Section 185 – Essential Information

A Section 185 Sewer Diversion Agreement is necessary if a public sewer crosses a proposed site of works, and the developer submits a request to undertake a reasonable diversion of the sewer.

Section 185 explained

  • Under Section 185 of the Water Industry Act 1991, a builder or developer can request that a public sewer is altered, diverted, or removed to allow a site to be developed. Where a public sewer crosses a site, a developer can submit a request to the water authority to undertake a reasonable diversion of it.
  • Developers with an interest in land that contains a public sewer can request the diversion of the sewer to allow development work to progress, following section 185 of the Water Industry Act 1991.
  • The developer may be able to carry out the diversion themselves. However, if it is a complicated situation, such as a strategic sewer, the water authority may have to carry out this work. In all cases, charges apply.
  • Section 185 places a duty on the water authority to divert apparatus in land, upon receipt of notice from persons who have an interest in the land, as necessary to enable that person to carry out a proposed improvement of the land. This duty does not arise when apparatus is located in, under or over any street.

How long does a Section 185 agreement take?

Diversion of public sewers under Section 185 of the Water Industry Act 1991 can be a protracted process. All parties involved (developers, consultants, contractors, project managers) need to be aware of the process, costs, legal and technical requirements, and programme implications.

Developers need to ensure that sufficient time has been included in their build programme for diversion of sewers before works associated with the development commences.

Premier Drainage Solutions are experienced in undertaking paperwork on behalf of clients dealing with water authorities. Our experience in this field means we can give a realistic estimate of how long it will take to get a licence or agreement which benefits clients’ planning processes. A typical mistake we often see is developers not factoring in enough time for paperwork, then needing to put a site on standby while they wait for approval. If you’re not sure of the timescales, contact us and we’ll be happy to help.

Who carries out the work?

The developer may be permitted to carry out the work when:

  • the sewer is non-critical infrastructure and/or diversion is solely in land owned by the developer.

The water authority will help determine how the diversion will be delivered:

  • as part of a Section 104 Agreement constructed by the developer in conjunction with adoptable sewers.
  • as a minor sewer diversion, constructed by the developer subject to an exchange of letters.
  • as a major sewer diversion, constructed by the developer under the supervision of the water authority, or the water authority itself, and supported by a S185 legal Agreement.

With either option, a Section 185 legal Agreement must be signed before turning flows at either end of the diversion.

Once the existing sewer flows have been diverted into the new pipework, the redundant sewer must then be abandoned in accordance with the developer’s Method Statement.

What happens during construction?

  • During construction, water authority inspectors will attend the site to monitor work being undertaken on site concerning the diversion of water authority assets.

What happens after construction?

  • When the diversion is complete, along with any additional work, it is the developer’s responsibility to provide the water authority with ‘as built’ drawings for the works undertaken. A copy of all the drawings included within the signed S185 Agreement must be provided in ‘as built’ format.
  • When the flows have been turned, you can request a pre-maintenance inspection.
  • Within three months of the end of the site maintenance period, if there have been no operational issues and there are no outstanding additional works to complete, you can prepare for a final inspection.
  • The sewer to be abandoned must be clearly indicated on the drawings submitted for approval and the method of abandoning the sewer must be stated.

What do I need for a Section 185 application?

Check with your relevant water authority for specifics. Usually, for a Section 185 application, you will need:

  • Location plan
  • S185 layout plan
  • Longitudinal sections
  • Manhole schedules
  • Construction details
  • Camera survey
  • F10 notice
  • Hydraulic calculations
  • Any additional information that would support your application.

Premier Drainage Solutions are experienced in working with Thames Water, Southern Water and Anglian Water. Let us take the headache out of water authority planning and paperwork for you. Get in touch to see how we can help.

Sources: Yorkshire Water – Sewer diversions, Thames Water, Southern Water and Anglian Water

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