Singapore swimming pools: 5 ‘Dirty’ facts about public pools!

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Did you know that Singapore swimming pools may not be as clean as we think?

We all love that refreshing splash in the pool, but did you know that Singapore swimming pools may not be as clean as we think?

In fact, these facts about public swimming pools in Singapore may make you…err…cringe:

1. Pollutants aplenty

Yes, there is apparently more than what meets the eye. We are talking about saliva, urine and other body waste, besides solid particles such as dirt, leaves, bandages, and sometimes, yikes, cockroaches!

2. The problem called Ammonia

Mr Sathananthan Selvadurai, lecturer at Ngee Ann Polytechnic’s School of Life Sciences and Chemical Technology tells Channel NewsAsia, “The main sources of ammonia in swimming pools are brought by swimmers: Urine, body waste and also mucus liquid.”

“These are the main contaminants, which contribute to the increase in ammonia concentration.”

He also reveals that it is impossible to expect zero ammonia in swimming pools.

There are health hazards associated with excessive ammonia. It can react with chemicals in the pool to cause respiratory problems and eye irritation.

3. What water samples from Singapore swimming pools reveal

As part of  Channel NewsAsia’s Why It Matters programme, water samples from 10 out of Singapore’s 24 public pools were collected.

These included those from Toa Payoh, Bukit Batok, Clementi, Yishun, Bedok, Jurong East, Bishan, Choa Chu Kang, Hougang and Ang Mo Kio.


These samples were tested with a reagent in Mr Sathananthan’s laboratory. The results were a revelation.

Ammonia was found in all of the samples, though in varying degrees.

4. Not cleaned fully

We think complete pool cleaning happens once a week at least, but did you know that the water in most pools is never completely replaced from the day they open?

According to Channel NewsAsia, most public pool operators replace only 10 to 12 % of their water with fresh water every few days.

That means there can never be complete eradication of ammonia.

The cleaning process involves flushing out and replenishing, and 3 stages of filtration to remove solid particles, and after that, a final stage of chlorination. To remove sediments that have settled on the pool floor like debris, hair and dirt, vacuum cleaners are used once a week.

Even after this treatment, impurities such as mucus or urine are likely to persist. Hence chlorine is constantly pumped into the pool to kill most of the germs and bacteria.

However, if chlorine level is too high, it can harm the skin. So chlorine must be added over a period of time.

5. Can be contaminated with poo, bacteria and chemicals

A study by the United States’ Centers for Disease Control and Prevention found that the average person carries 0.14 grams of faeces on his or her rear end. Children can carry up to 10 grams of faecal matter.

Harmful bacteria such as salmonella, E coli and coliform are usually present in faecal matter.

Something to think about?

And there have been cases of actual defecation in the pool. In which case, there is no choice but to close the pool, vacuum it thoroughly and do a super chlorination. A large amount of chlorine is added to the pool in order to destroy the germs.

Swimming pools in Singapore: What we can do

Of course, there are standards in place. Singapore swimming pools are required to meet the safety requirements set by the National Environmental Agency (NEA).

In line with the Environmental Public Health Act, pool water should be analysed by accredited laboratories for chemical and bacteriological quality, at least monthly. And these test results must be submitted to the NEA.

But utlimately, cleanliness in public swimming pools in Singapore is our responsibility. Here are some hygiene tips:

  • Wash your hands often. Use soap and water for at least 20 seconds, rubbing hands vigorously.
  • Shower before you swim. Always rinse yourself well before entering the water. 

Before they enter the water, wash children using soap and water, especially their bottoms. Also wash kids after they use the toilet, or after their diapers are changed. 

Harmful bacteria such as salmonella, E coli and coliform are found in faecal matter and could cause diarrhoea and dysentery if ingested.

Showering before entering the pool is also important to remove organic matter such as hair wax, cosmetic make-up and body oil.

A 2014 study by the US’ National Swimming Pool Foundation found that these organic matter react with chlorine to form by-products such as trihalomethanes and chloramines, which, if produced in large enough quantities could cause respiratory problems for swimmers.

  • Try not to swallow pool water
  • Protect others. Don’t swim if you are sick or have diarrhoea
  • Check children. Take children on frequent bathroom breaks and check their diapers often. And be sure to change diapers in the bathroom and never by the pool.

(Source: Channel NewsAsia)

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