South African Designer Develops Wall-Based Water Harvesting

Her innovation, called Aquatecture Water Harvesting, uses modular panels fitted to building facades to collect rainwater. The panels direct the water through gutters into storage tanks, allowing buildings to capture water that would otherwise run off their walls.

The idea came to Jassat while she watched rainwater flowing down bricks across from her home.

“I was looking out the window, and there was rain falling. I just saw it on the bricks across my house. And I thought, there’s all this water gushing down,” she said.

Jassat drew inspiration from the darkling beetle, a small insect that survives in the Namib Desert. The beetle collects moisture from fog on its hardened wings and directs the droplets towards its mouth. She began exploring whether building surfaces could use a similar principle to collect water.

Traditional rainwater harvesting mainly depends on roofs and gutters. However, Aquatecture uses vertical surfaces, creating another collection option for high-rise buildings and structures with large facades. Gravity carries the collected water into storage tanks. Removable gutter sections also make cleaning easier. Jassat hopes the system will eventually supply water for non-drinking purposes, such as flushing toilets and running washing machines.

“I wanted something that was really integrated in the language of architecture,” she said.

The project grew from her research into fog harvesting and other methods of collecting moisture from the air. She worked with the engineering department at Eindhoven University of Technology in the Netherlands to explore the possibilities.

A semester-long student case study examined whether panels could collect water vapour in South Africa. The findings showed it was possible, but the amount collected was not enough to fully support the original concept. Rainwater therefore offered a more practical option.

The project later moved into pilot testing. Engineers Without Borders became involved after an engineer working on the V&A project connected the organisation with Jassat.

In 2021, Jassat selected 10 students from the University of Cape Town’s Engineers Without Borders South Africa student society to assess the system. The team included students from fields such as civil, mechanical and chemical engineering, geomatics and the humanities.

The first pilot was installed at a parking garage near Cape Town’s V&A Waterfront, opposite the Oranjezicht Farmers’ Market. Students regularly visited the site to monitor rainfall and the storage tank’s water level. The pilot reached an early milestone when its JoJo South Africa-sponsored tank filled with harvested rainwater. The team then used a hose to water plants at the nearby farmers’ market.

However, the trial also revealed challenges in predicting how much water the panels could collect. Wind and changing weather conditions made it harder to estimate the system’s performance. The researchers also examined the environmental impact of the materials used. Because local data on the carbon emissions linked to materials was limited, they worked with suppliers and transport companies to gather information. The findings were intended to help identify ways to reduce the system’s environmental footprint.

The work allowed the team to test the technology in a real urban setting and study its performance, maintenance needs and material impact. The installation at the Waterfront has remained in place, and the collected water is used to irrigate plants. Jassat said she appreciated that people could use the space without necessarily noticing the water infrastructure.

Her goal is to make water collection a natural part of building design, not a separate feature. The project has attracted attention at Dutch Design Week and other exhibitions. However, Jassat wants the interest to lead to practical use.

“I would have liked to have more impact than exposure on this project,” she said.

She added that turning public interest into investment, manufacturing and construction remains difficult.

“People love it, they want to publish it, they want to talk about it, but then when it comes to implementation, that’s where the clog really comes in,” she said.

Manufacturing is now a major challenge. Jassat wants to produce the panels as locally as possible. Interest has also come from Kenya, where an architect working on a building explored the technology. However, local producers could not manufacture the system.

She is now investigating manufacturing options in South Africa and other African countries. She is also considering manufacturers in India and China. The production process must match the technology’s environmental goals. This means choosing suitable materials, ensuring durability and making maintenance manageable.

Someleze Mbele, who worked with Jassat and other students on the project through Engineers Without Borders, said the system’s affordability and feasibility would depend on materials, manufacturing and local sourcing. The panels must also withstand weather, ultraviolet exposure, corrosion and physical damage. Gutters and storage tanks need to remain accessible for cleaning, while the connections must be safe and durable.

“Materials must resist weathering, UV, corrosion and physical damage,” Mbele said. He added that collection and storage systems should be “easy to clean and maintain and reduce blockages”.

Mbele said decentralised rainwater harvesting should support, rather than replace, large municipal water systems. Such solutions could help reduce pressure on central supplies and improve water security.

Dr Ferrial Adam, executive director of WaterCan, said buildings must also be designed to use less water. She warned that adding alternative water sources alone would not solve the problem if consumption remained high.

“We need to really look at how we save water, how we build into the future buildings that use less water,” she said.

Adam also highlighted opportunities to reuse water within buildings. For example, water from handwashing could be redirected for toilet flushing, alongside rainwater harvesting.

She said water resilience should also benefit poorer communities, where water tanks, tankers and temporary sanitation often help address gaps in public services. She added that industries, mining and agriculture must also consider how they use and pollute water.

For Aquatecture to reach more buildings, developers must be willing to invest, manufacturers must be able to produce the panels, and users must be able to maintain the systems. Funding remains a major barrier. Jassat has largely financed the development herself, apart from support for pilot projects. A Johannesburg developer showed interest but questioned whether clients would pay for the technology.

The system is not yet ready for the wider market. Although the pilots have shown that it can be built and tested, Jassat said it was too early to claim measurable benefits at a larger scale. She is still working to resolve questions around materials, manufacturing, funding and partnerships. For Jassat, the real measure of success is not media attention or exhibition displays, but whether the technology delivers usable water.

“When it is collecting water, and it is flushing those toilets, that’s when it’s successful for me,” she said.

Credit: Someleze Ndede by Bird Story Agency.