BCA to start independent investigations into Tanjong Katong sinkhole incident
Investigations could take several months, given the complexity of the incident, said the Building and Construction Authority.
The sinkhole along Tanjong Katong Road South on Jul 27, 2025. (Photo: CNA/Ili Mansor)
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SINGAPORE: The Building and Construction Authority (BCA) said on Monday (Jul 28) it is starting an independent investigation into the Tanjong Katong sinkhole incident, now that the ground situation has been stabilised.
“The investigation will examine the circumstances leading to the formation of the sinkhole, identify the root causes, and take the necessary actions against any non-compliance under the Building Control Act and Regulations,” BCA said in a media statement.
The agency said investigations could take several months, given the complexity of the incident.
“It will include detailed geotechnical analysis and other validation tests by BCA and its appointed consultants,” BCA added.
The sinkhole appeared along Tanjong Katong Road South on Saturday evening, causing a car to fall in. The female driver was rescued by workers and taken conscious to Raffles Hospital.
BCA said that since the incident, its engineers have been conducting round-the-clock site monitoring to ensure that surrounding buildings, roads and infrastructure remain structurally safe.
The sinkhole, which was about 2m to 3m deep, is adjacent to an active PUB worksite involving the construction of a 16m-deep shaft connecting three existing sewer lines.
Providing a timeline of what happened, PUB said on Sunday that a concrete component in the shaft failed at around 5.50pm on Saturday.
At around the same time, a sinkhole formed on the adjacent road.
PUB said it was still not clear what contributed to the failure of the component.
The national water agency said the shaft has since been backfilled to stabilise the surrounding ground. The sinkhole has also been filled with liquefied stabilised soil to further stabilise the area. Both measures were completed early on Monday morning.
“As a precautionary measure, BCA had recommended that PUB implement a safety time-out for similar sewer construction projects across Singapore, and conduct a thorough review of current practices and safeguards at these worksites,” said the building authority.
Tanjong Katong Road South between Mountbatten Road and East Coast Parkway (ECP) will be closed until further notice for repairs, the Land Transport Authority said on Sunday.
Bus services 36 and 48 have been diverted.
