PETALING JAYA: Selangor’s big water problems stem from the fact that it has a very low water reserve margin.
The water reserve margin is the difference between the production capacity of water treatment plants and the usage.
And every time water supply is disrupted, consumers have to wait for a long time for supply to resume.
Selangor is not alone in facing such problems. Other states with low water reserve margin include Kedah, Sabah and Perlis.
Selangor and Kedah, however, are the most critical as they are currently producing treated water at levels beyond the design capacity of their treatment plants just to meet demand.
The reserve margin in these two states is below zero, with Selangor at -1.5% and Kedah at -0.5%. Perlis has a reserve margin of 5.6% and Sabah is at 5.8%.
Association of Water and Energy Research Malaysia president S. Piarapakaran said the situation in the four states was worrying, adding that the margin should ideally be above 20%. He said plans to increase the margin were needed when the level drops below 10%.
“When the reserve margin falls to 5% and below, it enters the critical zone,” he added.
Piarapakaran said the margin can be raised by upgrading or building more treatment plants.
It can also be boosted by reducing non revenue water (NRW), which is treated water that is produced but is “lost” before reaching consumers due to pipe leaks or water theft.
Piarapakaran said Selangor’s low reserve margin, which has been dropping over the years, was one reason why it takes a long time for supply to fully recover after a treatment plant shutdown.
Water supply recovery will also take longer when high capacity treatment plants are shut down either due to pollution or urgent maintenance.
Selangor’s highest capacity water treatment facilities are the Sungai Selangor Phase 1, 2 and 3 plants which produce 70% of treated water for the Klang Valley.
Others include Langat and Semenyih treatment plants.
Recently, a 16-hour shutdown of the Bukit Badong substation for urgent maintenance work caused water supply disruption to 3.9 million residents and it took several days to resume normal supply.
In October, treatment plants near Sungai Semenyih had to be shut down twice within two weeks, because of odour pollution, affecting over 330,000 households.
This was followed by dry taps in 420,000 households in Kuala Lumpur, Petaling and Hulu Langat after the Langat and Sungai Cheras Batu 11 water treatment plants abruptly halted operations following odour pollution in Sungai Semantan, Pahang.
Disruption in raw water supply can also lead to water cuts.
In Johor, lower rainfall in August last year caused lower water levels in rivers such as Sungai Johor, leading to a month-long scheduled water distribution exercise in some areas in Johor Baru and Kota Tinggi.
Selangor state executive councillor in charge of public amenities Zaidy Abdul Talib said Selangor’s reserve margin was at about 4% and was not in the negative as alleged.
Syabas corporate communications head Amin Lin Abdullah concurred that Selangor’s water margin was currently at about 4%.
“Reserve margins often fluctuate as when there is very high demand for water at a particular time, the reserve would drop,” he said.
On whether Selangor was producing treated water beyond the capacity of its existing treatment plants, he said almost all treatment plants were currently running beyond capacity.
Amin said that was why the state was building two more water treatment plants.
“We are building Semenyih 2 and Labohan Dagang water treatment plants to raise water production to cater to the rising demand,” he said.
Amin said the state government’s target was to achieve a water reserve margin of 15% in the long-term.