The Water Supplies Department on Sunday said it has fixed a damaged filter that likely led to black particles entering the fresh water supply system at a major residential estate in Quarry Bay. Authorities added that the impurities are likely bits of bitumen.

Some residents of Taikoo Shing had reported finding black specks in their tap water, prompting officials to collect samples for testing.

"According to past experiences, we believe the black particles in the water were bitumen used for coating pipes," the department said in a statement.

The department explained that it redirected water supply near Taikoo Shing on Saturday evening as part of maintenance work, and the change in water pressure might have stirred up sediments in the pipes.

A damaged filter screen at the inlet of the estate's public water main was suspected to have allowed a small amount of particles to enter the fresh water system there, authorities added.

The department said it found no irregularities during the last routine inspection on November 3.

"The filter in question was repaired [on Saturday night], and the Water Supplies Department has bolstered efforts in flushing the relevant pipes," it said.

"To reassure residents, the department has deployed water wagons to provide temporary water supply."