In the recent decision in the case of Northumbrian Water Limited (“NWL”) v McAlpine Limited (“McAlpine”) [2014], Moore-Bick LJ provided the leading judgement (upholding the first instance judgement) that the contractor, McAlpine, was not liable for concrete entering and blocking a sewer during the course of construction works.

This case does not provide any new legal interpretations but does illustrate the courts’ somewhat softer side to the difficulties faced by contractors during construction projects.


In 2008, McAlpine was carrying out works as part of a development on Newgate Street in Newcastle. McAlpine’s sub-contractor poured concrete to create a piled foundation, however, at some point during this process some of the concrete escaped into the sewer, unknown to anyone involved at the time. A few weeks later the Co-op, a neighbouring business, contacted NWL complaining that sewerage was backing up into its premises.

NWL undertook extensive investigations and discovered eventually, through hours of research in the archives of the Discovery Museum in Newcastle, that there was a private drain near to where the concrete pour had occurred. This was discovered on a 1908 plan which showed a private drain in that area. At this point, it was revealed that the concrete had, in fact, entered the public sewer via this private drain. NWL removed the concrete from the sewer and sought to recover the cost (some £300,000) from McAlpine, arguing claims both in negligence and nuisance; but principally that McAlpine had been negligent in failing to carry out sufficient investigations before starting works.

Negligence and Nuisance

In order to succeed with a negligence claim, NWL would have to show that McAlpine failed to take reasonable care to identify other drains and services in the area before starting works. McAlpine argued that it had carried out extensive research, including ground surveys and discussions with utility companies, as well as scans and trial pits and had also relied on details supplied by NWL. In addition, as the site had been extensively developed in the 1970s, McAlpine argued it was entitled to assume that private drains would have been removed as part of that development. The obligation on McAlpine was to take reasonable care to identify utility services in the area.

The judge held that he felt it was right to agree with the judge at first instance that “a reasonably competent and careful contractor would not search local museum archives for several hours to ascertain whether a drain had existed from some hundred years earlier”. McAlpine had taken reasonable care and was not negligent in relation to failure to investigate the presence of the private drain and NWL’s losses were not reasonably foreseeable.

NWL also claimed in nuisance. However, as this again relied on the existence of this private drain being reasonably foreseeable, the judge held that the claim in nuisance also failed.

The judge also considered the ruling Rylands v Fletcher where a defendant can be liable for escape of something he has brought onto his land which “causes mischief if it escapes”. However, again the judge concluded that since the existence of the private drain was not reasonably foreseeable, damage to the public sewer was not a reasonably foreseeable consequence from the escape of any concrete.

The case offers some reassurance to those in the building industry that where reasonable care has been taken to carry out the necessary investigations prior to commencing works, the law will not seek to impose liability on them for problems which could not have reasonably been foreseen – having undertaken all reasonable investigations.