Water on demand – making the dream a reality

Tirana, Albanian © iStock

Intermittent Water Supply (IWS) is a challenge around the world. Raziyeh Farmani looks at the situation in different regions, based on perspectives shared by members of IWA’s IWS Specialist Group.

Access to water and sanitation is recognised as a human right by the United Nations. Limited or lack of access to safe, sufficient, physically accessible and affordable water has negative impacts on the health and prosperity of more than two billion people. In recent years, a lot of progress has been made on infrastructure delivery to improve access to drinking water. However, this has meant in some cases that access is intermittent. Providing Continuous Water Supply (CWS) to consumers is the goal of any Water Supply System (WSS). However, Intermittent Water Supply (IWS) is prevalent in most developing countries. IWS results in challenges that include inequitable supply, Non-Revenue Water (NRW), and deterioration of networks and water quality, among others.

The unprecedented scale and impact of IWS has drawn the attention of water managers and they are adapting their operations to provide water in a more equitable manner. Efficient operation and management of these systems to deliver equitable supply to all consumers remains a major challenge. Improving service delivery requires clear understanding of the problem. This can be very complex and extends beyond engineering processes, with social, economic and environmental consequences.

This article focuses on the current state of WSS in different regions affected by IWS and the causal factors contributing to the problem. Experts from IWA’s IWS Specialist Group share their regional knowledge.


Drinking water is still supplied on an intermittent basis in some Western Balkan cities. This is largely due to the lack of water resource and supply management which is worsening the IWS downward spiral, exacerbated by a lack of investment.

Transitioning from IWS to a 24/7 supply has been a distant hope for customers in Albania. But lately it seems that this hope is closer than ever to becoming a reality. There is an increased drive from government to reform the water sector, as well as investment in management and infrastructure. This, coupled with increased awareness of water conservation, could lead to a turnaround from IWS towards CWS.

Middle East and North Africa

The Middle East and North Africa Region (MENA) is the most water scarce region in the world, with water availability less than 1,000 m3/capita/year. Half of MENA’s population already live in areas under severe water stress. Moreover, with the population expected to grow from around 300 million today to around 500 million in 2025, per capita water availability is expected to halve by 2050.

Rapid urbanisation has exceeded the capacity of MENA governments to meet water demand. This has led to many challenges, such as a lack of access to safely managed water and sanitation,

IWS, competition between water users, water quality degradation, failing flood management, and environmental degradation.

More than anywhere, water in MENA is a development issue. Water management will be critical to sustainable development in the region.

Over recent decades, MENA countries have invested heavily in water infrastructure to enable more than three-quarters of the population to access basic water services, although service is often not continuous.

IWS is prevalent in most MENA countries. Water governance in the region is weak, with high levels of NRW, which may reach up to 50% of drinking water supplies. The volume of NRW is estimated at 15 BCM a year, not far short of the total installed annual desalination capacity of 17 BCM in the region.

Despite the widespread injection of subsidies to cover the difference between utility costs and revenue from customers, the relatively poor quality of public water services experienced by households drives them to supplement these with more expensive alternative water sources.

Climate change, coupled with water mismanagement and overconsumption, are contributing to IWS. It is very clear that the causes of IWS are not only due to water scarcity. The causes extend to political, social, economic, extreme events (such as droughts and pollution incidents) and technical factors, which contribute to intensify and increase the water deficit.

This situation calls for interdisciplinary approaches to resolve the problems of IWS.


In North Africa, and in Algeria in particular, average water availability was less than 500 m3/capita in 1989 against a water scarcity threshold of 1000 m3/capita. Water availability was about 411 m3/capita in 2020 and is expected to fall to 320 and 300 m3/capita in 2030 and 2050 respectively. According to the Algerian Ministry of Water Resources, at least 78% of urban residents suffered from IWS in 2013, with one in four Algerians receiving water every other day.

In this vastly adverse context, since 2010 the city of Algiers, Algeria’s capital, was able to move from IWS (which had prevailed for several decades) to CWS. The conversion followed a comprehensive diagnosis undertaken within a public private partnership (PPP), to disclose the factors hindering the continuity of supply. The causal factors included:

  • Water resources scarcity
  • High levels of NRW (almost 50%)
  • The highly uneven topography of the territory
  • Infrastructure wear and tear because of its history of IWS and inadequate maintenance procedures
  • Under-exploited production capacities, due to a lack of maintenance of installations and power supply issues
  • Poor management of the transfer network, with no supervisory control and data acquisition (SCADA) system to monitor the flows and the tank levels of 128 major tanks
  • High levels of unregistered and illegal connections

These issues were addressed by engaging important investments to drastically increase production and transport capacity, while actively managing the water losses in the distribution system and increasing customer engagement. The daily production capacity was doubled from 660,000 m3 to more than 1,300,000 m3 through the utilisation of supplementary resources (dams and desalination plants) and the rehabilitation of underground resources, in addition to the extension of treatment capacity.

At the network level, the transfer network, including reservoir and pumping stations, was doubled and monitored. This strategy enabled CWS to be achieved for a 10-year period (2010-2020). However, additional challenges arose regarding the sustainability of resource plans and network performance. These resulted in an increasingly narrower gap between resources and needs and therefore a return to IWS in 2020.

In addition, there were several practical challenges, namely:

  • Contractual constraints requiring the achievement of CWS in a short timeframe which resulted in a crisis management strategy
  • Rigorous administrative procedures for the acquisition of equipment and expertise, and short-term contracting policies, have led to the disruption of management strategies
  • The high involvement of external parties in water management, mainly due to pre-existing customer coping strategies under IWS, and no customer unions or representative structures, made communication channels between the operator and customers less effective
  • Very low, government-subsidised water tariffs fail to reflect the true cost of water production

To implement the generic process that was adopted in Algiers in other places, there is a need to adjust the process considering local conditions. There is always a need to go back to the history of the network, because any approach would depend on the quality of the city’s development at topological, topographical, structural and social levels. The challenges are comparable in the rest of the Algerian territory, which is yet to experience CWS, with even more severe conditions in terms of resources, especially when Algiers has an increasing hold on regional hydraulic space.

Southern Africa

The African Development Bank indicates that only 5% of Africa’s unevenly distributed water resources are developed. In Africa it is estimated that by 2025, 14 countries will be facing water scarcity, while 11 will be facing water stress. Furthermore, about one-third of the people in the region live in drought-prone areas. The water problems are coupled by rapid urbanisation, accompanied by poor urban planning and expanding slum populations.

Estimates by UN-Habitat show that 200 million people, equal to 60% of the region’s urban population in sub-Saharan Africa, are living in slums. Densely crowded slums create not only institutional and financial challenges but also technical challenges in accommodating the equipment required to build traditional sewer or water supply networks.

Most African countries lack adequate local funding to expand or renew their utilities and current investments in urban services are insufficient given urbanisation rates. Between 2000 and 2015, the urban population increased by more than 80% to 373 million people in Africa, and the increase in population is associated with exponential growth in living standards. When the standard of living improves, demand for water subsequently increases. It is important for water supply to increase accordingly. Unfortunately, there has not been a commensurate increase in water availability and WSS in Southern Africa.

Economic risks arising from inflation or currency depreciation can cause the costs of projects and their associated debts to rise or result in government financing being withdrawn. Infrastructure in the region is not coping with the increased water demands. When utilities struggle to collect revenue, they are unable to upgrade their water supply infrastructure, and repair and maintain existing infrastructure. IWS is not only an issue of network operations but also involves the supply-demand dynamics of the WSS.

In Southern Africa an average of 200 litres is lost as NRW per connection per day. This is double the amount lost in many developed countries. In 2020 alone, the City of Johannesburg had more than 55,000 bursts with water supply reliability at less than 20%.

Reliability is an indicator of the willingness to pay by customers, resulting in a decrease in collected revenue, compromising the ultimate performance of water utilities. Even those that are performing well with regards to operational and financial performance, show weaknesses in providing customers with high quality services, especially when compared to global benchmarks.

There are concerted efforts by many utilities in Southern Africa to increase the coverage of their water supply through network expansion. However, IWS is still a challenge. With average water supply interruptions of between six and 72 hours in certain seasons, the challenge of achieving CWS can seem insurmountable. For this to be achieved there must be a sustained focus on improving financial investments, revenue collection, and governance structures. There is a need for all stakeholders to face IWS challenges collectively. Every effort will be required to realise cumulative change.

South America

In Latin America 20% of the population has IWS between two and four days a week. The impact of IWS has serious consequences for society, including impacts on people’s health, deterioration of infrastructure, difficulties for water supply services, high costs for providers and users of the system, social inequities, wasted resources and user complaints.

There are many challenges that must be faced for the region to move from IWS to CWS, these include:

Lack of knowledge of infrastructure: cadastral surveys must be prioritised, master plans carried out, and investment plans prepared for the medium- and long-term.

Obtaining resources to execute investment: the ideal situation is one that allows economic resources to be generated through water tariffs, but these should not exceed 5% of family income. When the necessary resources cannot be obtained through tariffs, supra-municipal organisations must be involved, or PPP encouraged.

Optimise network management: in regions such as Latin America, it is common to find NRW values greater than 40 or 50%, both in medium-sized and large cities, although this problem is especially aggravated in rural populations. It is a priority to establish improvement plans that include a sectorisation strategy, pressure control, and leak detection.

Improve governance: short-term vision and political interference in WSS management is a common problem. That is why a good governance structure, with a medium- and long-term vision, must achieve continuity in personnel structure, the prioritisation of investments and the implementation of best practices in accordance with international service standards.

Social aspects: it is necessary to generate a sense of belonging to consolidate transformation. Water companies must engage with the community to generate an informed culture around water. From an internal perspective, providers must engage workers and their families to support their well-being and create a sense of inclusion.


In India IWS exists throughout the country. The WSS of India is trapped in a vicious cycle of failure, wherein failure of one factor initiates the decline in the performance of another element. Ultimately, the system fails to deliver a sufficient WSS. Shortcomings in the design, operation, maintenance, revenue generation, and institutional arrangements of the WSS are the drivers.

There are multiple drivers responsible for the prevailing IWS regime in India. One of the major drivers is the lack of appropriate hydraulic design and a highly centralised infrastructure approach. This restricts the use of total energy available in the distribution system and leads to low and unequal residual pressure. Low consumer satisfaction leads to NRW, and consumers resort to using large household or building specific storage of water. Consumers may also deploy small pumps to fetch water from distribution lines. This results in unequal pressure in the overall distribution and erratic supply patterns. Ultimately, overall wear and tear of the system increases, and operation and maintenance become very difficult. Once the distribution system is exposed to this kind of behaviour it is difficult to implement any strategies to bring the system back to the CWS regime.

Under the current WSS operating conditions, converting IWS to CWS rapidly will cause further complications, as this approach will not address the drivers leading to IWS. This method will not efficiently utilise the investment required to achieve CWS, as the WSS will revert to IWS in the case of such a direct transfer. An intermediate step of increasing the performance of current IWS should be taken to break the vicious cycle of failure. A gradual shift to CWS is achievable once the performance of IWS is improved and consumer satisfaction is reached.


The main causal factors contributing to IWS in the regions highlighted are lack of water resource and supply management, rapid urbanisation, climate change, overconsumption, lack of adequate procedures for maintenance, and intermittent power supplies.

Some of the solutions, to reduce the impacts and consequences of these causal factors or even transition towards CWS, include reforms in governance, investment in integrated management, expansion of water production and transfer infrastructure, and increased consumer engagement.

The partial or full transition of some IWS systems to CWS demonstrates that although it is not easy, it is possible. The examples above highlight the importance of integrated management, increased investment, public engagement, and continuous improvements to facilitate a gradual shift towards effective, efficient supplies.l


This article was written with contributions from Assia Mokssit, Bambos Charalambous, Eugine Makaya, Hassan Tolba Aboelnga, Jose Maria Ouro Lopez, and Pradip Kalbar.

Raziyeh Farmani is Professor of Water Engineering at the University of Exeter, UK and chair of IWA’s Intermittent Water Supply Specialist Group.