As has been widely reported in the media, on 17 February a large sinkhole opened up on a street in Godstone, Surrey, leading to the evacuation of 30 households as a precautionary measure due to fears of further ground instability and potential gas explosions. We understand residents have been informed that they may be unable to return to their homes for up to eight months as structural assessments and stabilisation work continues.

Any household insurer whose customer’s property may have been damaged will be keen to understand the cause of the sinkhole; and rights of recovery might be available in respect of damage or alternative accommodation for example.

We asked David Mumford, Technical Director of OTB Engineering Limited, what could have caused the sinkhole:

“The recent sinkhole in Godstone, Surrey, is similar to many historical cases observed across the UK, which are often associated with factors such as historical land use, erodible ground conditions, and uncontrolled water sources.

In this case, potential causes may include a burst water main beneath Godstone High Street, which could have led to soil erosion and loss of support within the underlying strata. If this occurred, pressurised water escaping from the pipe could have mobilised fine materials, creating voids that progressively collapsed under loading.

The underlying geology of the area, predominantly the Folkestone Formation, consists of weakly cemented sandstones, which are highly susceptible to erosion when exposed to water flow due to their relatively high permeability. Additionally, Godstone has a long history of sand mining, dating back to the 17th century. Many of these workings are unrecorded, increasing the likelihood that voids exist beneath the surface. A sudden influx of water from a burst pipe could have reactivated an old mine, leading to the observed ground failure.

A comprehensive forensic investigation, typically including geophysical surveys, boreholes, and trial pits, should be undertaken to establish the cause(s) and inform appropriate remedial measures.”

Until the comprehensive forensic investigation is complete, any household insurer exposed will be unable to fully consider any recovery options or prospects they may have. However, if it transpires that the sinkhole was caused by, or contributed to by, an escape of water from a fresh water main, insurers who indemnify in respect of property damaged as a result of the sinkhole may well have a right of recovery against the appointed water company for the area pursuant to Section 209 of the Water Industry Act 1991.

That legislation imposes strict liability on the water company for damage arising from an escape from a fresh water main, without the need to prove negligence and regardless of the cause of the escape (subject to limited statutory defences). Unlike some statutory liabilities, insurers are entitled to pursue subrogated recoveries under Section 209.

It is worth noting that “pure economic losses” – that is, losses not resulting from property damage – are likely not recoverable under Section 209. So there may be no recovery where, for example, costs are incurred for alternative accommodation for residents evacuated on a precautionary basis but whose property has not been damaged. It will therefore be necessary to establish whether property damage has occurred.

Of course, any insurer would have to investigate the cause of the sinkhole before deciding upon the best course of action regarding recovery options. Our specialist property teams are highly experienced in this type of case and for further information or advice on any property damage related insurance issue, contact tom.davison@h-f.co.uk

With thanks to David Mumford, Technical Director of OTB Engineering Ltd for his contribution to this article.