Within any water system, there will be some leakage. One of the tasks of water demand management is to address the leaks responsibly, ensuring that this loss is kept to a minimum, and fix any excess bursts and leakages.

The International Water Association (IWA) suggests that acceptable loss should be between 8-10%, a target that South Africa misses by some margin. While suffering from high water loss due to leaks and bursts, Johannesbevurg Water has implemented several water demand strategies to aid its mandate of delivering water.

Thega Kandasamy, acting physical loss manager at Johannesburg Water, says, “With South Africa facing increasing water scarcity and ageing infrastructure, the entity has adopted a more proactive and high-tech approach to managing leaks.”

Tech forward

A key piece of technology that Johannesburg Water adopts as part of its physical loss management is pressure-reducing valves (PRVs), which lower the pressure from the incoming bulk water significantly to adequately reflect the pressure needed for residential use. This ensures that the pressure is never too great, which would result in bursts otherwise.

While PRVs provide an effective first line of defence, Johannesburg Water also deploys specialised industry technology to pinpoint leaks. Operators use an acoustic device known as a “listening stick” to detect distinctive sounds in the water network that signal a potential leak. For wider areas, a similar device called a Correaltor is used, which uses two ‘listening’ modules placed at strategic points to determine differences in noises across the water infrastructure, which could indicate a leak or burst. The Correaltor is fed information such as pipe material and diameter to accurately detect leaks across large areas.

These pieces of technology are useful in pinpointing leaks, but time-consuming. To lessen the time it takes to detect leaks, the entity has been rolling out noise loggers at various locations throughout the city, which continually “listen” to the pipes for specific noises. The data is then collected in a report, which can be used to accurately determine leak locations. These are smart devices and can determine whether noises are related to leaks or just normal system noise over time, increasing their accuracy. If a noise is logged in a pattern rather than continuously, the device understands that this irregular noise is not a leak.

Adding to the ‘smart’ capabilities of their system, Johannesburg Water also uses smart controllers which reduce pressure at specific times to reflect demand. This further allows for leak detection, as irregular water pressure at low demand times would indicate a leak.

Johannesburg Water has thus far installed 51 smart controllers and 225 noise loggers across the City, with plans to install additional smart controllers, noise loggers, and leak detection equipment.

These technologies enable Johannesburg Water to adopt a proactive rather than a reactive approach, significantly reducing response times, preventing avoidable bursts, and improving service reliability.

Kandasamy adds, “ Johannesburg Water is leveraging advanced technology and specialised equipment to find and fix leaks faster, ultimately reducing non-revenue water and improving service reliability for residents.”