The minister, together with the Director of Water Supplies Roger Wong and the chairman of the Drinking Water Safety Advisory Committee Chan Hon-fai, inspected the area on Saturday afternoon.
She said the situation of bitumen sediments in the tap water of Queen’s Hill Estate and Shan Lai Court had improved after days of cleaning.
Linn said an in-depth investigation would be carried out to trace the source of the black particles.
“To examine the interior of the water pipe, we have to make use of technology and robots. Engineers told us that using this method would not affect residents,” she said.
“After the examination and looking at the situation, we hope to submit a report to the Drinking Water Safety Advisory Committee within two weeks.”
She added the bitumen coating is prone to spalling after prolonged use of the water pipes, but authorities would start replacing the affected 400-metre-long steel pipe within this year.
Asked whether the government could speed up the process, Linn said all sorts of projects needed comprehensive planning.
The minister added that a total of 1,000 filters had been installed near the other water pipes coated with bitumen, and officials would look into whether more filters were needed for risk management.
Chan Hon-fai, the chairman of the Drinking Water Safety Advisory Committee, said the government should clean underground pipes to avoid sediments accumulating.
He added that robots should also be used to monitor the situation and ensure the pipes are cleaned thoroughly.
A resident at Queen’s Hill Estate told RTHK that she is still worried about the freshwater quality.
“Families with kids like us are even more concerned… we have reduced cooking at home, and we mainly buy bottled water,” she said.
Another resident said she does not feel at ease, even though there has been a reduction in black particles in tap water.
“It’s fine if we use it for showering, but I don’t dare drink the water. We elderly people have to pay attention to our health,” she said.