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LCQ19: Problem of sewage backflow at public rental housing units
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     Following is a question by the Hon Doreen Kong and a written reply by the Secretary for Housing, Ms Winnie Ho, in the Legislative Council today (November 16):
 
Question:
 
     Recently, a public rental housing (PRH) tenant complained to me that a serious problem of sewage backflow had occurred in the unit she lived, and this was not the first time the situation occurred. The furniture in that unit was soaked in the backflow sewage, and elderly family members fell and injured due to slippery floor. It is learnt that the situation of sewage backflow has frequently occurred in PRH estates. In this connection, will the Government inform this Council:
 
(1) of the number of PRH units in respect of which complaints were received by the Hong Kong Housing Authority (HA) about sewage backflow in each of the past three years;
 
(2) as it is learnt that the problem of sewage backflow still occurs in PRH units completed after 2018, whether the Government has studied the causes of such problem; if so, of the details; if not, whether it will conduct a study immediately, and what improvement measures the HA has put in place to cope with such problem; and
 
(3) whether PRH tenants who have incurred losses and sustained injuries arising from sewage backflow in their units can receive compensation under the relevant regulations and the public liability insurance taken out by the authorities?
 
Reply:
 
President,
 
     Our consolidated reply to the question raised by Hon Doreen Kong is as follows:
 
     The Hong Kong Housing Authority (HA) has all along been striving to provide quality, comfortable and hygienic homes to our tenants. For the design of drainage system in new public rental housing (PRH) estates, HA has minimised the number of bends along the pipework and installed additional vent pipes to balance the air pressure in the drainage pipes with a view to reducing potential sewage backflow. HA has also updated its Technical Guide to improve the design of drainage system in new PRH estates in order to improve environmental hygiene such as increasing the diameter of the cross vent pipes connecting waste pipes and anti-syphonage pipes; increasing the height of the open end of vent pipes above the roof level away from any window, opening or fresh air intake of a building and from the common boundary with any adjacent site. During intake of newly completed PRH estates, HA's estate management staff will remind tenants not to dispose of any decoration waste into the sanitary fitments. Staff of estate management office will also increase the frequency of inspection to drainage pipes and manholes in the decoration period in order to maintain free flow of the pipes.
 
     As for existing PRH estates, HA provides regular inspection and maintenance services continuously, including conducting inspections to tenants' drainage facilities of PRH buildings aged 10 years or above through the Total Maintenance Scheme; replacement of pipework of lower floor units with ones which are of larger diameter; installation of non-return valves and/or addition of separate drainage pipes when necessary and situation warrants for those PRH units suffered from backflow to avoid recurrence. For the drainage system in common areas of the estates, HA arranges regular appraisal on the conditions of cast iron pipes, extends the vent pipes on roofs, inspects underground drain pipes by means of closed-circuit television, inspects and clears manholes, uses high pressure water jetting to clear the clogged underground drainage, etc.
 
     Apart from enhancing the design of the drainage system, proper use of the sanitary fitments by tenants is also of vital importance. One of the major causes of sewage backflow is the blockage of drainage facilities by sundries. The most common items HA found when clearing blocked pipes are hardened cement, stones chips, newspapers, towels, non-woven fabrics, bottle caps, beverage cans, plastic bags, plastic table wares, toothbrushes, etc. Therefore, we appeal to tenants from time to time not to dispose of any decoration wastes, daily necessities, etc in the toilet pans to avoid causing blockage of the pipework at the lower floor units of the same block. Tenants should also pay attention to the flow of water of the toilet pans in their units. If the flow is not smooth, which is a symptom of blockage, tenants should immediately notify the estate office for inspection in order to prevent sewage backflow. HA has reminded the tenants on the proper use of the sanitary fitments by means of the Estate Newsletters, leaflets on the maintenance and repair of sanitary fitments, videos broadcasted in the Housing Channel as well as via In-flat Inspection Ambassadors deployed under the Total Maintenance Scheme.
 
     In 2020 and 2021, HA received a total of about 500 sewage backflow cases. In 2022, HA has so far received about 135 cases.
 
     HA has taken out public liability insurance to indemnify HA and its staff for their legal liability to pay for third party's property damage and/or injury arising out of their operation. If HA or its staff is found legally liable after the investigation by the independent loss adjuster, HA will compensate the claimant for his/her loss according to the terms and conditions of the insurance policy.
 
Ends/Wednesday, November 16, 2022
Issued at HKT 12:08
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