3.1 Introduction to a Water Demand Management Plan

WDM policies and interventions are proposed, legislated, regulated, and implemented by various stakeholders,Footnote 1 depending on a country, province, or city’s context. Although federal and/or local authorities often propose WDM interventions in the form of strategies, master plans, and legislations, measures are often implemented by the water service providers, particularly in urban contexts (Barsugli et al. 2012; Liner and DeMonsabert 2011).

WDM plan formats may vary from one city to another, depending on the governance system, water service providers, and existing water supply provisions. Developing a fit-to-context WDM plan can help inform water service providers how to achieve efficient water use and encourage water conservation, optimising existing resources before considering the creation of additional resources and infrastructure (Maples et al. 2014; US EERE n.d.; Wang et al. 2020).

It is recommended that water service providers have a clear and well-structured WDM plan that succinctly outlines the design response to managing water demand with clarity. The plan may give consideration to analyses, programmes, policies, and also measures of WDM, along with clear definitions of the following: (1) objectives/targets (short, medium, and long term); (2) approach/process; (3) budget; and (4) time frames of implementation (IUCN 2016; Hoffman and Plessis n.d.).

  1. 1.

    Objectives/Targets: Measurable objectives/targets should be set based on the existing water situation in a given context (i.e. supply–demand) and realistic estimates of what can be achieved through the proposed measures, while avoiding conflicting objectives (China Water 2010; IUCN 2016; Mohammad-Azari et al. 2021; Xiao et al. 2018).

  2. 2.

    Approach/Process: The WDM plan may include suggestions on the planning approach through a detailed and transparent decision-making process, with clear roles and responsibilities, which can be adapted to varying conditions (EPA 2016).

  3. 3.

    Budget: Adopters may identify the financing arrangement for WDM measures with associated costs on a time frame consistent with the available budget. WDM measures can be evaluated on a cost-effectiveness basis and prioritised based on the greatest potential benefit for the least capital investment (Hoffman and Plessis n.d.; Pacific Water n.d.) or measures that secure significant water savings (refer to Sect. 3.4 of this report).

  4. 4.

    Time Frames of Implementation: Measurable targets may be determined based on established time frames of implementation that are realistic (Hoffman and Plessis n.d.) and that prioritise relevant measures, address immediate needs, and track the progress of implementations (CSE 2017).

3.2 Notable Example of a Water Demand Management Plan: PUB, National Water Agency of Singapore

Singapore’s water supply, water catchment, and used water are managed by the Public Utilities Board (PUB), its national water agency (PUB 2021a, b). Presently, Singapore is internationally recognised as a model city for integrated water management, with expertise in water management technologies (PUB n.d.). Forward planning has played a key role in developing Singapore’s water infrastructure, where planning instruments such as the 1971 Concept PlanFootnote 2 and the 1972 Water Master PlanFootnote 3 have set the foundation for long-term water strategies (Tortajada et al. 2013). Through the years, PUB has formulated long-term plans, implemented them promptly, and embarked on an integrated approach to water management, focusing on three key strategies:

  • Collect every drop of water.

  • Reuse water endlessly.

  • Desalinate seawater (PUB n.d.).

Over the years, PUB has directed attention to the growing water demand to ensure that water demand does not rise at an unsustainable rate. Thus, planning has incorporated WDM measures with clearly defined targets, outcomes, and timelines for implementation. This is illustrated in Table 3.1.

Table 3.1 PUB water demand management planning
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To achieve the above, PUB has adopted a multi-pronged approach with several predetermined WDM measures. A summary can be seen in Table 3.2.

Table 3.2 Summary of water demand management measures in Singapore
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Singapore’s success in water management is grounded in its comprehensive planning systems, where water has been integrated into the city-state’s overall development plans, including urban development (Lafforgue and Lenouvel 2015; Tortajada et al. 2013). Through the years, PUB has formulated long-term plans, with clearly defined targets that have been implemented on a timely basis. Quantifiable targets have been set based on the existing water situation and realistic estimates of what can be achieved through the proposed measures (Chen et al. 2011; Lafforgue and Lenouvel 2015).

3.3 Steps to Developing a Water Demand Management Plan

By developing a strategic and comprehensive WDM plan, water service providers can set out specific water-use reduction targets to achieve water conservation goals and seek greater water efficiency through defined targets (CDWR n.d.; EPA 2015; Kiefer and Krentz 2018; US EERE n.d.).

In general, developing a WDM plan involves the following steps:

  • Situation analysis. Reviewing existing policies, regulations, water trends, flows, and demands through data collection and analysis.

  • Identifying water management constraints and opportunities. Evaluating the implementation of existing WDM measures and identifying applicable WDM measures where options may be prioritised based on costs, water-saving potential, social acceptance levels, and impact on the water supply–demand balance.

  • Undertaking economic analyses of WDM options through various methods, such as cost–benefit analysisFootnote 8 and multi-criteria analysis.Footnote 9

  • Setting WDM objectives/targets: clear quantitative indicators to measure performance and progress. Possible indicators may include

    • Rate of non-revenue water (NRW).

    • Levels of metering.

    • Unit operations and maintenance costs.

    • Total water consumption.

    • Trends in leakage reduction.

    • Percentage of cost recovery.

  • Selecting and prioritising WDM options: screening measures for applicability, feasibility, and acceptability.

  • Developing the WDM plan.

Sources CSE (2017), IUCN (2016), Pacific Water (n.d.), US EERE (n.d.).

As discussed, WDM plan formats may differ from one city to another, depending on the governance system, water service providers, and existing water supply provisions. Thus, the steps to developing a WDM plan may also vary based on the governance and water provision context. Table 3.3 provides an overview of selected guidelines to develop a WDM plan for implementation in countries, such as India, France, South Africa, and the USA.

Table 3.3 Overview of selected guidelines to water demand management planning
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3.4 Notable Example of Water Demand Management Planning

Figure 3.1 highlights a phased, nine-stage approach for a WDM strategy, starting with the collection and verification of data and culminating in the implementation and evaluation of the effectiveness of strategies in place (Pacific Water n.d.).

Fig. 3.1
A flow diagram includes 9 phases. 1. Collect and verify data. 2. Undertake water system audit. 3. Undertake water supply end use analysis. 4. Review water costs. 5. Identify appropriate demand management options. 6. Undertake economic analysis of options. 7. Develop demand management strategies and action plans. 8. Implement strategies. 9. Evaluate effectiveness of strategies.

Source Pacific Water (n.d.)

Water demand management process.

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The guideline is developed by the Pacific Community, an international development organisation that generates research on topics such as water, sanitation, and fisheries science (Pacific Water n.d.). It serves as a support tool for local water service providers, practitioners, and consultants involved in developing and implementing WDM plans. The nine-stage approach demonstrates how water service providers can develop and implement a feasible WDM plan to achieve WDM targets through a step-by-step method. It provides a comprehensive and integrated approach to WDM planning that has been developed for implementation in water-scarce countries such as AustraliaFootnote 11 (Pacific Water n.d.). In addition, this considers several aspects of relevance to water service providers for WDM planning and implementation, such as system audits, end-use analyses, and economic assessments. This example also acknowledges the valuable role of broad stakeholder participation in providing feedback to water service providers in the WDM planning and implementation process.

The water demand management process involves the following:

Phase 1: Collect and verify data to identify critical constraints and opportunities. This can include collating information related to

  1. (a)

    Bulk meter readings within the water network.

  2. (b)

    Wastewater flows and assessments.

  3. (c)

    Rainfall estimates.

  4. (d)

    Prior information on leakages within the network.

  5. (e)

    Daily flow trends of the water system.

  6. (f)

    Existing information gaps.

Phase 2: Undertake a water system audit. This would help assess all water flows within the system. As a water audit can track water loss by identifying and quantifying potential leaks, it may be followed by a meter testing and calibration programme. Water service providers may also undertake customer and operational investigations for potential leaks or unauthorised consumption (theft) to prevent (further) loss of revenue ( EPA 2015; Pacific Water n.d.;Van Arsdel 2021). A preliminary top-downFootnote 12 water audit may be conducted as follows:

  1. (a)

    Identify the amount of water added to the system (typically for one year).

  2. (b)

    Identify authorised water consumption (billed + unbilled water).

  3. (c)

    Calculate water losses (water losses = system input − authorised consumption) (CSE 2017; EPA 2015).

Phase 3: Undertake a water supply end-use analysis. This may include the following:

  1. (a)

    Identifying customer use profiles and water usage patterns.

  2. (b)

    Identifying customer water demand trends (i.e. number of connections versus consumption range) (Pacific Water n.d.; US EERE n.d.).

Phase 4: Review operational and maintenance-related costs (Pacific Water n.d.; US EERE n.d.)

Phase 5: Identify appropriate water demand management options by selecting and prioritising options based on measure applicability, feasibility, and acceptability (CSE 2017; McDonald and Mitchell 2019; Rathnayaka et al. 2016; Victoria State Government 2021). The appropriate amount of water demand measures may vary, depending on the governance structure, level of development, and the degree of water scarcity in each city (Global Water Partnership 2012).

Options may be prioritised according to their (a) water-saving potential; (b) social acceptance; and/or (c) impact on the supply–demand balance.

  1. (a)

    Water-saving potential refers to the total amount of water saved by different water user groups, which may vary considerably in accordance with the WDM measure in question (Pacific Water n.d.; Wang et al. 2020). To determine the water-saving potential of a given WDM measure, a prioritisation analysis of WDM measures can be undertaken by governments and/or water service providers to determine and select the most sustainable WDM options (Bello-Dambatta et al. 2013; Rathnayaka et al. 2016).

  2. (b)

    Social acceptance refers to a collective consensus of stakeholders and institutional feasibility for the implementation of WDM measures (Butler and Memon 2006). It includes the impacts on society through public perception, politicisation, individual acceptance, and use adaptation (Al-Saidi 2021; Rathnayaka et al. 2016). Despite some WDM measures being more socially acceptable than others, an absolute level of social acceptance for each WDM measure has not been established (CSIRO 2010).

    Effective public education and awareness campaigns, such as public communications through the media (Tortajada and Nambiar 2019), as well as social norms,Footnote 13 can influence the social acceptance and public opinion of WDM measures (Lede and Meleady 2018). The social acceptability of WDM measures may also increase when there is a need to reduce water use, such as in times of drought (Bello-Dambatta et al. 2013).

  3. (c)

    Impact on the supply–demand balance refers to the influence that WDM measures can have on the supply of and demand for water. The current supply and demand of water is influenced by the availability of freshwater and impacts of climate change (Gosling and Arnell 2016; Lede and Meleady 2018). This includes extreme hydrologic events such as droughts, floods, typhoons, and cyclones that create uncertainties about traditional sources of water supply (e.g. freshwater), (Bello-Dambatta et al. 2013; Bloetscher et al. 2014; Xiao et al. 2016).

    At the same time, urbanisation, rapid population growth, and competing water uses (domestic, commercial, and industrial) also affect water demand (Chen and Trias 2020; Cousin et al. 2019; Hartley et al. 2019; Subramanian 2019). Identifying and assessing the potential impact of these influences over the existing supply–demand balance can enhance the decision-making process (Smart Water Fund 2011).

    To maintain the water supply–demand balance and safeguard the security of future water supply, an array of WDM measures can be implemented. As different WDM measures will have different impacts on the supply–demand balance, governments and water service providers can assess and determine which WDM measures are appropriate for certain areas as well as which WDM measures will improve the water supply–demand balance (Rathnayaka et al. 2016; Victoria State Government 2021). If it is deemed that water demand must be reduced, then other factors, such as cost-effectiveness, may need to be adjusted accordingly to facilitate this (Bello-Dambatta et al. 2013).

Phase 6: Undertake an economic analysis of options.

Reliable estimates of water consumption and operational costs are necessary to evaluate this consideration. An economic analysis of options can be undertaken to guide the prioritisation of options. The chosen approach to an analysis of this kind should be bespoke to the initiative being considered (CSE 2017; Pacific Water n.d.; Victoria State Government 2021).

  1. (a)

    Cost–benefit analysis (CBA). CBA is the most widely recognised economic tool by public and private sector organisations for the evaluation of investments or to appraise the desirability of certain measures, decisions, or projects. It involves identifying the monetary values for all costs and benefits associated with these measures, decisions, or projects (FAO n.d.; Smart Water Fund 2011).

    With the objective of maximising the value of benefits received, CBA can help to determine whether benefits outweigh costs over a given period of timeFootnote 14 (t) and by how much (Hoffman and Plessis n.d.; Malm et al. 2015; Smart Water Fund 2011). This may be supported by a proposed timeline for the implementation of these WDM measures along with the rationale for adopting the measure (Victoria State Government 2021).

  2. (b)

    Unit Reference Value (URV). As certain costs and benefits associated with WDM measures may be difficult to quantify, an alternative method of assessing economic efficiency is the Unit Reference Value (URV). This measure was specifically developed to evaluate projects/measures in the water sector (Hoffman and Plessis n.d.; Niekerk and du Plessis 2013). The present value (PV) of the water supplied is calculated by projecting the value of water supplied over a stipulated period of time and discounting it at a predetermined rate (r). The same approach is employed to calculate the PV of costs.Footnote 15

According to this approach, costs refer to those directly related to the quantity of water delivered.Footnote 16 The URV can then be calculated by dividing the PV of all costs incurred by the PV of the quantity of water suppliedFootnote 17 (Niekerk and du Plessis 2013). The yield can be calculated on an annual basis. As part of the decision-making process, the URVs of different WDM measures may be compared and prioritised based on the lower URV values.

Phase 7: Develop demand management strategies and action plans that describe key stakeholders’ roles, responsibilities, and funding sources, consistent with statutory regulations and stakeholder vision (Kiefer and Krentz 2018; Smart Water Fund 2011; US EERE n.d.). Involving stakeholders in WDM planning serves the dual purposes of generating a feedback mechanism between water users and water service providers, while also educating water users on efficient water use (CSE 2017). Where action from external parties may be required, negotiations may be completed by this stage.

Phase 8: Implement strategies against pre-defined targets. The implementation process can include

  1. (a)

    Short-term strategies for immediate implementation and prompt visible impacts (McDonald and Mitchell 2019; Wang et al. 2020).

  2. (b)

    Long-term strategies for implementation over a longer stipulated period (China Water 2010).

Phase 9: Evaluate the effectiveness of strategies through regular monitoring and evaluation arrangements. Designate a unit dedicated to monitoring and evaluation. Annual reviews may be undertaken to assess the effectiveness of the implementation of WDM measures. This would allow certain approaches to be brought forward or deferred, based on the evaluation or new information (Pacific Water n.d.; US EERE n.d.; Victoria State Government 2021).

3.5 Key Takeaways

  1. 1.

    Developing a coherent and well-structured WDM plan, that is fit-to-context can help water service providers achieve more efficient water use by optimising existing resources before considering the creation of additional resources.

  2. 2.

    A fundamental aspect of the WDM planning and implementation processes is the inclusion of stakeholders and, in particular, stakeholder feedback. This can help improve communication and coordination between the parties involved in these processes. For water service providers in ASEAN cities, attending to stakeholder opinions (e.g. federal local authorities and residential and non-residential water users) on WDM measures can help better address both the present and future needs of water users through a multi-dimensional approach to planning.

  3. 3.

    For ASEAN cities, a holistic nine-phase approach to WDM planning is recommended. By starting with the collection and verification of data (first step) and culminating in the implementation and evaluation of the WDM measures in place, the method demonstrates how the design objectives can be met.

  4. 4.

    To further support the WDM implementation process, it is recommended that there is monitoring and assessments of the WDM measures once they are in place. Regular evaluations of the WDM ensure that they can adapt to the changing conditions and remain effective. For ASEAN cities, this may take the form of, for instance, annual or 6-month reviews by water service providers or the establishment of a WDM unit within the water ministry/water resources department of the local government to coordinate with water service providers.