Hong Kong’s ticking time bomb: Rapidly ageing water pipes

6th December 2023 – (Hong Kong) Hong Kong prides itself as one of the world’s safest cities, yet a hidden menace lurks beneath its streets – antiquated and deteriorating water pipes waiting to burst at any moment.

This past Tuesday morning, a burst underground water pipe on Tung Tau Tsuen Road in Wong Tai Sin led to a road depression that trapped a passing double-decker bus, with its right middle and rear tires stuck in the sunken tarmac. While fortunately no injuries occurred, the incident highlighted the growing safety hazard posed by Hong Kong’s ageing water infrastructure.

The road closure due to the burst has affected multiple bus routes and drivers. This is just the latest in a seemingly endless series of pipe bursts plaguing the city. According to the Highways Department, 17 road depression cases were reported last year, spiking to 29 in just the first 8 months of 2022. Notably, cases caused by burst or leaking water pipes and damaged drainage pipes numbered 10 last year but have already reached at least 12 from this July to present.

A burst underground water pipe on Tung Tau Tsuen Road in Wong Tai Sin led to a road depression that trapped a passing double-decker bus yesterday.

The evidence clearly shows Hong Kong’s water pipes are in an advanced state of decay, directly impacting traffic safety. This week’s trapped bus resulted in only minor inconvenience, but who can guarantee such good fortune always? Should a burst provoke a large, deep sinkhole, vehicles falling into the abyss and serious injuries or fatalities could well occur. Just this July, a burst underground pipe at Tai Pak Tin Street and On Chit Street in Kwai Chung created a gaping 5m x 5m cavity – a sobering reminder that collapses from burst pipes are no trivial matter.

Adding insult to injury, ruptured pipes not only endanger road users but also disrupt fresh water supplies. Water pipe bursts leaving homes without toilet flushing are a nuisance familiar to every Hong Kong household, sometimes occurring multiple times in a single month. However, fresh water main breaks are far more than a trivial irritation. This March, a burst fresh water pipe near Lei Shu Road in North Kwai Chung necessitated emergency repairs and a 10-hour suspension of supply affecting 300,000 residents across over 10 public housing estates. With elderly and infants forced to haul water on foot as Water Supplies Department tankers proved inadequate, daily activities like cooking, bathing, and drinking were extraordinarily arduous – essentially inhumane conditions. Additionally, multiple Sha Tin estates in 2014 saw asphalt particles contaminate fresh water supplies. The Water Supplies Department later determined this resulted from local pipe bursts and repair works where sudden pressure changes post-restoration, exacerbated by aged pipes, caused asphalt lining to peel off and enter the water system. The scale of the aged pipe problem and its threat to clean water make the risks crystal clear.

To its credit, the government recognises the gravity of the situation. Since 2000, the Water Supplies Department has implemented a Water Network Renewal Programme encompassing four phases to replace and rehabilitate around 3,000 km of ageing water mains. This 15-year, HK$23.6 billion endeavour was completed in 2015 but proved inadequate. More recently, the department has adopted a risk-based pipe asset management strategy to continually assess and repair or renew higher risk mains. However, as legislators have pointed out, current burst and road depression statistics are just the tip of the iceberg in reflecting public experience, with bursts every few days a norm across districts. The solution lies not in endless piecemeal repairs but decisive action – be it completely closing or suspending supply on entire streets for a week to comprehensively rectify underlying issues.

As a highly developed city much like its international peers, aged pipes are an inevitable challenge Hong Kong must confront head-on. In today’s smart city era, the Water Supplies Department should consider more preventive, intelligent monitoring while re-engineering connections with backup secondary and tertiary conduits. Decisive action is overdue to defuse this ticking time bomb beneath Hong Kongers’ feet.

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