Climate Action
From Sewage to Clean Water: What Three Global Cities Teach us About Climate Ingenuity
August 1, 2025
August is National Water Quality Month, established to emphasize the importance of water for humanity, ecology, and economy. It is a great time to appreciate and take stock of our clean water resources. With climate change and human overuse triggering more frequent droughts, water is becoming an even more precious commodity, and researchers are being forced to find solutions in unusual places. So, could the answer to our water needs be running through our sewers?
The Solution in Our Sewage
Some regions are being hit harder than others. Since the year 2000, the Southwestern United States has been experiencing a megadrought: over two decades of high intensity drought. Its severity rivals the most severe droughts of the late 1500s. Exacerbated by climate change, this drought is considered the worst the region has faced in over a thousand years.
Water levels in rivers and lakes are dropping due to a combination of intensely dry weather and continued human overuse of the water that remains. Towns and cities in the region are scrambling for a solution.
Enter wastewater reclamation: the process of cleaning and reusing water which has already been used — be it from our kitchen sinks or even our toilets!
Several countries already use wastewater. Facilities like the Goreangab Water Reclamation Plant in Namibia and Changi Water Reclamation Plant in Singapore have been hugely successful in using advanced water treatment technologies to transform wastewater into high-quality, safe water.
The US could benefit from following their example. Southwestern cities across California, Arizona, and Nevada, are already viewing wastewater reclamation as a solution to their water needs. Expanding wastewater reclamation efforts to wider areas could be massively beneficial for climate resilience.
Let’s take a deeper dive into three global cities that showcase the ingenuity of wastewater reclamation.
Windhoek, Namibia, Africa
Namibia is no stranger to water scarcity. As one of the driest countries south of the Sahara, it has long sought ways to increase and make the most of its limited water supply. In 1968, it opened the Goreangab Water Reclamation Plant (GWRP) in its capital city, Windhoek.
Goreangab was the first facility in the world to engage in Direct Potable Reuse (DPR) — filtering and disinfecting sewage to extremely high standards before it is reintroduced into the drinking supply. Goreangab’s success set a precedent, and Windhoek is still a shining example to the rest of the world. In 2002, GWRP was replaced by the New Goreangab Wastewater Reclamation Plant (NGWRP), which now provides 21 million liters daily — over a third of the area’s drinking water.
The idea of drinking purified water that was once sewage is unthinkable to many, but Goreangab employs an intensive 10-step process, including several layers of filtration and disinfection, even using bacteria to help remove organic matter in the water. This ensures that the water Goreangab produces meets Namibia’s own rigorous water quality standards as well as those of the World Health Organization (WHO). And it works: the facility has never been the cause of waterborne disease.
But DPR is not the only method of water reclamation. Most places that reclaim their water for drinking follow Indirect Potable Reuse (IPR). IPR involves mixing reclaimed water with unused water in an “environmental buffer” such as a lake before treating it again to make it safe to drink. Orange County in California, for instance, has long used IPR, and many perceive it more positively than DPR despite its higher energy costs and longer turnaround times.
Singapore, Southeast Asia
One of the most famous IPR facilities in the world is Singapore’s Changi Water Reclamation Plant. With a processing capacity of 920 million liters of purified water per day, Changi is more than 40 times bigger than Goreangab.
Changi is also unique in that it sits below another facility: the Sembcorp NEWater Plant, which further purifies the water processed at Changi into “NEWater.” The final ultra-clean product is mostly used in Singapore’s many factories, but some is added to drinking water reservoirs, especially during the country’s hot summers.
The Changi plant was recognized at the Global Water Awards 2024, along with Singapore’s desalination plant, which turns seawater into drinking water. Together, these two facilities allow Singapore to maintain access to clean water despite its lack of abundant freshwater sources like rivers or lakes.
St. George, Utah, United States
Windhoek and Singapore are both large cities, but in the American West, water shortages are severe enough that even St. George, a small city of only 200,000 people, has decided to commit to the high financial costs of water reclamation. The project will cost about a billion dollars in total.
St. George has many programs in place to conserve water, including paying residents to tear up their lawns and replace them with water-efficient landscaping. Limits on outdoor irrigation further reduce water use. Residents are even subsidized to replace old toilets with more efficient models.
The new water reclamation plant, with 60 miles of new pipeline, and advanced wastewater treatment technology will enable them to stretch their resources even further.
The St. George facility is not yet completed, but by the end of 2025, it will be several times the size of Goreangab and serve surrounding towns as well. The initial plan is to use the water on fields and lawns to free up drinking water for locals. They will likely switch to DPR within 20 years.
While there are no active DPR facilities up and running in the United States right now, El Paso, Texas and San Diego, California are both considering DPR projects for the future. And diminishing regional water sources mean that we will likely see more water reclamation projects in the coming years across the Southwestern U.S.
Looking to the Future
As global temperatures continue to rise and our need for water increases, droughts are likely to worsen in frequency and severity. To ensure that everyone has water access in the decades to come, drought-prone areas must use it as efficiently as possible. That means conserving water, but it can also mean recycling our wastewater to be used more than once.
Don’t look down on wastewater reclamation, particularly DPR — thanks to the strict standards it is held to, it is entirely safe. This National Water Quality Month, think about how we can best conserve our fragile water resources. Wastewater reclamation has proven its value several times over; it could soon become a much more widespread strategy for water conservation.
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