Should the location of a public sewer prevent land development or a property extension, it may be possible to build over the sewer in accordance with the Building Regulations 2000.

However, this will be subject to our approval.

For all sewer classes, except class one domestic, we will need to carry out a survey. This is usually undertaken by Closed Circuit Television (CCTV).

How to apply for public sewer build over

You can apply to build over a public sewer in the following ways:

Download an application form

Click the link below to download and fill in an application form.

• Building over a public sewer application (0.09Mb)

Guidance notes

Please refer to our guidance notes before completing your application.

• Building over a public sewer guide (0.07Mb)

There are standard fees for this service based upon the size of sewer affected.

How much we charge for building over a public sewer

Our standard fees for building over a public sewer:

Class	Diameter	Typical builds	Cost
Class I	Up to 160mm (6")	Domestic extensions	£343
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

A minimum deposit of £1,300 will be charged against actual costs incurred.

Need help with your application?

For enquiries relating to your Building Over Application form please contact our Developer Services helpdesk on 0845 850 2777, and one of our agents will be happy to answer any questions you might have.

Our lines are open from 8am to 5pm, Monday to Thursday, 10am to 5pm on Fridays and are closed at weekends and bank holidays.

Request an Asset Location Search

Our Property Searches team can provide an Asset Location Search that provides information on the location of Thames Water's clean and/or wastewater assets, including pipe sizes, depth information (cover and invert levels) and direction of flow.

This product is available for a cost of £55.20 (inc VAT), and you will receive your search within five working days.

If you need an Asset Location Search sooner than this, then we offer the option of delivery within one working day, at a cost of £109.92 (inc VAT).

Get in touch

To order our services online or to find out more about Thames Water Property Searches, visit www.thameswater-propertysearches.co.uk or call our customer service team on 0118 925 1504.

Our lines are open between 8.30am and 5pm, Monday to Friday, and closed on weekends and bank holidays.