Potable water reuse: The next megatrend?

Cecilia Tortajada and Ishaan Bindal


Megatrends are reshaping the world as we know it. Urbanisation, demographic and social change, resource scarcity and pollution, climate change, mass migration, technological breakthroughs, globalisation, and shifts in global economic and political power are some of the forces that are impacting the lives of billions of people due to their ‘global reach, broad scope and fundamental and dramatic impact.’1

The interrelation of these megatrends further amplifies their  impact  on resource availability, which may become even more limited in some geographical areas. This in turn creates a threat multiplier effect, increasing political, economic and demographic tensions causing that water availability becomes a cause for global concern.

Addressing water scarcity through water reuse
Among natural resources, it is water that is irreplaceable. Water has the distinct potential to sustain political, economic, social and environmental systems. Its current scarcity and pollution are having negative consequences in terms of human, water, food, energy and environmental security.

The same megatrends mentioned earlier—economic development, population growth, urbanisation and climate change—are making it infeasible that enough water is available for the increasing number of uses and users at present and in the future.

Given the enormous socio-economic and environmental risks associated with water scarcity, either due to physical lack or pollution and increasing demand, innovations have been developed with the aim to secure water sources. These include, production of non-conventional sources of water such as water reuse for potable purposes (recycling wastewater to produce drinking water) and desalination. 2,3

Water reuse
Indirect potable reuse has existed for over a century, since wastewater started being treated and discharged into rivers, and then used by communities downstream.

Planned indirect potable reuse requires the use of an environmental buffer (lake, river, reservoir or aquifer) to store reused water before it is treated again by conventional treatment at a drinking water treatment plant and distributed to the population. In direct potable reuse, there is no use of an environmental buffer. Potable water reuse (both indirect and direct) has been recognised as a safe source of water by the World Health Organisation.4

The importance of potable water reuse lies in its benefits: it increases the amount of safe water available throughout the year and it is more resilient during droughts than traditional water resources.While these benefits have been recognised worldwide, wider application of the concept depends on the implementation of stringent policies and regulations, technical know-how, financial sustainability, engagement of the public, and societal acceptance, among other issues.

Given its importance, health and environmental risk research as well as societal concerns have become priorities for national and local governments and utilities at the project design level.6

Current examples and trends of water reuse
Potable water reuse is practiced in cities in the United States in states such as California, Colorado and Texas, to mention some of them. In Europe (United Kingdom and Belgium), Australia (Perth) and Singapore in the developed world. In the developing world, it has been practiced in Namibia (Windhoek) since 1968. It has also been implemented in South Africa (Beaufort West).7 It is also well known that water reuse has been operational in the International Space Station for over one decade. In fact, at present, there is a great deal of innovation on water reuse,8 including new methods to investigate it in space by NASA, e.g., 3D-printed components that can be assembled to reuse water in space.9

Given limited water availability and increasing demand in the above cities, and in the International Space Station, potable reuse has been the most feasible solution to have reliable sources of clean water. Associated health problems have not been reported so far in any of the cases where potable reused water is used.10

On the negative side, in the United States in the 1900s, and in Australia in the 2000s, projects were initially rejected by society due to health concerns and poor communication of the related-risks and their mitigation. Water utilities have learnt from these events and have developed better education, information and communication strategies to address the concerns of both policy makers and population.

What will determine whether or not reuse becomes a megatrend?
Due to the current situation of water scarcity and pollution, will potable water reuse be accepted and become a megatrend?

It is certainly a question of more sophisticated technological development that assures water reuse is safe irrespective of the source. However, it is also a question of updating long-term water and development policies, regulations, management practices; continuing research on risk assessment aspects, for example of emerging contaminants; financial sustainability; training within the utility sector; addressing societal concerns and so on. All these will assure populations that reused water is a reliable source of safe water, as clean as any other source of potable water.

Public engagement, education and communication are also essential, as distaste (known as the ‘yuck factor’) can make people oppose projects for no valid scientific reason.11

Water scarcity or extended droughts may eventually force the concept into becoming a reality, but this should be done within a framework of efficient water demand management where conservation is of utmost importance.

Water scarcity has become a security problem all over the world. To address it, forward-looking visions, proactive policies,12 management and financial instruments, but, most importantly, unbiased approaches that consider all possible alternatives, are necessary. Potable water reuse has the distinct potential to become a megatrend benefitting the lives of millions, perhaps billions of people, due to its ‘global reach, broad scope and fundamental and dramatic impact.’ It should thus be explored as a feasible alternative for producing drinking water locally. Broader and dispassionate views within society may allow us to contemplate novel alternatives and it may be that potable water reuse will become “the” source that will take societies forward when the rest of water sources are so stretched that they will not be enough for all.


  1. Ogletree, E.J., 1983. Review of Megatrends: Ten New Directions Transforming Our Lives, Journal of Teacher Education, September-October, Vol 34 (5), 61–62, viewed 30 March 2020, <https://web.engr.uky.edu/~jrchee0/CE%20401/Megatrends-Naisbitt/megatrends-1982_synopsis.pdf>
  2. World Health Organization, 2017. Potable reuse: guidance for producing safe drinking-water, viewed 30 March 2020, <https://www.who.int/water_sanitation_health/publications/potable-reuse-guidelines/en/>
  3. Wang, L., 2019. Better Than Running Out of Water – Desalination Plants in Australia, The University of Melbourne, viewed 30 March 2020, <https://blogs.unimelb.edu.au/sciencecommunication/2019/09/30/better-than-running-out-of-water-desalination-plants-in-australia/>
  4. World Health Organization, 2017. Potable reuse: guidance for producing safe drinking-water, viewed 30 March 2020, <https://www.who.int/water_sanitation_health/publications/potable-reuse-guidelines/en/>
  5. Orange County Water District. About Us, viewed 30 March 2020, <https://www.ocwd.com/gwrs/about-gwrs/>
  6. The City of San Diego, 2013. Water Purification Demonstration Project, Project Report, Report No. 13– 27, viewed 30 March 2020, <https://www.sandiego.gov/sites/default/files/legacy/water/purewater/pdf/projectreports/wpdpstaffreport030113.pdf>
  7. Marais, P. and von Dürckheim, F., 2011. Beaufort West Water Reclamation Plant: First direct (toilet-to-tap) water reclamation plant in South Africa. In 75th IMESA Conference, Northern Provinces, 63–64, viewed 30 March 2020, <https://www.imesa.org.za/wp-content/uploads/2015/08/Paper-6.pdf>
  8. Public Utilities Board, 2014. PUB Annual Report 2013-2014 A Fine Balance, viewed 28 March 2020, https://www.pub.gov.sg/annualreports/annualreport2014.pdf
  9. NASA TV, Investigation tests new methods of water recycling in space, viewed 30 March 2020, https://www.nasa.gov/mission_pages/station/research/news/capillary_structures
  10. US Environmental Protection Agency, 2017. Potable reuse compendium, viewed 30 March 2020, <https://www.epa.gov/sites/production/files/2018-01/documents/potablereusecompendium_3.pdf>
  11. Radcliffe, J.C., 2004. Water recycling in Australia: a review undertaken by the Australian academy of technological sciences and engineering. Australian Academy of Technological Sciences and Engineering, viewed 30 March 2020, <https://www.atse.org.au/wp-content/uploads/2019/01/water-recycling-in-australia.pdf>
  12. Orange County Water District, Water reuse, viewed 20 December, https://www.ocwd.com/what-we-do/water-reuse/

Dr. Cecilia Tortajada is senior research fellow at the Institute of Water Policy, Lee Kuan Yew School of Public Policy, National University of Singapore. She is also editor-in-chief of the International Journal of Water Resources Development. E-mail: cecilia.tortajada@nus.edu.sg

Mr. Ishaan Bindal is research assistant at the Institute of Water Policy, Lee Kuan Yew School of Public Policy, National University of Singapore.

This article was published by GLOBAL WATER FORUM, March 11, 2020.