Water Corporation concludes ‘external corrosion to the underside of the pipe’ caused Spearwood sewer burst

Months after foul smells filled the air in Spearwood and human waste inundated homes, parks and businesses, the Water Corporation has finally revealed what caused the disastrous burst sewer main that forced locals to flee their homes. The Water Corporation this week confirmed to The Sunday Times that the June 6 Hamilton Road pipe burst — which triggered a chain reaction of sewage spills across Perth’s southern suburbs — was caused by “external corrosion to the underside of the pipe.” “With respect to the initial burst on Hamilton Road, Spearwood, corrosion was caused by a combination of acidic gases within the pit, and moisture including from rain and humidity,” a Water Corporation spokesperson said. “Two sections of cement mortar lining were analysed, with the top section found to be deteriorated within expected tolerances. This supports the conclusion that external corrosion was the ultimate cause.” What began as a single burst pipe on Hamilton Road — flooding front yards and multiple homes — quickly spiralled into a wider crisis when efforts to divert the flow of waste caused a second rupture in Beaconsfield the next morning. That failure sent sewage surging through local parks and residential areas including Alfred Cove, Applecross, South Fremantle, Fremantle Harbour and parts of the Swan River. The pipe took four days to repair, with crews working around the clock as the stench lingered across suburbs. Many residents chose to stay elsewhere to escape the foul smell. Turf had to be replaced at Bruce Lee Reserve in Beaconsfield and Kitj Park in Spearwood, both of which required extensive decontamination before sports resumed. Matches did not return to Bruce Lee Reserve until after July 21. A section of wastewater pipe at the corner of Caesar Street and Grosvenor Road in Beaconsfield took more than two months to fix. “To isolate the burst on Hamilton Road, wastewater flows from nearby pump stations were diverted to other areas of the network,” the spokesperson said. “This caused increased pressure in the pipe which later failed on Caeser Street, Beaconsfield.” The incidents raised concerns about the condition of WA’s ageing water infrastructure — with some sections of the network more than 120 years old. “While we do have older sections of pipe, the condition of the pipe rather than its age is a more reliable indicator of potential issues,” a Water Corporation spokesperson said in July. “Newer pipe can fail prematurely in adverse environmental conditions and older pipe can continue to operate reliably for decades with an appropriate inspection regime.” The corporation spent $30.25 million maintaining Perth’s wastewater network in the last financial year — $1.2m less than the year before but almost $10m more than five years ago. “Maintenance investment on water and wastewater networks will be bolstered this financial year through a $35m uplift allocated under the 2025-26 State Budget,” the spokesperson said. “We expect to spend around $100m on water and wastewater renewals in Perth this financial year. This is one of our largest ever annual spends on renewals in the metro area and is supported by an $80m uplift over two years allocated under the 2024-25 State Budget.” Minister for Water Don Punch was contacted for comment but did not respond. Shadow water minister Peter Rundle said he had concerns over the ageing infrastructure of the water network. “I don’t think it’s acceptable that people are left in the dark to some extent and the inconvenience that was caused,” he said.