ISO/TC 224 - Drinking water, wastewater and stormwater systems and services

This document provides guidance and requirements for identifying and assessing impacts of climate change on drinking water systems and for developing strategies for the adaptation to these impacts. The assessment of the impacts is based on the assessment principles described in ISO 24566-1. This document also provides examples of some of the impacts of climate change on drinking water systems and of the responses that have been implemented by municipal water services or by the relevant jurisdiction (e.g. municipality or region served by the service). The examples of responses illustrate adaptation strategies that have been applied.

The document provides guidelines for the management of electrically powered mobile toilets that are connected to water and electricity under public epidemic emergencies (PEEs) from different perspectives, including users, operators, and suppliers. It also gives recommendations to provide safe sanitation services for users, cleaners, and waste tank drivers. It is applicable to epidemic situations of major respiratory tract and intestinal infectious diseases, but not to group unexplained diseases, major food and occupational poisoning and other events that seriously affect public health.

This document provides guidance and requirements for identifying and assessing impacts of climate change on wastewater systems and on developing strategies for the adaptation to these impacts. The assessment of the impacts is based on the assessment principles described in ISO 24566-1. This document also provides examples of some of the impacts of climate change on wastewater systems and of the responses that have been implemented by municipal water services or by the relevant jurisdiction (e.g. municipality or region served by the service). The examples of responses illustrate adaptation strategies that have been applied. NOTE Both combined and non-combined wastewater systems are included in this document regarding the activities of collection, transport, storage and treatment of wastewater.

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.

This document provides guidance and requirements for the management of on-site domestic wastewater systems and services, using appropriate technologies in their entirety at any level of development. This document supplements and is intended to be used in conjunction with ISO 24511 and ISO 24525. It includes guidance and requirements for the following: — management of on-site domestic wastewater systems and services from the operator’s perspective, including maintenance techniques, training of personnel and risk considerations; — management of on-site domestic wastewater systems (ODWS) from the perspective of owners and users; — design and construction of ODWS; — planning, operation and maintenance, and health and safety issues. This document is applicable to both publicly and privately operated on-site domestic wastewater (black and grey water) services, for one or more dwellings. In rural areas and areas under development, management is sometimes provided by the owners of the premises where wastewater is generated. In this document the term “services” includes “self-services” provided by the owners of the premises. The following are outside the scope of this document: — limits of effluent quality for wastewater discharged into the environment; — analytical methods; — stormwater runoff; — content of contracts or subcontracts.

This document contains selected examples for good practice approaches for the management of assets of drinking water supply systems. This document is intended as a supporting document for ISO 24516-1 and ISO 24516-2, which contain guidelines for the management of assets of drinking water systems. As such, this document can contribute to realize value from existing assets when following the guidelines for the management of assets of drinking water systems approaches in the strategic, tactical, and operational plans given in ISO 24516-1 and ISO 24516-2. NOTE A recapitulative table of the examples covered in this document is provided in Annex A.

This document provides guidance on identifying and assessing the impacts of climate change on stormwater systems and on developing strategies for adapting to these impacts. The assessment of the impacts is based on the assessment principles described in ISO 24566-1. This document also provides examples of some of the impacts of climate change on stormwater systems and of the responses that have been implemented by municipal water services or by the relevant jurisdiction (e.g. municipality or region served by the service). The examples of responses illustrate adaptation strategies that have been applied. NOTE Combined sewer systems are included in this document in relation to the activities of collection, transport, storage and treatment of stormwater. Non-combined wastewater systems are covered by ISO 24566-4.

This document provides a general foundation for data management in services, systems and facilities related to drinking water, wastewater and stormwater. It emphasizes data as an asset and introduces basic rules for efficient data acquisition, storage and processing. It aims to help water system owners and operators manage water facilities more efficiently based on large-scale data. The following aspects are within the scope of this document: — management of data as an asset in water systems; — data management principles and guidelines; — people organization in relation to data management.

This document provides guidelines for the management of drinking water utilities and the assessment of drinking water services. This document is applicable to publicly and privately owned and operated water utilities. It does not favour any particular ownership or operating model. This document addresses drinking water systems in their entirety and is applicable to systems at any level of development (e.g. on-site systems, distribution networks, treatment facilities). The following are within the scope of this document: — the definition of a language common to different stakeholders; — the definition of the components of drinking water supply systems; — guidelines for the management of drinking water utilities; — guidelines for objectives, service assessment criteria and related performance indicators, appropriate for the assessment of drinking water services. The following are outside the scope of this document: — target values and thresholds for proposed objectives, service assessments criteria and related performance indicators; — matters relating to the design and construction of drinking water systems; — matters relating to the management structure of drinking water utilities; — matters relating to the regulation of drinking water services, including management and operational activities; — matters relating to regulating the content of contracts or subcontracts; — installations between point of delivery and point of use.

This document provides guidelines for the management of wastewater utilities and the assessment of wastewater services. This document is applicable to publicly and privately owned and operated wastewater utilities but does not favour any particular ownership or operational model. NOTE 1 Wastewater is always generated when water is used or consumed. Accordingly, sources of wastewater can be residential, industrial, commercial or institutional. Collected storm water or (melted) snow can also be considered as wastewater, as it often carries contaminants and pathogens picked up from air or ground surfaces on its way to a collection system. In certain circumstances, especially in undeveloped areas, sanitary waste is collected in an undiluted form. This document addresses wastewater systems in their entirety and is applicable to systems at any level of development (e.g. pit latrines, on-site systems, networks, treatment facilities). The following are within the scope of this document: — the definition of a language common to different stakeholders; — objectives for the wastewater utility; — guidelines for the management of wastewater utilities; — service assessment criteria and related examples of performance indicators, all without setting any target values or thresholds. The following are outside the scope of this document: — methods of design and construction of wastewater systems; — regulation of the management structure and the methodology of wastewater service activities of operation and management; — regulation of the content of contracts or subcontracts; — topics related to the systems inside buildings, between the point-of-discharge and the point-of-collection.

This document provides guidelines for the planning and implementation of hardening of different water and wastewater infrastructures aiming to improve the resilience of water and wastewater services provided by water utilities through security measures. It applies to the determination of measures for the protection of water supply systems and sewer collection systems from unwanted or unplanned access, as part of risk management. This document is applicable to all water and/or wastewater utilities. This document does not include guidelines for the protection of large water sources such as lakes or rivers.

This document specifies the elements of drinking water and wastewater services of relevance and interest to users. It also provides guidance on how to identify users’ needs and expectations and how to assess whether these are being met. The following are within the scope of this document: — the definition of a language common to the different stakeholders; — the definition of key elements and characteristics of the service to users; — the objectives for the service with respect to users’ needs and expectations; — guidelines for satisfying users’ needs and expectations; — assessment criteria for service to users; — introduction to performance indicators; — examples of performance indicators. The following are outside the scope of this document: — methods of design and construction of drinking water and wastewater systems; — the regulating management structure and methodology of operation and management of activities relating to drinking water and wastewater services, including contracting; — topics relating to the system inside buildings.

This document provides guidelines for alternative water service (AWS) provision during a crisis for the ongoing operation of essential facilities. This document addresses: — AWS principles and methods; — AWS operational planning and implementation. This document is not applicable to: — planned water supply interruptions forming part of the drinking water utility's normal operations; NOTE However, many of the principles and methods described can be appropriate in such circumstances. — water supplied to temporary settlements, such as refugee camps; — the development and implementation of a crisis management system for water service, which is covered by ISO 24518[1] and ISO/TS 24520,[2] or the development and implementation of AWS provision during a crisis for private users, which is covered by ISO 24527.[3]

This document provides principles and guidelines for smart water management relating to drinking water, wastewater, stormwater systems and services. The following are within the scope of this document: — principles and guidelines for design of smart water management system; — principles and guidelines for operation and maintenance of smart water management systems; — principles and guidelines for governance of smart water management system. This document applies to all sizes of public or private water utilities that want to design, develop, implement, operate and/or maintain smart water management systems.

This document identifies and sets out principles for integrating climate change impacts into the planning and design activities of water utilities for the provision of water services. It also includes methodologies to assess the principles in the context of climate change and to provide examples of adaptations made. NOTE Discussion of impacts and strategies for responses for stormwater, drinking water and wastewater utilities are intended to be set out in ISO 24566-2:—[1], ISO 24566-3:—[2] and ISO 24566-4:—[3], respectively, with examples of adaptations that have been made. [1] Under preparation. Stage at the time of publication: ISO/DIS 24566-2:2023. [2] Under preparation. Stage at the time of publication: ISO/CD 24566-3:2023. [3] Under preparation. Stage at the time of publication: ISO/CD 24566-4:2023.

This document establishes the basis for a framework for water utilities to operate efficiently and effectively considering stakeholder needs and expectations. This document is applicable to all water utilities, regardless of ownership and management model (public or private), size, service provided or location. This document proposes principles for effective and efficient corporate governance of water utilities with a focus on the roles and responsibilities of the responsible bodies and operators and on the decision-making process involving the relevant stakeholders. It also includes key types of decisions to be made.

This document provides guidance and specifications for the operation and maintenance (O&M) of on-site domestic wastewater services, using appropriate technologies at any level of development. This document supplements and is intended to be used in conjunction with ISO 24513 and ISO 24521. This document provides assistance to relevant authorities, training organizations, certification bodies and other responsible entities for the development of regulations, plans and manuals, as well as information and training materials addressed to operators and users of on-site domestic wastewater systems (ODWS). This document is applicable to both publicly and privately operated on-site domestic wastewater (blackwater and greywater) systems for one or more dwellings or other premises where wastewater is generated. The scope of this document includes the following: — O&M of ODWS from the operator’s perspective; — O&M of ODWS from the user’s perspective; — training and information aspects; — environmental, health and safety issues. The following are outside the scope of this document: — detailed design of ODWS; — limits of acceptability for discharge of wastewater or sludge; — analytical methods; — management structure of wastewater services’ activities for O&M; — content of contracts or subcontracts. NOTE 1 Management of ODWS, especially in rural areas and areas under development, is sometimes provided by the owners of the premises where wastewater is generated. In such cases, the owners of the premises carry out the management themselves. In this document, the term “services” includes “self-services” provided by the owners or users of the premises. NOTE 2 Especially in undeveloped areas, sanitary wastewater is collected in an undiluted form. Sources of sanitary wastewater in this document are domestic, excluding stormwater runoff. NOTE 3 The designation of activities as operation activities or maintenance activities can differ according to the local context. However, it is important that activities essential for the proper functioning of ODWS are carried out, no matter how these activities are designated.

This document provides guidelines for alternative water services (AWS) and alternative wastewater services (AWWS) to temporary settlements for displaced persons e.g. refugee/internally displaced persons (IDP) camps, for drinking, sanitation and hygiene purposes. It addresses AWS and AWWS principles and methods, operational planning and implementation. This document provides guidelines for drinking water supply to temporary settlements, and the disposal of wastewater, by implementation of different methods; it does not deal with the ways of using water inside the temporary settlements. This document deals with drinking water quantity but does not provide methods for quality testing. Water quality test methods are included in the scope of ISO TC 147. The document does make recommendations regarding public safety with respect to the location of distribution and collection points. On-site treatments are not discussed in this document but, depending on circumstances, they can be suitable. In such case, helpful technical guidelines are provided in the bibliography of this document. This document complements ISO 24527, whose scope excludes drinking water supplied to temporary settlements. It also complements other ISO TC 224's documents such as ISO 24518 and ISO/TS 24520. This document is intended to be used by the responsible body for the provision of the water service. It can be used by interested parties such as water utilities, governments and governmental organizations, security bodies, international refugee agencies, related NGOs and relevant industry stakeholders.

This document provides examples of good practices in stormwater management related to ISO 24536 and information on standards and guidelines used in various countries.

This document provides a methodology for undertaking a water loss investigation and establishing general principles for water loss management in drinking water distribution networks in order to improve the sustainability of drinking water utilities and protect the environment by saving water, energy and use of chemicals. This document establishes a procedure to estimate water loss components through water balance calculations and to define general principles of water loss management. This document deals with the preparation of a water loss management plan for water loss reduction and management projects but does not cover its execution. This document does not cover bulk drinking water supply systems, but can relate to pumping, storage and transmission within the drinking water distribution network. This document can be used analogously for non-public supply systems, raw water and industrial water systems. This document is intended for drinking water utilities and other stakeholders.

This document specifies guidelines for the implementation of continuous monitoring systems for drinking water quality and operational parameters in drinking water distribution networks. It provides guidance for determining the: — effective number of continuous monitoring stations in the drinking water distribution network; — location of monitoring stations in the drinking water distribution network; — types of operational and drinking water quality parameter measuring devices (MDs) that can be installed in a continuous monitoring station; — quality control, maintenance and calibration requirements of the continuous monitoring system. This document excludes guidance on the design, structure, number and type of MDs to be installed in a continuous monitoring system.

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.

This document provides guidance to stormwater management authorities and relevant stakeholders on both structural and non-structural stormwater management approaches. The guidance includes consideration of relevant policies, planning, design criteria and implementation processes for stormwater management, and performance evaluation. This document can be applied to new stormwater systems and to the extension or improvement of existing systems for both fully separated and combined storm and sanitary sewers. This document is applicable to stormwater sewer systems as well as combined sewer systems. This document is not applicable to sanitary sewer systems.

This document specifies requirements and contains guidance for its use in establishing, implementing and maintaining a water efficiency management system. It is applicable to organizations of all types and sizes that use water. It is focused on end-use consumers. This document is applicable to any organization that wishes to: a) achieve the efficient use of water through the ?reduce, replace or reuse' approach; b) establish, implement and maintain water efficiency; c) continually improve water efficiency. This document specifies requirements and contains guidance for its use regarding organizational water use. It includes monitoring, measurement, documentation, reporting, design and procurement practices for equipment, systems, processes and personnel training that contribute to water efficiency management. NOTE 1 ?Reduce' includes the use of water-efficient fittings and equipment and, for example, putting in place a proper monitoring system for usage and leak detection. NOTE 2 ?Replace' includes substitution of drinking water with reclaimed water, sea water and rainwater wherever feasible. NOTE 3 ?Reuse' includes recycling of, for example, process water or grey water. For utilizing water reuse systems, ISO/TC 282 documents can be referred to as guidelines. NOTE 4 Guidance in the annexes provides additional practical information to support implementation. Annex A provides guidance on the use of this document and Annex B gives examples of scenarios in water efficiency.

This document specifies guidelines for technical aspects, tools and good practices for the management of assets of waterworks to maintain value from existing assets. This document includes the following asset types: treatment plants, sludge treatment facilities, pumping stations, reservoirs, tanks and dosing equipment, metering and ancillary infrastructure irrespective of where they are sited, in the waterworks or in the drinking water distribution network. For further guidance on drinking water distribution networks see ISO 24516-1. NOTE 1 The management of transmission mains is addressed in ISO 24516-1 irrespective of where these assets are sited in the drinking water system. This document is focused on the assets typically owned or operated by drinking water utilities (drinking water systems) that in parts are expected to meet users' needs and expectations over longer (multi-generational) periods. This document includes examples of good practice approaches on the strategic, tactical and operational levels. This document is applicable to all types and sizes of organization and/or utilities operating drinking water systems. NOTE 2 Depending on the size and structure of an organization, the utility can decide to what extent it applies the guidance in this document. In any case, the philosophy of this document remains applicable even to small and medium utilities. NOTE 3 This includes all different roles/functions for the management of assets within a utility (e.g. asset owner/responsible body, asset manager/operator, service provider/operator).

This document specifies guidelines for technical aspects, tools and good practices for the management of assets of wastewater treatment plants, sludge treatment facilities, pumping stations, and retention and detention facilities in the wastewater system to maintain the value of existing assets. NOTE 1 For simplicity in reading this document, reference to wastewater treatment plants includes all the asset types described above. For further guidance on wastewater networks see ISO 24516-3. NOTE 2 For simplicity of interpretation of wastewater system assets, the management of pumping stations and retention and detention facilities in the network, excluded from ISO 24516-3, is addressed in this document irrespective of where these assets are sited in the wastewater system. This document is focused on the assets in wastewater systems typically owned or operated by wastewater utilities that are expected to meet users' needs and expectations over longer, sometimes multi-generational, periods. This document includes examples of good practice approaches on the strategic, tactical and operational levels. This document is applicable to all types and sizes of organizations and/or utilities operating wastewater systems. NOTE 3 Depending on the size and structure of an organization, the utility can decide to what extent it applies the guidance in this document. In any case, the philosophy of this document remains applicable even to small and medium utilities. NOTE 4 This includes all different roles/functions for the management of assets within a utility (e.g. asset owner/responsible body, asset manager/operator, service provider/operator).

This document defines individual concepts that together constitute a vocabulary common to different stakeholders with interests in water service provision. It is intended to facilitate common understanding and communication on the provision and management of service activities relating to drinking water supply, wastewater and stormwater systems. The following are within the scope of this document: — definition of a vocabulary common to the different stakeholders; — definition of key elements and characteristics of the service to users; — definition of the components of drinking water supply, wastewater and stormwater systems.

This document provides guidance for water utilities on the detection and classification of water and wastewater events. The following subjects are within the scope of this document: — publicly and privately owned and operated water utilities. It does not favour any particular ownership or operating model; — all aspects of the drinking water system and the wastewater system; — all causes of abnormal changes in water and/or wastewater service provision capable of detection by monitoring systems including accidents, unexpected operational changes, natural hazards and intentional disruption. This document is independent of the measurement methods used to collect the data. The document focuses on events which could imminently affect the water utility's interested parties. The following are outside the scope of this document: — methods of design and construction of drinking water and wastewater systems; — plumbing and drainage systems not under the control of the water utility. This document does not include details about action taken as a result of event detection. For such details see ISO 24518 and EN 15975 Part 1.

ISO/TR 24524:2019 details the hydraulic, mechanical and environmental conditions generally found in wastewater transport systems from toilets through to wastewater treatment plants, the general powers of wastewater services to manage discharges to sewers, and the responsibilities imposed on wastewater services by applicable local, regional or national legislation.

This document provides several examples of varying complexity which illustrate the use and intent of the performance assessment methodology set out in ISO 24510, ISO 24511 and ISO 24512. The document also provides examples of the parallel and similar practices for measuring performance or establishing benchmarks as found in various institutional circumstances. These examples represent practices in a range of utilities (e.g. small, medium and large water utilities; water utilities from developed and developing countries; water utilities in both the public and private sectors; government and non-governmental agencies; and utilities with and without certified management systems). They are drawn from many geographical locations.

ISO/TS 24520:2017 provides guidance to water utilities on good practice in technical aspects of crisis management. ISO/TS 24520:2017 is applicable to all water utilities, of whatever size, whether public or private, that wish to review the effectiveness and efficiency of their service activities relating to preparation for, response to and recovery from a crisis.

ISO 24516-3:2017 specifies guidelines for technical aspects, tools and good practices for the management of assets of wastewater networks to maintain value from existing assets. ISO 24516-3:2017 does not apply to the management of assets of treatment plants, which are also physically part of the wastewater system and can influence the management of network assets. NOTE 1 The management of the following individual assets will be covered by ISO 24516‑4: wastewater pumping stations, retention and detention in the network, wastewater treatment plants and sludge treatment facilities. ISO 24516-3:2017 includes examples of good practice approaches on the strategic, tactical and operational levels. ISO 24516-3:2017 is applicable to all types and sizes of organizations and/or utilities operating wastewater networks, and all different roles/functions for the management of assets within a utility (e.g. asset owner/responsible body, asset manager/operator, service provider/operator). NOTE 2 Depending on the size and structure of an organization, the utility can decide to what extent it applies the guidance in this document, but in any case, the philosophy of this document remains applicable to small and medium utilities.

ISO 24523:2017 provides guidelines on good benchmarking practice of drinking water and wastewater utilities. It describes the basic framework and methods associated with benchmarking in the water sector. The guidelines are intended primarily for voluntary benchmarking. Specific objectives set forth by the authorities and which are to be achieved by the water utility are not covered by this document. ISO 24523:2017 is applicable to water utilities of any size managed by a public or private entity. It does not favour any particular ownership or operating model.

ISO 24516-1:2016 specifies guidelines for technical aspects, tools and good practices for the management of assets of drinking water networks to maintain value from existing assets. ISO 24516-1:2016 does not apply to the management of assets of waterworks (including catchment and treatment, pumping and storage in the network), which are also physically part of the drinking water system and can influence the management of assets of the pipe network. ISO 24516-1:2016 focuses on the assets typically owned or operated by drinking water utilities (networked drinking water systems) that are expected to meet customer needs and expectations over longer (multi-generational) periods. ISO 24516-1:2016 includes examples for good practice approaches on the strategic, tactical and operational levels. ISO 24516-1:2016 is applicable to all types and sizes of organization and/or utilities operating drinking water systems, and all different roles/functions for the management of assets within a utility (e.g. asset owner/responsible body, asset manager/operator, service provider/operator).

ISO 24521:2016 provides guidance for the management of basic on-site domestic wastewater services, using appropriate technologies in their entirety at any level of development. ISO 24521:2016 supplements and is intended to be used in conjunction with ISO 24511. It includes the following: · guidelines for the management of basic on-site domestic wastewater services from the operator's perspective, including maintenance techniques, training of personnel and risk considerations; · guidelines for the management of basic on-site domestic wastewater services from the perspective of users; · guidance on the design and construction of basic on-site domestic wastewater systems; · guidance on planning, operation and maintenance, and health and safety issues. The following are outside the scope of ISO 24521:2016: · limits of acceptability for wastewater discharged into a receiving body; · analytical methods; · the management structure of sanitary waste/wastewater service activities of operation and management; · the content of contracts or subcontracts. ISO 24521:2016 is applicable to both publicly and privately operated basic on-site domestic wastewater (black and grey water) services, for one or more dwellings.

ISO 24518:2015 provides general guidance to water utilities to develop and implement a crisis management system. ISO 24518:2015 may be applicable to all sizes of public or private water utilities that want to prepare, respond, and recover from a crisis.

This document covers the methodology for initiating a master plan for water supply and establishing general principles for considering relevant data of existing and future systems.

IWA 6:2008 is intended to identify and chart the critical elements that are of great significance to drinking water security. Its purpose is to set in motion a continuous process for the establishment of guidelines on management systems for drinking water utilities under crisis conditions. IWA 6:2008 provides the guidelines for a water utility, or any body responsible for the management of parts of the water supply system, to be prepared and ready to manage a water crisis. It also provides a roadmap for possible relevant International Standards that could be useful and could be developed.

ISO 24510:2007 specifies the elements of drinking water and wastewater services of relevance and interest to users. It also provides guidance on how to identify users' needs and expectations and how to assess whether they are being met. The following are within the scope of ISO 24510:2007: the definition of a language common to the different stakeholders; the definition of key elements and characteristics of the service to users; the objectives for the service with respect to users' needs and expectations; guidelines for satisfying users' needs and expectations; service to users assessment criteria; introduction to performance indicators; examples of performance indicators.

ISO 24512:2007 provides guidelines for the management of drinking water utilities and for the assessment of drinking water services. ISO 24512:2007 is applicable to publicly and privately owned and operated water utilities. It does not favour any particular ownership or operating model. ISO 24512:2007 addresses drinking water systems in their entirety and is applicable to systems at any level of development (e.g. on-site systems, distribution networks, treatment facilities). The following are within the scope of ISO 24512:2007: the definition of a language common to different stakeholders; the definition of the components of drinking water supply systems; guidelines for the management of drinking water utilities; guidelines for objectives, service assessment criteria and related performance indicators, appropriate for the assessment of drinking water services.

ISO 24511:2007 provides guidelines for the management of wastewater utilities and for the assessment of wastewater services. ISO 24511:2007 is applicable to publicly and privately owned and operated wastewater utilities, but does not favour any particular ownership or operational model. ISO 24511:2007 addresses wastewater systems in their entirety and is applicable to systems at any level of development (e.g. pit latrines, on-site systems, networks, treatment facilities). The following are within the scope of ISO 24511:2007: the definition of a language common to different stakeholders; objectives for the wastewater utility; guidelines for the management of wastewater utilities; service assessment criteria and related examples of performance indicators, all without setting any target values or thresholds.