Article

Non-revenue water loss (NRW) versus real apparent loss

To solve the mystery behind Non-Revenue Water (NRW), utilities need to play detective and think like a modern day Sherlock Holmes. Pipeline operators can look for clues using deduction, engineering forensics and the latest leak detection tools designed to help find the real and apparent sources of water loss in their water networks. Real losses refer to water lost from leaks and main failures, while apparent losses come from theft and metering inaccuracies.

Problems arise because NRW often goes unnoticed until a leak surfaces or a catastrophic failure happens. Sherlock Holmes might conclude his case with “death by a thousand small cuts,” while utilities might conclude their investigation with the loss owing to “a thousand small leaks.”

Every day, billions of gallons of water are lost worldwide due to factors including leaks, water main failures, theft and metering inaccuracies. Not only does this represent a waste of this critical resource that many people cannot reliably access, but it also represents a huge loss of revenue and energy required to pump and treat the water. To that, add a loss of confidence in the utility, especially with disgruntled ratepayers asking why their water bills are so high.

Worldwide, the NRW cost to utilities is staggering

The NRW loss boggles the mind. The World Bank estimates that NRW costs utilities worldwide about US$14 billion annually. By reducing these losses by half in areas with the highest NRW, the World Bank estimates that US$2.9 billion cash would be generated, giving an additional 90 million people access to treated water.

While the NRW rate in the United States is estimated by the United States Environmental Protection Agency (EPA) in the range of 10 to 40 percent, the water loss rate in developing countries can be as high as 60 percent – owing to fewer resources available to put against water loss management programs.

Clearly, focusing leak and theft detection system-wide is the first step in a NRW-reduction strategy to mitigate problems and improve pipeline reliability.

Globally, Pure Technologies is regarded as a highly reputable service provider with the experience, expertise and technology services designed to help manage NRW projects for both small and large utilities.

Over the course of investigating more than 3,200 kilometers (2,000 miles) of pipeline, Pure’s inline leak detection services have effectively found an average of 3.5 leaks per kilometer (2.2 leaks per mile) in large-diameter water trunk mains.

Pure helps K-Water develop its leak detection program in South Korea

Pure has developed a successful NRW leak detection program with K-water, the national bulk water utility in South Korea that supplies water across the country.

Through its water system, K-Water controls everything from collection, treatment and pumping to maintenance, inspection and rehabilitation of the nation-wide pipeline system. The pipes in these critical bulk trunk mains are primarily large-diameter, and supply water to many of the smaller cities across South Korea.

In addition to supplying treated water to these small cities, many municipalities have contracted K-water to manage and maintain their water systems as they battle the challenges of ageing infrastructure buried in often mountainous terrain.

While K-water’s critical trunk mains have a very low NRW rate, usually around 2 percent, many of its clients suffer from high rates of NRW as their aging pipeline infrastructure begins to leak.

Sahara® tethered pipeline inspection system to the rescue

To address leaks and ageing systems, K-water adopted Pure’s advanced Sahara® technology, a tethered system that combines acoustic leak detection and inline video. While many utilities around the world use this tool for large-diameter leak detection, K-water instead chose to use it as a complete condition assessment tool to provide information on its pipelines as well as the accurate location of leaks.

K-water’s expert internal engineering group utilizes the Sahara video feature to assess the condition of its steel pipes by identifying defects on the pipe wall and joints.

By using this inline detection tool, K-water has been very successful in reducing water loss, saving millions of gallons of water annually.

As the K-water example points out, carrying out regular, comprehensive leak detection programs can help utilities significantly reduce water loss. Not only do these initiatives save money and improve pipeline reliability, the programs also contribute to utility confidence in promoting long term sustainable water use.