LCQ2: Prevention of water mains bursts
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Question:
The Government indicated in its reply to a question from a Member of this Council on May 14 this year that the Water Intelligent Network (WIN) implemented by the Water Supplies Department has completed the establishment of all 2 400 district metering areas (DMAs) by the end of March this year to help strengthen the management of leakage in water supply networks. However, it has been reported that incidents of underground water mains burst still occurred frequently, and multiple incidents of water mains burst even occurred in Tuen Mun District within a week in early June this year. In this connection, will the Government inform this Council:
(1) whether it has examined the reasons for the occurrence of underground water mains burst incidents one after another after the completion of the establishment of WIN, and whether it has explored improvement proposals;
(2) whether it has plans to establish more discrete DMAs within the fresh water distribution network in Hong Kong as well as install more high-technology monitoring and sensing equipment in WIN, so as to identify abnormalities in underground water mains at an early stage and strengthen the effectiveness of monitoring; and
(3) of the measures in place to minimise the impact of large-scale water mains burst incidents, including whether consideration has been given to installing backup water supply networks in districts with ageing water mains (e.g. Tuen Mun District), so as to minimise the impact of water outage on local residents and businesses in the event of the occurrence of incidents?
Reply:
President,
The reply to the questions raised by the Hon Chow is as follows:
(1) Since 2016, the Water Supplies Department (WSD) has been establishing the Water Intelligence Network (WIN) and completed the setup of 2 400 District Metering Areas (DMAs) by the end of March 2025, covering about 80 per cent of the distribution network, to enhance the management of pipe leakage. In 2024, the WSD detected over 1 200 cases of water mains leaks in government fresh water mains through WIN, facilitating the department to carry out early maintenance works. The leakage rate of water mains has decreased from about 25 per cent in 2000 to about 13.4 per cent last year.
However, the DMAs of WIN currently do not cover the fresh water trunk mains and approximately 20 per cent of the fresh water distribution network. We have to extend its coverage. Additionally, some aged water mains, such as those made of cast iron and asbestos cement, have relatively fragile exteriors. Even the water mains laid within the DMAs of WIN, they may suddenly burst upon external force impact, so we need to schedule the replacement of these water mains taking into account risk factors.
(2) Considering the above factors, the WSD began expanding the DMAs of WIN to fresh water trunk mains and the remaining 20 per cent fresh water distribution network at the end of last year. Besides, the WSD has been upgrading sensors for monitoring water flow and pressure to expedite the identification and handling of water mains with potential burst risks. The above WIN expansion and upgrading project is expected to be completed by 2027, and we have requested the WSD to explore the possibility of completing it earlier.
In addition, the WSD has been collaborating with local and Mainland academic and research institutions to study the application of other advanced technologies, such as sonar surveys and fibre-optic technology, to detect pipe leakage early. The WSD will collaborate with the Hong Kong Polytechnic University to establish a joint laboratory of "In-line Robot" in August this year to conduct high-precision inspections of water mains.
To get real-time data from different parts of the entire water supply system, we also need to work on the user end. In this regard, the WSD has mandated the installation of smart water meters in new building projects since 2018. As for existing buildings, the WSD also plans to progressively promote the installation, targeting to regulate water pressure in the water mains according to users' daily living patterns in order to implement "dynamic pressure reduction" in the entire water supply system to reduce the risk of water mains burst and leakage.
(3) The WSD implemented a territory-wide water mains replacement and rehabilitation programme between 2000 and 2015 to replace and rehabilitate about 3 000 kilometres long aged water mains.
From 2015 to March 2025, about 240 kilometres long water mains have been replaced or rehabilitated. The WSD obtained funding approval from the Legislative Council last year to replace or rehabilitate about 20 kilometres of large steel water mains. These improvement works, including about four kilometres in Tuen Mun District, are preliminarily expected to be completed by 2029 progressively.
The WSD will review the factors for water mains replacement including the risk and consequences of water mains leaks or bursts and thereby the priority of water mains replacement, and will submit short- and medium-term plans for the Development Bureau's consideration shortly.
Currently, the WSD has provided dual water mains for critical facilities (e.g. hospitals) to enhance water supply resilience. However, if a backup water mains is to be established in all areas with aged water mains, multiple factors need to be considered. These include the congested underground facilities in urban areas and whether there is available underground space, and whether the approach is cost-effective, as the construction and management of backup water mains that are mostly in standby mode will inevitably involve significant additional resources.
In the event of water main burst, the WSD will take appropriate measures to minimise the affected extent and duration of water suspension as far as possible, including temporarily redirecting water supply through connected networks.
Moreover, the WSD will continue to strengthen its response management for water supply incidents. This includes deploying sufficient water trucks to meet sudden demands in a short timeframe. The department has also updated its internal guidelines for the dissemination of information on emergency water mains repairs. The WSD has also enhanced communication with District Offices, District Council members, and the Care Teams by establishing instant messaging platforms for swift information sharing.
In recent years, the WSD has been actively promoting the digitalisation of water supply services, formulating and accelerating the implementation of smart water strategy. It is expected that management of water mains and response work will continue to improve through exploring and rolling out a series of digital projects in phases, the use of technology, timely resources allocation, organised projects management and collaboration with the community.
Thank you, President.
Ends/Wednesday, July 2, 2025
Issued at HKT 16:20
Issued at HKT 16:20
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