More than 1,000 households have been without flushing water for nearly a month, raising fears of disease on a private estate named Healthy Gardens.
Soaring temperatures have added to concerns at the North Point complex, where residents have been waiting for a pipe to be repaired.
On June 5, staff at the firm managing a shopping mall under the six-block estate found water leaking from a section of the main seawater pipe near their office.
They asked the Water Supplies Department to cut off the supply of seawater, used for flushing toilets, until the pipe could be repaired.
But it took nearly a week for the separate firm that manages the estate to meet and discuss the situation, according to one of the residents, Sherlin Tung.
"At that point, they realised that the system of pipes needed to be replaced and that the work would be extremely expensive," Tung said. She added that every time she called management, they told her they were doing everything in their power to fix the problem.
"They told me at least three times it would most likely be fixed in a week, but it wasn't," she said.
"We were told we can flush our toilets with fresh water, but dumping buckets of water down the toilet doesn't work very well - it's only a temporary solution."
The crisis comes during one of the hottest Junes on record.
The Hong Kong Observatory has issued three very hot weather warnings this month, with the temperature hovering around 33 degrees Celsius. Chan King-ming, an environmental scientist at Chinese University, said germs could spread easily when a bucket of water is used to flush a toilet.
He added that the high temperatures would only make the problem worse, because germs would be trapped within air-conditioned apartments in which the windows were shut.
As a temporary solution, he suggested residents pour water into their toilet tanks so that they can flush as normal.
Another resident, Kitty Wong, said she and many others had complained to the management firm and district councillors, but none of them did anything about the problem.
"It's very inconvenient," she said. "It's a waste of a lot of drinking water. I'm starting to wonder if it will ever get fixed."
Leung Ka-fai, of the estate's management office, said it had taken a long time to persuade the government to help because it saw the damaged section of pipe as the company's responsibility.
He said the government eventually agreed to step in when it was overwhelmed by complaints from residents.
After that was settled, he said the shopping mall management then needed time to redirect the drinking water supply in preparation for the repair work.
Both the seawater and drinking pipes would be replaced, so it had to ensure that the estate's drinking water supply was not affected, he said.
"Now that all the preparation is done, we can start the repairs on Tuesday and everything will hopefully be back to normal by Friday," he said.
The Water Supplies Department could not be reached by the Sunday Morning Post for comment by press time yesterday.