Apply to build over or near a sewer

When you need our approval

If you’re building within three metres of a public sewer, or within one metre of a public lateral drain, you’ll need our approval before you start work.

The two types of build over agreement

If you’re building over or near a domestic sewer with a diameter of 160mm or less, you can potentially apply for a self-certified build over agreement. We may grant this if you’re able to confirm that your plans pose little risk to the pipe.

If your answers meet our requirements, we’ll send you an agreement. If not, we’ll redirect you to apply for an approved build over agreement, for which you’d need to pay. You’ll need to apply for this approved agreement if you’re unsure of any of the answers, or if you want to build over or near a sewer with a diameter above 160mm.

Apply for a self-certified build over agreement

Please click below to answer our online questionnaire and find out whether you qualify for a free self-certified build over agreement.

Please note, there are a number of reasons you might not qualify. For example, you will NOT qualify if:

  • there are manholes serving other properties within the footprint of your new building or within half a metre of it,
  • you’re building a new property,
  • you’re aware of any smells, blockages or flooding in the last five years, or
  • the sewer has holes or cracks in it.

Apply

Apply for an approved build over agreement

If you can’t confidently answer any of the questions in our online questionnaire, or know that you don’t qualify, you’ll need an approved build over agreement. There is a charge for this, although we offer a discount if you apply online.

You can apply online below, or by completing our PDF application form.

For all sewer classes, except class one domestic, we will need to carry out a survey using Closed Circuit Television (CCTV). There are standard fees for this service based upon the size of sewer affected.

Our fees for building over a public sewer are listed in the table below.

Class Diameter Typical builds Cost
Class I Up to 160mm (6") Domestic extensions £343 by email or post / £299 apply and pay online
Class I Up to 160mm (6") Commercial / industrial / new build £687
Class II Up to 160mm (6") to 375mm (15") inclusive   £687
Class III Over 375mm (15") inclusive   £1,300 deposit

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


Any personal information that you provide will only be used to process this application. We use a third party, WorldPay, to collect all payment details and process payments made through our website.

When submitting this form, you will be redirected to WorldPay's secure server where you will be presented with a series of payment pages, enabling you to choose your payment method and enter your payment details.

WorldPay will record your payment details against the details submitted on this form, to produce a transaction.

The transaction details will be forwarded to the card issuer for authentication. The issuer will then return an authorised or declined response to WorldPay and a payment response page is then displayed to you.

If the transaction is successful, WorldPay will also send you a confirmation email, confirming the transaction details.

WorldPay accept card payments from MasterCard, Debit MasterCard, Visa Credit, Visa Debit, Visa Electron, Maestro, JCB, and Solo.

Payment or refund related enquiries

If you would like to contact us about an online payment or refund, please call us on 0800 009 3921, our lines are open Monday to Friday from 8am to 5pm. You can also email us developer.services@thameswater.co.uk.

To complete this form, you will need the following:

  • The applicant's full name, contact number and email address.
  • Property owners details (If different from applicant details)
  • The address of the property where the build over agreement is required.
  • A drawing showing the location of the sewer relative to the existing property and proposed work in PDF format.
  • A drawing showing the cross-sectional foundation plan in PDF format.
  • A copy of the drawings submitted for Building Regulations approval.
  • The size of the sewer being built over. For further support and information, please call our Property Insight team on 0118 925 1504, lines are open Monday to Friday from 8.30am to 5.30pm.
  • Credit or debit card to pay the required deposit and charges.

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About you

About the person applying

This is the person we'll contact about the application and will receive all correspondence. This can be the property owner or someone acting on their behalf.

Applicant contact details

We'll use these details to get in touch with you about your application

Applicant address details

We'll use these details to get in touch with you about your application

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(You'll need to upload proof of your entitlement on the next page.)

(You'll need to pay online after submitting this form to qualify for our online discount price of £299. Postal and email applications are priced at £343.)

Working out the cost

(You'll need to upload proof of your entitlement on the next page.)
(You'll need to pay online after submitting this form to qualify for our online discount price of £299.Postal and email applications are priced at £343.)

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Upload your documents

All drawings must be of suitable detail and have a drawing reference number on them.
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Review
Please review and confirm your details. You won't be able to submit the form until all mandatory fields have been completed

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