Diverting a public sewer

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Developers with an interest in land that contains a public sewer can request the diversion of the sewer to allow development work to progress, in accordance with section 185 of the Water Industry Act 1991. Often you can do the diversion work yourself, but sometimes we’ll need to - for example, if it’s a strategic sewer that’s being diverted. Charges will apply in all cases. If you need a diversion you should apply using the button below, and we’ll advise you on the next steps.

Apply to divert a public sewer

For details on how we’ll use the information you provide in your application, click here.


  1. You submit your application.
  2. We carry out a technical review to determine if the sewer is strategic in nature. If it’s a non-strategic sewer you may be able to do the work involved. In this case:
  3. Within 14 days of receiving your application, we'll let you know if we need any more information. Once we have everything, within 28 days we'll send you our technical decision and what you need to do next.
  4. If the work is approved, you'll need to sign the legal agreements that need to be in place before work on the sewer(s) can start.
  5. You notify us when the diversion is due to take place.
  6. Our field engineer periodically inspects the works and lets you know any corrective actions required.
  7. When you’ve finished, you provide as-built drawings and CCTV surveys so that we can update our records and ensure construction has been carried out satisfactorily. We let you know if any corrective works are needed.
  8. Once any remedial work has been completed, we issue a provisional vesting certificate.
  9. After a one year maintenance period and our final inspection, we issue a final vesting certificate and adopt (take responsibility for) the sewer(s).

If it’s a strategic sewer we’ll generally do the work. In this case:

  1. Within 5 days of receiving your application, an engineer contacts you to discuss your application and request further information if necessary.
  2. Next, our engineer undertakes a preliminary investigation to identify a diversion proposal. Our engineer then discusses the proposal's impact on the catchment with our network operations and asset planning departments.
  3. If there are no objections, within 5 weeks of the proposal a budget estimate and indicative programme are produced. At this stage, if circumstances allow it, we discuss you doing the work under a section 185 agreement.

Need to pay us?

Please click here if you've already applied and need to make a payment.