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Featured Stories

26 June 2018
Causes of water discolouration

Singapore enjoys good quality tap water due to a robust water treatment process and a rigorous water quality monitoring programme that covers the entire water supply system. Our tap water is well within the World Health Organisation (WHO) drinking water guidelines and is safe to drink without boiling or further filtration. However, do you occasionally notice that your water appears discoloured or contain particles, and wondered why this happens? We reached out to Water Supply Network (WSN) Senior Engineer, Kok Yi, to answer some of the common burning questions about causes of water discolouration, as well as listen to some of his experiences dealing with such situations.

water discolouration

In an interview with Kok Yi, he shared that cause of discoloured water is due to the re-suspension of mineral sediments. These minute amount of minerals are inherent in our water and will settle at the base of the water tanks, water mains and also at the end point of the distributing pipes over time.

The common causes of discoloured water to the re-suspension of mineral sediments can be due to maintenance operations such as the routine cleaning of water tanks, flushing of service pipes in buildings by Town Councils, Management Corporation Strata Titles (MCSTs), building owners and the operation of fire hydrants. However, discoloured water can also occur as a result of corroded internal fittings within house premises or stagnant water in service pipes and water service installations as a result of infrequent use.

In addition, heavy drawoff from a water mains leak may also lead to the temporary re-suspension of the mineral sediments which appears as discoloured water at the customer's tap.  To clear brownish water from PUB's water mains, our officers will flush the water containing re-suspended mineral sediments out from the water mains in a controlled manner until the water clears up.

Kok Yi shared that some of the common reports that his team receives on discoloured water is when customers notice brown stains on the cloth filters that they attach on their taps. He commented that they may see brownish deposits on their filters over time due to the minute amounts of minerals inherent in the water supply. "Discolouration of the filter will be noticeable when minerals absorbed in the filters are oxidised. PUB discourages the use of any filtration system as bacteria could grow on the filters if they are not maintained or replaced regularly." says Kok Yi.

Kok Yi also noted that PUB takes every single case of water discolouration into serious consideration. Feedback on discoloured water will be investigated to establish the cause and ensure that the PUB water supply is clean and clear. Often, Kok Yi and his team works closely with customers, Town Councils and building maintenance to ensure the water is fit for potable use.

Depending on findings, the engineers will conduct emergency pipeline operations isolate the source and prevent further discolouration if the source is from PUB water main. To clear brownish water from PUB's water mains, officers will flush the water containing re-suspended mineral sediments out from the water mains in a controlled manner until the water clears up. If the discolouration is from the PUB water mains, temporary water supply, such as water bags and/or water wagons, will be provided for the customers affected. However, if the source of discoloured water is within the customer premises, the officers in charge will advise the customer to rectify the problem by replacing or repairing the appliances or pipes.

If you do encounter discoloured water, Kok Yi advised customers to first run their taps and flush any water tanks inside their premises until the water runs clear. If the water has not cleared up after 10 to 15 minutes, customers can call PUB's hotline at 1800-CALL-PUB for assistance. Meanwhile, customers should also try to determine the source of the discoloured water. If the discoloured water is localised to be from a single appliance, this could indicate a faulty appliance. PUB officers also work very closely with Town Councils and SCDF to ensure maintenance operations are conducted with care to minimise discoloured water incidents.

​On how customers can do their part to minimise water discolouration incidents, Kok Yi advised customers to always check that their appliances are in good working condition and replace them when there are signs of corrosion. Customers can also do their part to ensure corrosion resistance materials are used for their service pipes. He also noted that customers should flush the water before use, especially if water in their service pipes or water heater has been stagnant for a long period of time. 

1 June 2018

Our Water Heroes #5 – Tay Manjun
Our Water Heroes

"Ever-Ready" – Water Quality Department (WQD) Manjun Tay describes her team as having to be alert 24/7 to carry out prompt investigations on water quality issues when needed. As a chemist, Manjun is responsible for water quality testing, where she analyses water samples collected from source to tap – including reservoir, sea, river, treated water, NEWater and desalinated water. Besides water quality testing, Manjun's team perform calibration and quality checks on analytical instruments to ensure data accuracy and reliability. By measuring test parameters such as pH, conductivity and turbidity, she monitors the trend of water quality of each water matrix and highlights anomalies to PUB's operations departments. This comprehensive water quality management programme helps to ensure that Singapore's tap water is well within World health Organisation (WHO) standards.

Our Water Heroes

Never one to settle, Manjun and her team worked together with an external vendor to develop a new integration system that improves work productivity and effectiveness of water testing. The Automated Laboratory System (ALS) was introduced at the end of 2017 to reduce manpower, human error and manual testing time while ensuring data accuracy and reproducibility, hence protecting the integrity of the water samples.

Our Water Heroes

When asked what is her greatest satisfaction at work, Manjun feels blessed that she is playing a big role in safeguarding Singapore's water supply, and highlighted that her recent overseas trips to less developed countries where water is very scarce and not safe for drinking makes her appreciate her work more. 

Our Water Heroes

"I feel proud when I see the public and visitors feel safe drinking our water straight from our taps."

30 May 2018

Our Water Heroes #4 – Zhafri Shah
Our Water Heroes

"Meaningful" – was how Water Supply Network (WSN) officer Zhafri Shah described a day's work in PUB. Studying environmental engineering in National University of Singapore sparked his interest in the water industry, and he was keen to play a part in ensuring continuous good quality water supply for Singapore .

Our Water Heroes

"There is never a day that is the same", says Zhafri Shah of the past eight months that he has been in his role. His job includes planning, developing, reviewing and managing the regulatory framework, legislative instruments and enforcement regimes for clean water supply in Singapore, as well as meeting consultants, engineers, architects and licensed plumbers (LPs) to clarify PUB's requirements on the maintenance and security of water storage tanks. This is important as the water storage tank serves an important purpose to our HDB flats, supplying even-pressured water to units on level 5 and above, hence ensuring clean water is readily available to residents.

Our Water Heroes

To ensure that water storage tanks are fit and safe for the storage of potable water, Zhafri Shah and his team also conduct routine site audits, where they evaluate cases of non-compliance and put into place enforcement action to prevent repeat offenders. With over 18,000 buildings with 70,000 water storage tanks in Singapore's high rise buildings, Zhafri Shah takes his work very seriously as they are the last mile of the water distribution system before it reaches the customers. As a customer himself, Zhafri Shah is able to relate to the importance of water security.  "My job is impactful because it helps ensures good quality water to the public. I hope to continue instilling in the young that water is a precious resource that we should treasure."

28 May 2018

Our Water Heroes #3 – Wong Lei Lei
Water Heroes

"Exciting" – Water Supply Network (WSN) officer Wong Lei Lei shared that she finds her work exciting because she encounters different challenges every day, which requires her to use varied skillsets to tackle these problems. 

Our Water Heroes

The distribution network is a key node in the water supply system, and ensuring that the network runs smoothly like clockwork to deliver a clean and continuous supply of water to the customers 24/7 is paramount for Lei Lei.  

Our Water Heroes

At the frontline of ensuring minimal water disruption to Singaporeans, a day's work includes prioritizing feedback on water quality, pressure, pipe leaks, and attending to those which require attention urgently. Her team also relies on smart sensors installed within the water supply network that monitor parameters such as water pressure, flow and quality to better understand the network's health. 

Lei Lei also studies ways to enhance the water supply network on a regular basis so that the network is more robust and maintenance can be carried out on the network with minimal disruption to the customers. 

Our Water Heroes

Lei Lei shares that her most memorable workdays are when "work stretches past wee hours", as a lot of work involving pipeline isolation is done at night to minimize disruptions, and the team works hard together to resolve water supply issues. Besides the day to day operational work, Lei Lei derives immense satisfaction when she is able to resolve issues for customers so that Singaporeans continue to enjoy a safe and continuous water supply straight from  their taps. 

26 May 2018

Our Water Heroes #2 – Cheong Xin Ling
Our Water Heroes

“Challenging” –  As the Plant Manager, Water Supply Plant (WSP) officer Cheong Xin Ling oversees operations and maintenance of Bedok and Pulau Tekong Waterworks.  At the waterworks, the raw reservoir water is treated, filtered and disinfected to free the water of harmful bacteria, making it clear, sparkling and safe for consumption. Managing the waterworks is challenging yet interesting, and every single day is a learning process for her. Besides analysing water quality data and trends to ensure safe drinking water, Xin Ling also works closely with the maintenance team to ensure the process equipment are in good working condition. She also frequently conducts safety checks and supervises workers to ensure a safe working environment.

Our Water Heroes 

Xin Ling shared that her interest in the water industry was sparked in 2002 when NEWater was introduced as a safe and sustainable source of water for Singapore. As a chemical engineering graduate, she was interested to learn more about the NEWater treatment process and the chemistry behind it. 

Our Water Heroes

When asked what drives her to do better at work, Xin Ling reveals that she feels proud to be part of the team that works behind the scene to supply potable drinking water. Ensuring that Singaporeans can “drink water straight from the tap” is something which gives her team great satisfaction and pushes them to constantly strive to improve work processes.

24 May 2018
Our Water Heroes #1 – Mohd Rizdwan Yunos 

Our Water Heroes

“Interesting” – Catchment and Waterways (CW) officer Mohd Rizdwan Yunos proudly describes his job as “doing things that people don’t usually get to try”. This would include taking a boat out around the Serangoon reservoir every morning to do surveillance patrol and check for the raw water quality. Weekly samples are taken and data readings collected from the multimeter are sent to PUB’s Water Quality Office (WQO) for further analysis. Besides this, Ridzwan also frequently patrols the reservoir for illegal fishing activities or acts of vandalism.

Water Heroes

Anticipating unexpected queries from the public, especially at night, about oil spills or fishkills are all part of what he faces almost on a daily basis. However, Rizdwan enjoys attending to the public queries and feels a great sense of achievement when he is able to provide satisfactory replies to their questions. The dynamic work environment ensures that Rizdwan and his team are always alert and kept updated on latest findings so that they are able to give informed responses to the public queries. 

Water Heroes

Rizdwan shares that he takes great pride in his work because he plays a part in maintaining the water quality in the reservoir, hence ensuring a safe and continuous water supply for Singaporeans. “Being able to educate the public about the reservoir and what we do to maintain the cleanliness of the reservoir gives me great satisfaction and drives me to constantly do better.”

March 2017 - April 2018

Download past featured stories on Singapore World Water Day 2018 [PDF]. 

Download other past featured stories from March 2017 to Janaury 2018 [PDF].