Brown tap water still safe for drinking

Rusty look may be from iron silt in a building's older pipes but is not health hazard: PUB
Victoria Vaughan, Straits Times 17 Jul 09;

IT JUST looks dirty. On average, two Singapore households a day have been reporting brown or rusty tap water, but the Public Utilities Board (PUB) says it is still safe to drink.

Older buildings are more likely to be affected as they could still be using iron water pipes. PUB stopped the use of such pipes in 1980.

'Over time, iron sediment can accumulate in these pipes. Water flowing through the pipes may pick up the sediment,' said a PUB spokesman.

Such water is not a health hazard. Most complaints can be traced to pipes inside the customers' premises, PUB added.

Customers are advised to let the water run until it is clear and call PUB if the problem persists.

Mr Chia Wai Chon, the operations manager of the Singapore Plumbing Society, said: 'Buildings that are 30 or 40 years old may still have galvanised iron pipes. If the pipe is disturbed, or new sections are installed incorrectly, rust can get in the water.'

A plumber and former PUB employee, who did not wish to be named, said rare instances of discolouration could be caused by improper maintenance of water tanks that serve as an indirect water supply for public housing estates.

Both said the water was still fit to drink.

Earlier this week, reader John Kreamer wrote in to the Forum page to raise concerns about the cleanliness of his pipes. The retired United States Navy oceanographer had found copper sediment in his water filter.

'I always drink filtered or bottled water when I'm out. I don't give even my dog tap water. But I don't think the problem is unique to Singapore. In the US, I used a filter,' said the Singapore permanent resident, who was living at Spring Grove Condominium in Grange Road when the problem arose.

Mr Hari Kumar, 31, a resident at nearby Beaumont Condominium, also sees water discolouration every few months.

The professional said: 'At certain times, the water looks like milky tea. The condo management tells me it's caused by low pressure in the tank and pipes. I just run the water until it's clear.'

Although water is safe to drink here, Singapore's water provider has racked up 396 complaints from the 4.8 million people it serves. In London, water provider Thames Water has seen fewer complaints. It serves 8.4 million water-drinking customers and has had 137 complaints so far this year.

Toxicologist Peter Chan offered assurances regarding heavy metals in water.

'Copper, for instance, is actually an essential element for our existence. Still, too much can be toxic just as too much zinc or vitamin A can be. A certain trace amount can be found in water.'

PUB maintains the water pipes up to the meter for landed properties, and the master meter for residential and commercial blocks. The maintenance of the water supply system between these meters and the sub-meters is managed by town councils for HDB homes and the building management for condos and commercial buildings.

Home owners are responsible for pipes in their own premises and should get them checked yearly.
from Straits Times PDF.

Tap water's clean, but are the pipes?
Straits Times Forum 15 Jul 09;

ONLY half the story was addressed in Tuesday's report, 'Bottled water: People should be told the facts'. The other half is what comes out of your tap at home. There is no doubt that the treated water leaving PUB facilities is 'well within World Health Organisation guidelines'.

The question is what happens to the water once it leaves PUB and travels through the network of water mains and into homes?

From personal observation, which speaks louder than lab results, quite a lot. I use a water filter at home; one had a clear plastic cover so you could see what was being filtered - mud, silt, numerous unknowns and copper. The copper was from the deterioration of the water pipes in the condominium where I used to live and was easy to detect due to its colour.

An online report states that other people who are highly susceptible to copper toxicity include people with liver damage or Wilson's disease. It goes on discussing other associated health problems including vomiting, diarrhoea, nausea and stomach cramps.

What happens when the water pipes are worked on somewhere between the PUB and your tap?

Dirt and other contaminants enter your water, including micro-organisms that cannot be seen. The next time the plumber pays a visit, ask him to cut a section of your water pipe out. It could look like a clogged artery. The pipes where I was living did. So can yours.

John Kreamer

WATER PIPES: They're safe, replies PUB
Straits Times Forum 18 Jul 09;

NATIONAL water agency PUB thanks Mr John Kreamer for his letter, 'Tap water's clean, but are the pipes?' on Wednesday.

The PUB has a stringent water quality monitoring programme in place to assess and ensure that our water meets the World Health Organisation's (WHO) guidelines. Over 80,000 tests are conducted monthly, based on more than 290 parameters, surpassing about 130 specified by the United States Environmental Protection Agency and the WHO.

They include the testing of representative water samples taken daily from the distribution network and customers' taps at different locations throughout Singapore.

Apart from independent checks by the Director General (Public Health), National Environment Agency, PUB's management of water quality is reviewed twice a year by an independent external audit panel comprising foreign and local experts.

Corrosion-resistant materials such as lined ductile iron and steel pipes with a lifespan of 50 to 70 years are used for PUB's water supply network. PUB requires building owners conducting works on pipes to engage licensed water service plumbers who must ensure that the water supply system is sterilised before being put back into service.

Management corporations and town councils must engage a licensed water service plumber at least once a year to inspect and, where necessary, clean and disinfect their water tanks and certify that the tanks are fit for drinking water storage. The plumber must submit his certification and water sample test reports to PUB. In addition, the PUB conducts spot checks and water sample testing to ensure that the tanks are properly maintained.

The discolouration of water filters is caused by the accumulation of minerals, including iron, over time. Although the iron content in PUB water is almost negligible, the discolouration will eventually be noticeable when large quantities of water pass through the filter. PUB water naturally contains a small amount of minerals and their concentrations are monitored and kept well within WHO guidelines.

Over time, sediment can also accumulate, especially on older premises which use iron pipes and fittings. If this is disturbed, it can be picked up as water flows through. Discoloured water caused by sedimentation is not a health hazard.

Customers are advised to let the tap run until the water is clear should they encounter discoloured water from their taps. However, if the discolouration persists, customers can call PUB on 1800-2846600 for assistance.

Chong Hou Chun
Director, Water Supply Network

Doctor: Contamination unlikely, no reason to worry medically
Straits Times Forum 18 Jul 09;

MR JOHN Kreamer raised a very intriguing subject in his letter on Wednesday ('Tap water's clean, but are the pipes?') when he posited that tap water may possibly not be salutary to health, as the treated PUB water may become contaminated during its journey through water pipes to our homes.

Indeed, I would imagine that microbiological, chemical and physical contamination will occur should the integrity of the pipes be breached either through the use of outmoded pipe material - like lead, which has since been replaced with other materials like steel, copper or plastic - or actual physical interruptions caused by man or nature.

Short-term complications due to this must be rare since doctors here hardly ever diagnose gastroenterological disturbances due to consumption of tap water alone.

Since the proof of the pudding is in the eating, I anecdotally presume that the water straight from our faucets is almost entirely free of contaminants with the exception of the odd case here and there.

As for long-term complications arising from drinking tap water, especially since Newater has been recently added to our diet, I suggest that the medical fraternity be on the lookout for this; although, with the increasing lifespan of the local populace, doctors will be hard put to attribute any long-term morbidity solely to the act of drinking potable water from taps.

Very often, vendors of water filters demonstrate sludge and impurities from our taps by showing the inordinate amount of debris trapped in them when the filters are used over some duration.

Unlike static filters, our alimentary canals remove detritus regularly from our bodies. Even in octogenarians who have consumed nothing but tap water since the day they arrived in this world, examination of their bowels during surgery and post-mortems never show the accumulation of slurry sediment which one finds in old pipes. I conclude that Mr Kreamer worries unnecessarily.

Dr Yik Keng Yeong

Query over coating of Newater pipes
Straits Times Forum 22 Jul 09;

I REFER to Saturday's Forum letter by Dr Yik Keng Yeong, "Doctor: Contamination unlikely, no reason to worry medically", in which Dr Yik mentioned about Newater having been recently added to our diet.

The specification for the coating of Newater pipes allowed for polyurethane to be used for the lining of the pipes and fittings. Stringent tests were also supposed to have been carried out to ensure that it is suitable for potable water. Yet for whatever reasons, primer has been approved for use in Newater pipes.

Primer is manufactured with xylene and chlorinated rubber and xylene is a hazardous material. There is approved polyurethane material for potable water like those used for London, but primer is not allowed. I would like to know how PUB can allow it.

Goh Guek Cheng (Ms)

Newater pipes lined to ensure long-term integrity
Straits Times Forum 27 Jul 09;

PUB, the national water agency, refers to the Forum Online letter by Ms Goh Guek Cheng last Wednesday, 'Query over coating of Newater pipes'.

The pipes used to convey Newater adhere strictly to standards for potable water. These include Singapore Standard SS375 and United States National Science Foundation Standard NSF61. The pipes are lined to ensure long-term integrity and durability. For the lining to adhere strongly to the pipes, primer is used to prepare the pipe surfaces to receive the lining.

But the xylene present in the primer, if any, is a volatile compound and will evaporate as it dries and cures. The primer will not come into contact with Newater as there is an additional polyurethane lining on top of the primer within the Newater pipe.

Our routine tests carried out on both Newater and reservoir water do not show traces of xylene.

PUB thanks Ms Goh for her feedback.

Chong Hou Chun
Water Supply Network