The prospect of lead contamination in Hong Kong drinking water reared its ugly head again on Thursday after samples from a new public housing estate were found to contain excessive levels of the heavy metal. But water from two of the four flats involved was later certified safe by the government after separate tests showed levels to be within limits. Democratic Party lawmaker Helena Wong Pik-wan called for a truly independent water quality watchdog. On Wednesday her party revealed that tests on eight flats in Kwai Chung indicated four had excessive lead content in the water. The findings, announced by Wong and party member Andrew Wan Siu-kin, prompted the city’s Water Supplies Department to run more tests at affected flats in Kwai Tsui Estate, which was opened in April with 866 units for 2,400 people. Water Supplies Department faces bulk of criticism in tainted-water report On Thursday night a spokesman for the department said those tests, carried out on samples from two of the four flats with excessive levels in the Democrats’ exercise, had shown lead was within limits, at 2 micrograms per litre. Secretary for Development Michael Wong Wai-lun earlier on Thursday said water trucks would come to the estates to supply clean, potable water to affected residents. “As for the details – the figures, the causes – I will not speculate as we must ascertain the facts first. That is, whether the samples meet or deviate from the standards,” the minister added. The departments said building contractor Hip Hing Engineering had previously tested the water as required after the internal supply systems had been completed, and the results were within safety limits. During a radio programme on Thursday, Wong said it was strange that there were such large discrepancies in the test results, given that the party had also used a government-accredited laboratory. She suggested the government findings were wrong or could have been fudged. “It’s about the safety of the supply of materials used. Sure, you have a standard, but can you guarantee in your monitoring that they are really installing the pipes that you have authorised and not cheating?” She also said the city lacked a water safety watchdog that was truly independent. Wong said little had changed since a lead contamination scandal rocked the city in 2015 , apart from the adoption of different standards and methods for water testing, as well as stronger regulatory control of plumbing materials and plumbers. “These measures are still very far off from the comprehensive potable water legislation that the Democratic Party has proposed,” she said. Heavy metals in tap water spark fears of a second water scare The government last year proposed that a “Water Quality Regulator” be set up under the Development Bureau, which also heads the Water Supplies Department. Wong said that while frontline workers were held accountable, professionals such as building engineers, architects, contractors and even government bureaucrats were still free from liability. Can you guarantee that they are really installing the pipes that you have authorised and not cheating? Helena Wong In the latest tests, one sample from a flat in Luk Tsui House had 104 micrograms of lead per litre, more than 10 times the World Health Organisation’s standard of 10 micrograms per litre. Another sample from the same block contained 16 micrograms per litre, while two samples from Bik Tsui House contained 16 micrograms per litre and 10 micrograms per litre respectively. The Democrats conducted their tests after two residents complained about cloudy water from the taps. Water Authority representatives confirmed that the soldering material at the pipe joints was lead-free. Officials added that it was normal for there to be a relatively high amount of metal leaching from new copper alloy fittings in the initial stages. This would rapidly drop to a low level after a week to several months of usage. They suggested that new residents flush the supply system for 15 minutes twice every day for the first three days. Residents were advised to let the taps run for at least two minutes before collection if they wanted to consume tap water. The Democratic Party lawmakers urged the various government departments to disclose their earlier water test results and to inspect the pipes. In the 2015 incident, water samples from 11 public housing estates, six kindergartens, 15 schools and two public hospitals were found to contain excessive levels of lead. More than 160 people were found to have elevated lead content in their blood. The government spent millions delivering bottled water to affected residents who were afraid to use tap water. What you should know about Hong Kong’s new drinking water rules A commission led by a High Court judge concluded in May 2016 that leaded solder in the pipes had directly caused the contamination, even though, on paper, the Housing Authority, Water Supplies Department, their contractors and licensed plumbers were all supposed to use lead-free solder in fresh water pipes. In June 2016, two former directors from a subcontractor that oversaw plumbing work at three housing estates affected by the scandal were arrested for allegedly forging documents to cover up lead solder deliveries to two of the affected estates. CY Leung apologises to residents affected by lead-in-water scandal On Thursday, Wong said of the previous fiasco: “Unfortunately, the government protected its own officials and said no one was negligent and no one needed to be accountable. “They even felt that the former director of water supplies was worthy of a medal.” Former water supplies chief Enoch Lam Tin-sing, heavily criticised for his handling of the tainted water scare, was awarded the Silver Bauhinia Star – a civic honour bestowed on those who have taken a leading part in public affairs over a long period – by Chief Executive Carrie Lam Cheng Yuet-ngor this year. Ng Kim-sing, a Kwai Tsing district councillor and Democratic Party member, said he had not been shown any results on the follow-up water quality tests from replaced pipes at the affected estates in the previous scandal. “All they would tell me is simply that they are up to standard,” he said.