Lab tests confirmed that the black particles found in the drinking water supply of some households in Taikoo Shing over the weekend were bitumen sediments while the water samples collected from the residential estate met Hong Kong’s drinking water standards, the Water Supplies Department said Sunday.

The department said in a statement that water pressure changes caused by the temporary redirection of water supply near the housing estate in Quarry Bay on Saturday night stirred up bitumen sediments inside the pipes.

“These sediments are inert substances and pose no harm to human health,” the WSD said.

The department immediately sent staff members to Taikoo Shing after the the estate management office notified the WSD about residents finding black particles in their drinkign water supply.  

The initial investigation also revealed damage to one of the filter facilities at Taikoo Shing's public water inlet, which may have allowed a small amount of sediment to enter the estate's public water pipes, causing particles to appear in some households' drinking water.

The WSD said it routinely inspects these inlet filters and the most recent check on Nov 3 showed no abnormalities. The damaged filter was repaired Saturday night, and the department said it has strengthened pipe flushing in the affected system.

Water trucks have also been stationed on-site to provide temporary water supply to residents while the WSD has set up a service counter at the site, working with the property management office to assist in flushing water meters and to answer enquiries.