If your project involves building over or near our sewer pipes, you’ll usually need our approval before you start. Because we look after public sewers, it’s important we review your plans to keep your home and our network safe.
We can’t grant approval retrospectively, but don’t worry - our team is here to guide you through the process so you can move forward with confidence.
Not all public sewer pipes appear on maps
Since October 2011, many private sewers have been transferred to local water companies, meaning we now maintain most shared drains and sewers across our region. However, most of these pipes don’t appear on maps. Water UK offers helpful guidance on which pipes became public and which remained private.
Permitted development projects
Even if you have planning permission or your project falls under Permitted Development, you ‘ll still need our permission to build over or near a sewer so you should still check for nearby sewer pipes. Utility locations aren’t covered in the planning process, that’s why requesting or viewing a sewer map before starting work can give you a rough idea of sewer pipes that are on your land.
When you need permission to build over or near our sewers
You’ll need our permission to build over or near a public sewer if your project:
We may not always be able to permit building over or near a public sewer in the situations listed above, so getting in touch with us early is really worthwhile – especially if the sewer is 300mm in diameter or over. It can help you avoid unexpected planning or architect fees and ultimately save you both time and money.
What is a protective strip?
A protective strip is the clear space that must be kept around a public sewer so it stays safe and easy to get to for maintenance. This area is measured from the centre of the sewer pipe, and the size of the strip depends on the diameter of the sewer:
Formal build over agreements
A Formal Build Over Agreement is written permission that allows you to build over or close to a public sewer that runs near or underneath your property. The agreement confirms that your plans are acceptable, safe, structurally sound and won't damage or restrict access to the sewer now or in the future.
You’ll need to use our Formal Build Over Application if the sewer is larger than 150mm, if you need to move, alter, or build over a manhole, or if your project doesn’t meet the requirements for self‑certification.
Here’s how it works:
Send us your application, building plans, CCTV survey (if you’re not replacing the pipe), and pay the application fee.
We’ll thoroughly assess your application and make sure that your payment has been received. This takes up to 10 working days.
If approved, we’ll send you a letter with any conditions that need to be met in order to keep the sewer and your property safe. If not, we’ll explain why and how to adjust your plans if it’s possible to do so. If it’s not possible, we may need to reject your application.
You can start work once you’ve received approval from us and your building inspector.
After you’ve finished your work, send us a CCTV survey report to show that the sewer has remained structurally acceptable and that any conditions outlined at the provisional approval stage were met.
If everything's gone to plan, we'll send final approval. If not, we'll explain what needs fixing - any extra costs needed to put things right will need to be covered by you.
Read our supporting guidance
We have lots of helpful supporting guidance if you’re planning to build over or near a public sewer.
Apply to build over or near our sewer
Once you know whether you need a formal agreement or you’re able to self-certify your project, you can apply for our approval to build over or near a sewer.
If you need help finding the right application form to use, get in touch with our team - they're here to help.