Sewer diversions

Where a public sewer crosses a site, a developer can submit a request to us to undertake a reasonable diversion of it.

Rippling water

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 us to undertake a reasonable diversion of it.

Section 185 places a duty on Yorkshire Water 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.

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.

Legal and financial arrangements differ depending on who carries out the works.

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

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

We can help determine how the diversion will be delivered, either:

  • 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; or
  • as a major sewer diversion, constructed by the developer under our supervisions or Yorkshire Water (constructed by one of our contract partners) 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.

Minor Sewer Diversion

The procedure for applying for a minor sewer diversion is outlined below, along with the relevant forms for completion

Any diversions to the public sewer network shall not be commenced until the S185 legal Agreement with Yorkshire Water is in place.

During construction, our inspectors will attend site to monitor work being undertaken on site in relation to the diversion of our assets.

The sewer to be abandoned must be clearly indicated on the drawings submitted for Technical Approval and the method of abandoning the sewer (i.e. removed, grouted, fly ashed etc) must be stated.

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.

Apply online

Our online application form is the quickest and easiest way to apply.

Apply online

You can also download and print this PDF or fill it out using Adobe Acrobat Reader.

You can download our health and safety sewer diversion request form (S185).

Stage 1: Application and Assessment

To submit an application, you can either download a form or make an application online. Once you have submitted your completed application form, proposed drawings and camera survey, we will technically assess your submission and provide an initial response detailing whether the proposals are acceptable or not.

Apply online for a sewer diversion

You can also download and print this PDF or fill it out using Adobe Acrobat Reader.

Stage 2: Diversion Agreement

Any diversions to the public sewer network shall not be commenced until the S185 legal Agreement with Yorkshire Water is in place.

Stage 3: Construction

During construction, our inspectors will attend site to monitor work being undertaken on site in relation to the diversion of our assets.

When the diversion is complete, along with any outstanding remedial work, it is your responsibility to provide us 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.

Stage 4: Maintenance Period

When the flows have been turned, you can request a Pre Maintenance inspection. Please download, complete and return this request form to us along with supporting information.

Pre-Maintenance Request Form for Sewer Diversion

You can also download and print this PDF or fill it out using Adobe Acrobat Reader.

Stage 5: Final Inspection

Once your site is within three months of the end of its maintenance period, has been operating as expected during this time (with no operational issues) and there are no outstanding remedial works to complete, you can start to make preparations for the Final Inspection.

If you would like to request a Final Inspection of your site, please download, complete and return this request form to us along with the supporting information.

Final Inspection Request Form for Sewer Diversion

You can also download and print this PDF or fill it out using Adobe Acrobat Reader.

Major Sewer Diversion (Developer Led)

Where a large diameter (or critical) public sewer crosses a site, a developer can submit a request to us to undertake a reasonable diversion of it. We encourage you to engage in early discussions with us so we can guide you through the process requirements whilst ensuring the performance and longevity of the altered or diverted sewer is not compromised.

We are happy to meet with you at the outset of the process, prior to submission of a complete application, to ensure our requirements are clear and any issues with a site can be discussed at an early stage.

Any diversions to the public sewer network shall not be commenced until the S185 legal Agreement with Yorkshire Water is in place.

Application for a major sewer diversion or alteration (developer led)

You can download and print this PDF or fill it out using Adobe Acrobat Reader.