LCQ18: Quality of drinking water in public rental housing estates

Following is a question by the Hon Paul Tse and a written reply by the Secretary for Development, Mr Michael Wong, in the Legislative Council today (June 13):
After a number of drinking water samples taken from a number of public rental housing estates were tested and found in July 2015 to have a lead content exceeding the provisional guideline value set by the World Health Organization (lead in drinking water incident), the fresh water mains in a number of housing estates (including Lower Ngau Tau Kok Estate) have been comprehensively replaced.  However, a number of residents of Lower Ngau Tau Kok Estate have recently complained to me, claiming that the quality of the drinking water supplied to their units was poor.  Based on my on-site observation, the drinking water is turbid and foamy and even looks like cappuccino when put in a coffee cup.  It is learnt that the residents of that estate have repeatedly enquired with the contractor engaged for the replacement of the fresh water mains and the Housing Department about the reasons for the drinking water being turbid and foamy, but the personnel concerned merely replied that the drinking water of that estate was of normal quality and advised the residents to run the tap for about half an hour every day before using the water for drinking.  On the other hand, rainfall to date this year has been lower than that in previous years, resulting in low water storage and dry bottoms of some reservoirs.  The Water Supplies Department also calls on members of the public from time to time to conserve water.  In this connection, will the Government inform this Council:
(1) whether it has studied the causes for the drinking water in Lower Ngau Tau Kok Estate being turbid notwithstanding the fresh water mains therein have been comprehensively replaced;
(2) whether the authorities, following the replacement of fresh water mains for a number of estates in light of the lead in drinking water incident, have conducted regular sample tests on the quality of drinking water therein; if so, of the details, and set out the sampling dates and test results by name of estate; if not, the reasons for that; whether the authorities received complaints in the past three months about turbidity of drinking water in other estates;
(3) whether it has assessed, in the event that all of the households of Lower Ngau Tau Kok Estate follow the advice to run the tap for half an hour every day before using the water for drinking, (i) the increase in the daily water consumption of that estate, (ii) the increase in the monthly water charge payable by each household on average, and (iii) whether the drying up of reservoirs will be exacerbated; whether it has assessed, when households of other estates who face the same situation of drinking water being turbid and foamy run the tap for half an hour every day before using the water for drinking, if the water consumption will increase substantially and result in the Government having to spend more public money on purchasing Dongjiang water in the next agreement on the supply of Dongjiang water to Hong Kong; and
(4) as the advice of running the tap for half an hour before using water is contrary to the Government's advice to conserve water, and members of the public are caught in a dilemma, how the authorities solve the hygiene problem of drinking water?

Since March 2016, the contractors of the Hong Kong Housing Authority (HA) have been carrying out replumbing works to replace sub-standard water pipes for the 11 affected public rental housing estates, including Lower Ngau Tau Kok (LNTK) Estate Phase 1.  The replumbing works comprise two parts, namely those in the communal areas and those inside individual flats.  All the works in the communal areas were completed in the second quarter of 2017.  At present, the contractors are replacing water pipes inside individual flats and have completed about 80 per cent of the works.
Upon the completion of the works by stages, the contractor concerned has to comply with the requirements of the Water Supplies Department (WSD) to take water samples for water quality tests.  Only when the test results meet the standards would the WSD confirm the works is in compliance with the relevant requirements.  To date, the test results of all water samples taken from the communal areas and individual flats which have completed replumbing have met the required standards.
The consolidated response to the four parts of the Hon Paul Tse's question is as follows:
To follow up on the question about the quality of water supply to LNTK Estate, the WSD launched an immediate investigation.  On June 2, the WSD staff collected water samples from two government fire hydrants close to the water supply point to LNTK Estate and from a toilet in the LNTK Estate Plaza. According to the test results, the water samples met the required standards, indicating that the water supply to LNTK Estate was normal.
The WSD and the Housing Department (HD) also checked records of the past three months and found no water quality complaints from LNTK, including those about odour and colour.  The HD received a report on unpleasant odour and turbidity in fresh water from the resident of a flat in Kai Ching Estate that has completed replumbing.  The contractor of the HA conducted an inspection and found no such water quality problems. Other than this case, neither the WSD nor HD has received report on water quality problems from other public rental housing estates that have completed repumbling similar to the one in LNTK Estate described in the question.
Furthermore, the WSD monitors the quality of drinking water at consumers' taps through the Enhanced Water Quality Monitoring Programme that the participating premises are randomly selected from all water accounts, including those that have completed replumbing.  Test results of water samples collected from the premises will be compiled as water quality statistics for publication on the WSD's website which is updated once every week.
Furthermore, the WSD promulgated the WSD Circular Letter No. 6/2017 in mid-2017 requiring all completed inside services of all new buildings to adopt a systematic flushing protocol in order to reduce metal leaching from the newly installed pipes and fittings to a low level.  As for the existing buildings, the WSD published the "Water Use Tips" to suggest residents run the drinking water taps every morning and night for about 15 minutes, and run the tap for two minutes each time before using the water for drinking or cooking purposes in the first three days following the completion of replumbing works.  Since residents can save the flushed water for non-potable uses, such as watering plants, cleaning floors and washing, there will not be water wastage.
Ends/Wednesday, June 13, 2018
Issued at HKT 17:01