Where a property or part of a property is built over a public asset such as a water main or sewer, it is advisable to check that permission has been granted in the past for the building or extension to have been erected.

Whilst it is not uncommon for an extension etc. to have been erected over a main without permission (since permission has not always been required to be sought!), it is always a good idea to check. Should you have an asset under your building, there are certain risks associated, and responsibility lies with both the householder and the statutory undertaker to ensure that the risk to the asset is minimised. If the weight of the building causes damage to the sewer, it may be possible that the householder is held responsible, and similarly, if a broken sewer causes damage to foundations, it may be that the undertaker is held responsible. These cases can be problematic, but are extremely rare.