Reducing water loss: Drop by drop, pipe by pipe

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Authorities have been quietly working to reduce unaccounted-for water (UFW) in Bengaluru and have achieved considerable success.

From a high of 49 per cent in 2012-13, the UFW in the city is now down to 34 per cent. While more than one-third of the water supplied to the city is still going down the drain, the situation is not as bad as it was about 10 years ago.

This has been made possible by big reductions in the central, southern and western divisions of the Bangalore Water Supply and Sewerage Board (BWSSB). In each division, the UFW has decreased by more than 50 per cent.

The success came at a considerable cost — Rs 603.7 crore to be precise. The BWSSB had to replace old, broken pipes by investing in new technology and roping in external agencies.

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Reducing the UFW is key to meeting the water requirements of a rapidly growing Bengaluru. The UFW is the difference between the quantity of water supplied to a city and what actually reaches individual consumers. The UFW is caused by water leaking due to broken pipes, illegal connections and faulty meters. A low percentage of unaccounted-for water will help the ongoing efforts to bring more water to the city through the Mekedatu balancing reservoir project.

BWSSB Chief Engineer (West) Devaraju M explained the UFW project:

The first step is to monitor the water flow and identify the water leakage points, both visible and invisible. Identifying faulty meters and double connections is equally important.

The BWSSB took up the UFW project in 2004 on a pilot basis. But it took another nine years to launch it on a full scale. Phase 1, funded by the Japan International Cooperation Agency (JICA), took off only in 2013.

Phase 1 covered the South, West and Central divisions, which together cover 132.5 square kilometres of the 800-odd square kilometres served by the BWSSB in Bengaluru.

In the South division, spread over 52 square kilometres, the UFW came down from 49.96 per cent to 24.41 per cent. In the Central division, where the unaccounted-for water was a staggering 52.78 per cent, it’s now 21.35 per cent. In the West, it’s down from 45.27 per cent to 20.33 per cent. (See the table)

With the completion of Phase 1, the BWSSB is saving at least 5,000 million litres of water every month.

The success of Phase 1 has prompted the BWSSB to expand the UFW project to more parts of the city. The water board has launched it in another 22 square kilometres spanning three assembly constituencies (Byatarayanapura, CV Raman Nagar and Shivajinagar) which together have a 400-km-long water pipeline network.

Phase 2, which costs Rs 203 crore, has a November 2022 deadline. The goal is to reduce the UFW in the three assembly constituencies from the current 47 per cent to under 10 per cent.

According to a senior BWSSB official, the UFW project needs to be taken up only on 225 sq km of the 800 sq km under the water board.

These 225 square kilometres cover old Bengaluru areas which have cast-iron pipes with lead joints laid 70-80 years ago.

“These pipelines are being replaced on priority. Of the 225 sq km, we have already covered 132.5 sq km while the work is going on in another 22 sq km,” the official added.

Pipelines in the remaining 575 sq km need not be replaced because they were laid only 10-15 years ago and are still good enough, the official said.

Out of the 400-km pipeline network in the three assembly constituencies, work has already been completed on 225 km, another BWSSB engineer said.

Unlike Phase 1 where only vulnerable or damaged pipelines were replaced, the BWSSB is replacing all the pipelines in Phase 2, the engineer said.

“It’s a capital-intensive project. We had spent Rs 274 crore in the West division where 54 sq km was covered. But in Phase 2, we have to spend at least Rs 203 crore on just 22 sq km. While replacing pipelines is expensive, we have to pay nearly three times the pipeline cost for road restoration,” the senior official quoted above said.

Besides, the survey, design and establishment of District Metered Areas (DMA) have also been completed. Twenty-six DMAs will be established as part of the project.

According to the project’s technical supervisors, one DMA is installed for every 2,500 connections. “It helps estimate how much water is entering an area, how much of it is flowing out and the quantity recorded by water meters,” a technical officer said. “This helps us identify the precise leakage points or unauthorised connections.”

Apart from identifying and replacing faulty pipelines, the BWSSB is also cracking down on unauthorised connections.

The board has been able to identify and regularise more than 30,000 illegal connections. During a recent drive, BWSSB officials were able to identify bypass connections and remove 4,500 of them. “We are sure this will help bring down the unaccounted-for water,” the official said.

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