The CON29DW explained – Building over a public sewer

Our series looking at issues raised by the CON29DW examines the consequences of building over, or near to a public sewer.

Question 2.7 of the CON29DW asks ‘Has a Sewerage Undertaker approved or been consulted about any plans to erect a building or extension on the property over or in the vicinity of a public sewer, disposal main or drain?’

Whilst it may seem strange for the CON29DW to ask if water companies are consulted on such matters, it’s standard practice with planning applications. The planning and building control departments of local authorities will routinely consult water companies when any proposed application is in the immediate vicinity of one of their assets. Furthermore, smaller developments not requiring planning permission will also need to be approved by water companies if it is likely to impact on their assets.

The reason for this is simple. The public water and sewer networks are vital, and it’s important that water companies can access their assets at any time, and that these assets are not obstructed or damaged by building work. And whilst they’re not as strict with restrictions around sewers as they are around water mains (where building over/close to is outright forbidden) they will use their statutory powers to protect their assets.

It’s not just to protect the sewers however. Building too close to a pipe could have a negative effect on your property. Although uncommon, a damaged sewer near a property can lead to flooding or, in extreme cases, parts of a building collapsing.

Every water company has slightly different rules around what is and isn’t permitted. Severn Trent’s are detailed on this page of their website. As a general rule, any development within three metres of a public sewer will need some kind of consent from Severn Trent. There’s usually a fee involved to process the request, which varies depending on the size of sewer and complexity of the development, and Severn Trent may require additional steps taken, such as a CCTV survey prior to granting permission.

With formerly private sewers (such as those which transferred into public ownership in the 2011 sewer transfer) usually no formal consent will have been granted by the water company, as it would not have been necessary at the time. Severn Trent’s general position on this is that, providing proper procedures were followed (such as obtaining planning permission where necessary), they will have no objection to any build overs.

If a sewer has been built over or near-to without the water company’s permission, the company has full legal powers to take whatever steps it considers necessary to protect their assets. This can be anything from an on-site inspection, to making the owner pay to divert the sewer or in extreme cases, removing the building built over their asset.

It’s primarily for this reason that the information’s included in the CON29DW. Water companies will hold the current owner of a property responsible for unapproved developments, regardless of whether they were the owner at the time. It’s best to check prior to purchasing a property whether all development work was approved, including around sewers, so it doesn’t cause any issues down the line. When consent is granted by water companies, they will often be the only source of this valuable information.