tankers/towed bowsers.
• Communications - internal and external messaging before and during crises, tailored messaging, stakeholder preparation, and what/how to communicate.
• Special needs - considerations and adaptations for vulnerable user groups.
• Informative annexes - layouts for distribution points, containerized water guidance, allocation methods, logistics and process modifications for special needs.

The document focuses on practical guidance rather than prescriptive technical specifications and limits water-quality coverage to what’s relevant for ADWS.

Practical applications and who should use it

ISO 24527:2020 is useful to:

• Drinking water utilities and operators planning business continuity and emergency response,
• Municipal emergency planners and public health authorities coordinating community-level water response,
• Logistics and operations teams deploying tankers, containers or temporary distribution points,
• NGOs and disaster-response organizations involved in supplying potable water during crises.

Use cases include earthquake- or flood-impacted systems, major contamination events or infrastructure failures where normal distribution is compromised.

Related standards

• ISO 24518 and ISO/TS 24520 - crisis management systems for water services (complementary).
• ISO 24513 - vocabulary used across service activities relating to drinking water supply.

Keywords: ISO 24527:2020, alternative drinking water service, ADWS, emergency water distribution, drinking water supply, crisis planning, water utilities, containerized drinking water, standpipes, water tankers.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 24527
First edition
2020-04
Service activities relating to drinking
water supply, wastewater and
stormwater systems — Guidelines on
alternative drinking water service
provision during a crisis
Activités de service relatives aux systèmes d'alimentation en eau
potable, aux systèmes d'assainissement et aux systèmes de gestion des
eaux pluviales — Lignes directrices relatives à l'approvisionnement
alternatif en eau potable en cas de crise
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles for alternative drinking water service provision . 5
4.1 General . 5
4.2 Alternative drinking water service approaches . 5
4.2.1 General. 5
4.2.2 Using the drinking water distribution network in a non-conventional manner . 5
4.2.3 Not using the drinking water distribution network . 5
5 Planning for alt ernative drinking water service provision . 6
5.1 General . 6
5.2 Pre-planning . 6
5.2.1 Establishing individual disruption scenarios . 6
5.2.2 Pre-planning in accordance with the disruption scenario . 6
5.3 Securing resources and planning for their mobilization . 7
6 Implementation of alternative drinking water service provision . 9
6.1 General . 9
6.2 Non-conventional methods for drinking water distribution network use . 9
6.2.1 General. 9
6.2.2 Distribution of drinking water by erection of standpipes . 9
6.2.3 Recharging of isolated drinking water distribution network assets by
water tankers . 9
6.2.4 Lowering the pressure at which drinking water is supplied .10
6.3 Methods not using the drinking water distribution network .10
6.3.1 General.10
6.3.2 Temporary point of distribution methods .10
6.3.3 Containerized drinking water .10
6.3.4 Via a fixed water resource .11
6.3.5 Via mobile water tankers or towed bowsers .11
7 Internal and external communications .11
7.1 General .11
7.2 Preparing stakeholders in advance of a crisis involving alternative drinking water
service provision .12
7.2.1 Tailored messaging .12
7.2.2 Preparing users .12
7.2.3 Preparing key stakeholders .12
7.3 Alternative drinking water service information during a crisis .12
7.3.1 General.12
7.3.2 How to communicate .12
7.3.3 What to communicate .14
8 Alternative drinking water service provision for users with special needs.14
Annex A (informative) Examples of layouts of, and assets deployment at, temporary points
of distribution .16
Annex B (informative) Containerized drinking water .19
Annex C (informative) Determining drinking water allocations .27
Annex D (informative) The logistics of alternative drinking water service provision .29
Annex E (informative) Modification of standard alternative drinking water service
processes to support users with special needs .34
Bibliography .35
iv © ISO 2020 – All rights reserved

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 ISO technical committees. Each member body interested in a subject for which a technical
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 224, Service activities relating to drinking
water supply, wastewater and stormwater systems.
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.
Introduction
Drinking water is fundamental to life and its distribution is considered to be an essential service.
Drinking water supply relies on systems that can be subject to disruption from internal or external
factors including operational error, lack of rehabilitation, damage to the drinking water system,
malicious acts (e.g. vandalism, criminality or terrorism) and natural disasters (e.g. earthquakes, floods,
hurricanes or volcanic eruptions).
This document is intended for drinking water utilities that normally provide a service without
interruption through a drinking water distribution network. It provides guidelines for the effective
implementation of alternative drinking water service (ADWS) provision during extended periods of
disruption to drinking water supply.
In many cases, operational and organizational processes will exist within drinking water utilities to
deal with short periods of localized interruption to drinking water distribution. However, if the service
interruption exceeds the duration or extent of anticipated events, an interruption can escalate into a
crisis at local, regional or, exceptionally, national levels.
NOTE 1 For adequacy and consistency, guidance in this document typically assumes an operational response
at a crisis level. However, the guidelines are applicable for all levels of operational incidents requiring ADWS
deployment including normal business continuity preparedness and response.
NOTE 2 For guidance on the management of crises see ISO 24518 and ISO/TS 24520.
A significant water interruption (arising from quantity and/or quality issues) can impact public and
personal health and wellbeing, and economic performance. A prolonged interruption can progressively
threaten the coherence of the community served.
The roles of relevant authorities, responsible bodies, drinking water utilities and operators can differ
between and within countries and result in different minimum requirements for ADWS provision.
Nevertheless, it is generally recommended that such organizations recognize the importance of
uninterrupted drinking water distribution, even at times of crisis for the drinking water utility, for the
wellbeing of the community served.
Drinking water utilities are encouraged to reduce the risk of water supply interruption. This is
typically achieved by a combination of good planning, design, procurement, installation, operation and
maintenance of the drinking water assets. Such measures should include the provision of an ADWS for
users during a crisis.
It is also recommended that the drinking water utility's capability to provide an ADWS will be consistent
with the maximum likely service interruption (extent and duration) identified through risk assessment.
The provision of an ADWS necessitates thorough preparation (e.g. to address planning, procurement,
logistics, control and communication), as well as awareness of the need and commitment at all levels of
the organization to be effective and efficient.
ADWS during a crisis can be provided using one of the two following principles, or both in combination:
a) using the drinking water distribution network in a non-conventional manner;
b) not using the drinking water distribution network.
This document describes the principal issues to be considered when:
1) planning for and deploying ADWS provision;
2) anticipating and addressing stakeholders’ ADWS needs and communicating with stakeholders on
ADWS deployment.
ADWS planning and provision can include guidelines by responsible bodies on monitoring and control
methods. This document covers water quality issues only to the extent that they relate to drinking
water provided via an ADWS.
vi © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 24527:2020(E)
Service activities relating to drinking water supply,
wastewater and stormwater systems — Guidelines on
alternative drinking water service provision during a crisis
1 Scope
This document provides guidelines on alternative drinking water service (ADWS) provision during
a crisis.
This document addresses:
a) ADWS principles and methods;
b) ADWS operational planning and implementation.
This document is not applicable to:
1) planned water supply interruptions forming part of drinking water utilities’ normal operations;
NOTE However, many of the principles and methods described can be appropriate in such circumstances.
2) drinking water supplied for the ongoing operation of key establishments and facilities during a
crisis, such as hospitals, homes for the aged, schools, reception facilities and vital plants;
3) water supplied for industrial, agricultural or commercial purposes;
4) water supplied to temporary settlements such as refugee camps;
5) the development and implementation of a crisis management system for water service, which is
covered by ISO 24518 and ISO/TS 24520.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 24513, Service activities relating to drinking water supply, wastewater and stormwater systems —
Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 24513 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
alternative drinking water service
ADWS
drinking water provided to users (3.15) by means other than through the normal drinking water system
Note 1 to entry: ADWS can be required due to the loss of supply or due to the fact that the water currently being
supplied is believed unfit for the intended use.
Note 2 to entry: For the purposes of this document, ADWS only refers to the supply of drinking water. There
can, however, be occasions where it is decided for public health (e.g. toilet flushing) and safety (e.g. firefighting)
reasons to temporarily supply non-drinking water via the drinking water distribution network in parallel with
an ADWS.
3.2
containerized drinking water
packaged water
drinking water (3.4) deployed in containers for ADWS (3.1) provision
EXAMPLE 1 Bottled water, pre-prepared and hygienically sealed, with a predetermined shelf-life.
EXAMPLE 2 A personal water bag, pre-prepared but empty, and filled during an incident.
EXAMPLE 3 Static water tanks; towed bowsers; mobile water tankers, disinfected and deployed, and filled
during an incident.
3.3
crisis
event or situation which affects or is likely to affect the organization or its provided services which
requires more than the usual means of operation and/or organizational structures to deal with it
3.4
drinking water
DEPRECATED: potable water
water intended for human consumption
Note 1 to entry: Requirements for drinking water quality specifications are generally laid down by the national
relevant authorities (3.10). Guidelines have been established by the World Health Organization (WHO).
3.5
drinking water allocation
daily per-capita drinking water (3.4) quota to be supplied to users during ADWS (3.1) provision
Note 1 to entry: The relevant authority (3.10), the responsible body (3.11) or the drinking water utility (3.7) (in the
absence of guidance from the relevant authority or responsible body) can determine drinking water allocation(s)
for categories of user (3.15).
Note 2 to entry: Drinking water allocations can differ between categories of user and can exclude some categories
of user.
Note 3 to entry: The size of drinking water allocations can be varied at different times during the crisis (3.3).
EXAMPLE Per-capita domestic user in first 12 h of crisis response; per-capita per-day domestic user after
first 12 h; per-capita per-day special needs user.
3.6
drinking water distribution network
asset system for distributing drinking water (3.4)
Note 1 to entry: Drinking water distribution network can include pipes, valves, hydrants, pumping stations and
reservoirs, and other metering and ancillary infrastructure and components.
Note 2 to entry: Pumping stations and reservoirs can be sited either in the waterworks or in the drinking water
distribution network.
2 © ISO 2020 – All rights reserved

3.7
drinking water utility
whole set of organization, processes, activities, means and resources necessary for abstracting,
treating, distributing or supplying drinking water (3.4) and for providing the associated services
Note 1 to entry: Some key features for a drinking water utility are:
— its mission, to provide drinking water services;
— its physical area of responsibility and the population within this area;
— its responsible body (3.11);
— the general organization with the function of operator being carried out by the responsible body, or by legally
distinct operator(s);
— the type of physical systems used to provide the services, with various degrees of centralization.
Note 2 to entry: The term “drinking water utility” addresses a utility dealing only with drinking water.
Note 3 to entry: When it is not necessary or it is difficult to make a distinction between responsible body and
operator, the term “drinking water utility” covers both.
Note 4 to entry: In common English, “drinking water service” can be used as a synonym for “drinking water
utility”, but this document does not recommend using the term in this way.
3.8
interruption
situation where the service is not available or only partially available
Note 1 to entry: Interruptions can be planned or unplanned.
3.9
management
coordinated activities to direct and control a drinking water utility (3.7)
Note 1 to entry: Management can include establishing policies and objectives, and processes to achieve these
objectives.
Note 2 to entry: The word “management” sometimes refers to people, i.e. a person or group of people with
authority and responsibility for the conduct and control of a service. When “management” is used in this sense, it
should always be used with some form of qualifier to avoid confusion with the concept “management” as a set of
activities defined above. For example, “management should…” is deprecated whereas “crisis management team
should…” is acceptable. Otherwise, different words should be adopted to convey the concept when related to
people, for example managerial or managers.
Note 3 to entry: The term “management” can be qualified by a specific domain it addresses. Examples include
public health management, environmental management and risk management.
3.10
relevant authority
organization with appropriate statutory powers of control
EXAMPLE National, regional or local governments, public agencies, regulators.
Note 1 to entry: Relevant authority is a category of stakeholder (3.13).
Note 2 to entry: For a given drinking water utility (3.7) there can be several relevant authorities, which have
jurisdiction in different domains.
3.11
responsible body
body that has the overall legal responsibility for providing drinking water (3.4), wastewater or
stormwater services for a given geographic area
EXAMPLE A local or municipal government (e.g. for a village, town or city), a regional government, a national
or federal government through a specified agency or a private company.
Note 1 to entry: Responsible body is a category of stakeholder (3.13).
Note 2 to entry: The responsible body can be legally distinct, or not, from the operator(s). The responsible body
can be public or private.
Note 3 to entry: The responsible body acts within a framework of law and governance established by the relevant
authorities. It generally establishes the strategy, the specific policies adapted to the characteristics of its area of
responsibility and the general organization of the relevant water utility.
Note 4 to entry: The responsible body can operate the water utility directly with its own means through an
internal operator (direct or internal management (3.9) or “in house”) or entrust one or several operators for the
operations (“outsourced” or contracted management).
3.12
service area
local geographic area where an organization has the legal or contractual responsibility to provide
a service
Note 1 to entry: The service area can be established, for example, by political boundaries (e.g. citywide utility),
legislative action (e.g. formation of a utility district) or interjurisdictional agreements (e.g. intercity agreements
to provide wastewater services).
3.13
stakeholder
interested party
person or organization that can affect, be affected by, or perceive itself to be affected by a decision or
activity
EXAMPLE Users (3.15) and building owners, relevant authorities (3.10), responsible bodies (3.11), operators,
employees of the operator, external product suppliers and providers of other services, contractors, communities,
customers and environmental associations, financial institutions, scientific and technical organizations,
laboratories.
Note 1 to entry: Stakeholders will typically have an interest in the performance or success of an organization.
Note 2 to entry: For the application of this document, environment is considered as a specific stakeholder.
3.14
temporary point of distribution
TPD
temporary interface where the user (3.15) can access an alternative drinking water service
3.15
user
DEPRECATED: consumer
person, group or organization that benefits from drinking water (3.4) delivery and related services,
wastewater service activities, stormwater service activities or reclaimed water delivery and related
services
Note 1 to entry: Users are a category of stakeholder (3.13).
Note 2 to entry: Users can belong to various economic sectors: domestic, institutional, commercial, industrial or
resource exploitation (e.g. agricultural, forestry, mining).
4 © ISO 2020 – All rights reserved

Note 3 to entry: The term “consumer” can also be used, but in most countries the term “user” is more frequent
when referring to public services.
Note 4 to entry: For the purpose of this document the term only refers to individuals and not organizations.
4 Principles for alternative drinking water service provision
4.1 General
In order to determine its ADWS provision, a drinking water utility should first have a clear
understanding of its normal operation during typical (non-crisis) circumstances.
During a crisis involving an interruption to drinking water distribution, the drinking water utility
should ensure an ADWS is provided to users and also ensure that assets which are intended to be used
in contact with drinking water are authorized by the relevant authority. Such assets could include
cleaned and disinfected drinking water containers.
Ideally, users should only take containerized drinking water according to predetermined drinking
water allocation(s), see Annex C. However, in practice, with high user demand and limited drinking
water utility resources available to control the issuing of drinking water, this can be difficult to achieve.
The drinking water utility's pre-planning of issuing drinking water should aim to ensure a suitable
level of control, including a contingency for excessive withdrawals. Inability to exercise such control can
lead to legitimate users' needs remaining unfulfilled. This can have consequences, including a decline
in ADWS service levels and financial and reputational impacts. Drinking water utilities can encourage
users to exercise restraint by providing adequate public information both in advance of and during a
crisis (see Clause 7).
The required water quality for ADWS provision is determined by the relevant authorities and/or
responsible bodies. However, the possible need to distribute non-drinking water through the drinking
water distribution network (if necessary, and in parallel with ADWS) should also be recognized. Such
a measure can be necessary for public health (e.g. toilet flushing) and public safety (e.g. firefighting)
reasons. In such circumstances, the water usage constraints that need to be complied with should be
strongly emphasized through stakeholder communications.
4.2 Alternative drinking water service approaches
4.2.1 General
The drinking water utility can adopt one or both of the ADWS approaches described in 4.2.2 and 4.2.3.
4.2.2 Using the drinking water distribution network in a non-conventional manner
This approach involves the drinking water utility supplying drinking water to users via the drinking
water distribution network but using different means than the regular operational methods.
Proven methods of ADWS provision using the distribution network in a non-conventional manner are
described in 6.2.
4.2.3 Not using the drinking water distribution network
This approach involves temporary points of distribution (TPDs) being established throughout the
affected service area. Examples of TPD methods are described in Annex A. The drinking water utility
should, during its normal operations (i.e. prior to the onset of a crisis), have communicated to users the
need to approach a TPD to receive drinking water during a crisis. This approach allows the drinking
water utility to provide users with drinking water reasonably close to their normal point of use.
Proven methods of ADWS provision not using the drinking water distribution network are
described in 6.3.
5 Plannin g for alternative drinking water service provision
5.1 General
ADWS provision should form an integral part of the drinking water utility's wider crisis management
response.
During normal operation, and based on a risk assessment, the drinking water utility should identify the
disruption scenarios that can lead to the need for ADWS provision and which cannot be managed by the
drinking water utility's normal organizational structures and operational means.
The drinking water utility should take into consideration that more than one approach and method can
be used during a crisis. The drinking water utility should decide upon the preferred approaches and
methods for ADWS provision, according to the considerations listed in 6.1.
The drinking water utility should prepare engineering, operational and logistical plans to implement its
chosen approach(es) to ADWS provision. The methods of ADWS provision selected should be planned
and exercised during times of normal operation, and responders should be appropriately trained in
order to demonstrate their readiness when required.
5.2 Pre-planning
5.2.1 Establishing individual disruption scenarios
The drinking water utility should take the following into consideration:
a) possible circumstances of the crisis;
b) relevant characteristics of the drinking water system of individual service areas, such as gravity
fed/pumped areas; pressure zones; and water quality features/constraints;
c) characteristics of the environment of individual service areas, such as rural/urban distinctions
and topographical features that provide access or act as barriers (e.g. highways, rivers, railways);
d) characteristics of the users in individual service areas;
e) its available resources (including personnel).
5.2.2 Pre-planning in accordance with the disruption scenario
Based on each crisis scenario, the drinking water utility should:
a) decide on the type and, where applicable, quantity of ADWS resources to be deployed (e.g. bottled
water, water tankers) and the timescale for their provision;
b) identify and coordinate ADWS procurement within and outside the service area(s) affected;
c) identify possible alternatives for water sourcing, conveyance, treatment and drinking water
distribution in cases of water contamination;
d) prepare logistical and engineering plans to implement the chosen approach(es) to provide the
quantity and quality of ADWS provision required;
e) identify the responders necessary to conduct field operations during a crisis and provide adequate
training and support to permit them to display readiness when required;
f) consider quantities and storage capacity for firefighting purposes, if applicable.
6 © ISO 2020 – All rights reserved

5.3 Securing resources and planning for their mobilization
Planning to secure and mobilize resources for ADWS provision should include the following:
a) Determining the area affected by the crisis within the service area(s): the drinking water utility
should determine the area(s) likely to be affected according to the individual circumstances of
the crisis.
b) Additional considerations such as variable weather conditions, the nature of the service area
(e.g. rural, urban), topographical features (e.g. estuaries, rivers, valleys, hills), the presence of
infrastructure (e.g. highways, railways, airfields, ports) and socio-economic considerations.
c) Operational and engineering plans for supplying water: the drinking water utility should organize
its drinking water system in a manner that permits as great a degree of flexibility and resilience
as is deemed practicable and cost-effective (e.g. installing additional valves and interconnections
beyond those essential for normal use; installing foundations, power supplies and pipework to
accept temporary pumping installations).
Such plans could include the distribution of non-drinking water if such provision mitigates risks
to public health or public safety (e.g. for toilet flushing or firefighting purposes). However, before
running drinking water again, the pipes should be flushed and residual chlorine should be checked
when appropriate to confirm that it is within the numerical standards.
d) Per-capita drinking water allocation(s): the drinking water utility should establish the per-capita
drinking water allocation(s) as a fundamental factor of ADWS planning. The per-capita drinking
water allocation(s) is particularly significant for ADWS methods where the normal drinking water
distribution network is not used. The per-capita drinking water allocation directly determines the
extent of resources (including personnel) needed for ADWS operations (see Annex C).
The drinking water utility should take into account the local legal or regulatory obligation for the
per-capita drinking water allocation(s) as well as for water quality. Where the resource implications
of addressing a worst-case disruption scenario put the ability to meet this obligation under strain,
this should be escalated to the drinking water utility's management. This issue could prompt
further discussion with the relevant authorities.
The drinking water utility should aim to balance users' expectations and the practicability of
providing a reasonable daily drinking water allocation.
NOTE A divergence between the legal or regulatory requirement for per-capita drinking water
allocation(s) and users' expectations of a minimum reasonable quantity is possible.
e) Planning TPDs: the drinking water utility should plan the locations and number of TPDs based on
the numbers and types of users and service areas.
f) Resources for the TPDs: the drinking water utility should plan the type and scope of resources
required for each TPD (e.g. containerized drinking water, personnel, vehicles, safety equipment).
Resources should be based on the relevant drinking water allocation(s) per capita and the numbers
of users that an individual TPD is designed to support.
g) Alternative water resources: in the case that alternative water resources are proposed, the drinking
water utility should plan and coordinate these – considering options both within and outside the
affected service area. Consideration should be given to:
1) periods when an alternative water resource could be unavailable due to inadequate water
quality and quantity (e.g. low source water level; algal bloom);
2) possible alternative(s) for conveyance, treatment and drinking water distribution by use of
a temporary waterworks (e.g. by utilizing portable treatment systems) which could make a
normally unusable water resource viable;
3) how a water tanker could be filled up from an alternative water resource.
h) ADWS provision: the drinking water utility should plan for adequate ADWS provision by developing:
1) a logistics plan for securing adequate supplies of containerized drinking water (see Annex D).
Where this involves provision of bottled water, the plan should include pre-coordination
with bottled water producers or suppliers. Such co-ordination could include contractual
arrangements for the supply of agreed quantities and product sizes. It could also include
arrangements for minimum stock levels (held by the supplier and/or the drinking water
utility) and the product's delivery to designated TPDs or intermediate storage destinations.
Such agreements should also specify timeframes for implementation including out-of-normal
working hours arrangements.
2) pre-coordination with other service providers to facilitate:
— transportation of ADWS resources to the TPDs;
— filling and replenishment of drinking water at the TPDs;
— collection and return of ADWS resources from the TPDs following recovery from the crisis.
3) informing stakeholders on ADWS provision, while addressing the differing needs of each type
of user.
4) pre-coordination with other third parties, for example:
— neighbouring and other drinking water utilities (if mutual aid arrangements can be agreed);
— military aid to the civil community (if such a protocol exists);
— other stakeholders from whom understanding, support and/or agreement to the ADWS
arrangements are essential for maintaining public confidence.
i) Internal and external communications: the drinking water utility should develop a communications
plan for internal and external communications during the deployment of an ADWS, which should
include:
1) The identification of responsibilities for coordination during a crisis, including ADWS provision,
deployment and replenishment; and identification of any operational issues that could require
escalation for tactical or strategic decisions. Those responsible for ADWS provision should
include updates about the effectiveness of those communications and the need to further tailor
them to enhance interactions between the drinking water utility and its stakeholders.
2) Guidance on how relevant issues and decisions are managed and then communicated to achieve
the desired outcomes.
3) Crisis management decision processes (e.g. internal communications; user communications;
stakeholder management) for framing and communicating relevant messages.
Guidance on ADWS communication issues is provided in Clause 7.
j) Users with special needs: guidance on ADWS provision for users with special needs is provided
in Clause 8 and Annex E. The drinking water utility should plan ADWS provision for users with
specials needs as follows:
1) during normal operations, by preliminary identification of such special needs;
2) during a crisis, by liaising with both internal and external stakeholders to ensure that any
dynamic supply adjustments to the requirements of users with special needs are captured and
incorporated into the ADWS response.
k) Responders: the drinking water utility should make the necessary personnel planning
arrangements for ADWS provision to be implemented. All relevant personnel should be trained
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periodically during normal operations. Training of any third parties anticipated to be involved in
ADWS provision should be undertaken – either at the request of the drinking water utility or as
other opportunities arise. Training should include practical exercises of all relevant personnel and
third parties.
6 Implementation of alternative drinking water service provision
6.1 General
The two approaches to ADWS provision outlined in 4.2 include various accepted ADWS implementation
methods. A drinking water utility's choice among these methods is likely to be governed by its preferred
approach – determined during the planning stage (see Clause 5).
For each crisis, subject to these pre-existing constraints, the drinking water utility should determine
the decision process for establishing which method(s) to use according to the:
a) circumstances of the crisis;
b) characteristics of the drinking water system specific to the service area(s) affected;
c) characteristics of the environment specific to the service area(s);
d) characteristics of the users; and
e) available resources (including personnel).
More than one implementation method can be used during a crisis.
6.2 Non-conventional methods for drinking water distribution network use
6.2.1 General
In this approach, water is supplied to users via the drinking water distribution network, but not in the
normal operational manner. Sometimes the service level can be of a lower standard than during normal
service provision.
6.2.2 Distribution of drinking water by erection of standpipes
Where water quality is maintained but water quantity is constrained by the crisis, the drinking water
utility can operate ADWS provision by erecting temporary standpipes connected to the drinking water
distribution network. Such a method can create control issues with regards to the assets (e.g. the
standpipes themselves and the hydrants on which they are mounted), the quantities of water discharged
and the resulting flow disturbances in the drinking water distribution network. Deployment of this
method depends on the drinking water utility’s resources to manage the operation of the assets and
can be affected by the degree of cooperation anticipated from users.
6.2.3 Recharging of isolated drinking water distribution network assets by water tankers
According to circumstances and the event characteristics (e.g. treatment plant failure; aqueduct failure),
the drinking water utility can use mobile tankers to recharge drinking water system storage assets,
such as reservoirs, or the drinking water distribution network itself (by pumped or gravity feed). This
action can enable continued drinking water supply to users through the drinking water distribution
network.
This method can require relevant authorities' approval, is dependent on sustained recharge of the
drinking water distribution network and carries an increased risk of contaminating the network.
6.2.4 Lowering the pressure at which drinking water is supplied
Drinking water should be supplied through the normal drinking water distribution network, at lower
pressure than normal, by controlling valves and other water assets in accordance with circumstances
and engineering constraints. This method can require relevant authorities' approval of a minimum
sustained pressure in the drinking water distribution network.
6.3 Methods not using the drinking water distribution network
6.3.1 General
In this approach, TPDs should be established by trained personnel across the service area(s) affected by
the crisis. The drinking water utility should advise able-bodied users to independently approach a TPD
to get drinking water according to their determined drinking water allocation. Different arrangements
should be made for users with special needs (Clause 8). Users should be advised of TPDs locations
within close proximity to their residence or workplace or where they can legitimately claim a need.
A drinking water utility representative should be present to assist users (where resources and/or the
number and configuration of TPDs permit).
TPDs should be locat
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