Effective ways to reduce wastage of potable water

Records from the Meteorological Services Department have shown that there was more than average rainfall in the Klang Valley during the first three months of this year. However, there might have less rain falling over the dam catchment areas resulting in water rationing in many areas within the Klang Valley.

If this new phenomenon is here to stay, then the safe yields of all the dams would have to be de-rated and the safe operating capacities of all water treatment plants served by these dams have also to be down-rated to lower capacities in tandem with lesser rainfall over the dam catchment areas.

Without the speedy development of new water resources which is both costly and time consuming, the Government would have find effective ways to conserve and reduce wastage of treated water. If this is not done now water rationing would become a permanent feature in the Klang Valley.

Besides the usual campaign to advise the consumers to reduce water wastage in their daily consumption, there are at least three effective approaches that the Government can take to conserve water and reduce wastage.

1. Reduce water leakage in pipes

A national study on Non Revenue Water (NRW) carried out in 1988 estimated that the national average NRW was 43% of production of which 32% of production was due to leakage.

NRW is primarily leakage and the under-recording of meters, but it also includes illegal and legal metered supply. In short, it is that portion of the treated water put into the supply system that earns no revenue. An acceptable limit of NRW is below 25%.

In Selangor the overall 1987 NRW level was assessed to be 45% of production, of which 35% of production was due to system leakage. However, the 1997 NRW figure was still high approaching 40% of production.

While there was an overall reduction of NRW percentage in Selangor over the last 11 years, system leakage could be deteriorating. At an average annual growth rate of between 8 to 9%, the total length of pipes in service in 1997 could be twice that in 1988. This means that not only those pipes existing in 1988 were still leaking and perhaps even more in 1997, but also the newly laid pipes are also leaking too!

The study recommended that widespread NRW reduction and control programmes be implemented. In Selangor, some programmes were initiated in Petaling Jaya, Sabak Bernam and Kuala Selangor during the late 80s and early 90s, but the initial success could not be sustained.

The failure could very well be due to lack of a strong political will because NRW projects yield only invisible results and are not "glamorous projects".

It is about time now that the authorities not only take immediate actions to reduce losses in the distribution systems but also ensure that new pipes-laid pipes are of sound quality and are virtually leak-proof.

2. Revise water tariff

Another effective way of reducing water consumption is to revise the current structure of our water tariff. In Selangor and Kuala Lumpur, as in many other states in Malaysia, the water tariff for domestic consumption is structured in three blocks.

The first block is the lifeline quantum of 15 cubic meter per month (m3/mth) @ 42 cents per cubic meter.

The nest is for use of convenience, e.g. water closets and the like, from exceeding 15 cm/m up to 40 m3/mth @ 65 cents per cubic meter.

The last block is the penalty block for any wasteful use exceeding 40 m3/mth @ 105 cents per cu meter.

The current water tariff is far too low to discourage wastage. So to make water conservation a way of life, the tariff for the second and the third block should be raised significantly. In this respect, it was reported that in Singapore, the water tariff for households which is more than twice our average Malaysian tariff would be raised by 120% over the next three years.

3. Control of flow of water to and within premises

Lastly, the Government should consider a method of controlling the supply of potable water to premises and to limit the flow of water from all water taps within the premises.

To limit the supply of potable water from the supply main to premises, a constant flow valve, say set at a rate of 22 liters per minute, can be installed immediately after the water meter. This would regulate the rate of flow of water to the premises without appreciably reducing the pressure to the roof storage tank and the kitchen tap.

Other constant flow valves, set at a rate of 9 liters per minute, can be installed at all water taps connected to the roof storage tank. This would minimise water wastage especially in tooth brushing, bathing and the like.

The above method has been successfully adopted in Singapore.

These are long-term and effective methods of conserving water and reducing wastage. They may be politically and technologically unglamorous, but they work in the long run.

nakedeyeview.com.my 2007