Build-Over Agreements London, Surrey & Hampshire. Hassle-Free Approvals.
Planning an extension over or near a public sewer? We provide the essential pre- and post-build CCTV drainage surveys and documentation required to secure your build-over agreement with the local water authority.
Why Choose Us?
- Water authority compliant reports
- WRC approved CCTV surveys
- Pre-build & post-build mapping
- Fast turnaround for planning
What is a Build-Over Agreement?
If you are planning to build an extension, conservatory, or new structure within 3 metres of a public sewer, you are legally required to obtain a build-over agreement from your local water authority (such as Thames Water).
The water authority needs to ensure that your new building will not damage the sewer, and that they will still have access to the pipes for maintenance and repairs. To prove this, you must submit a detailed CCTV drainage survey before and after the building work.
Pre-Build CCTV Survey
We map the exact location, depth, and condition of the sewer before any work begins.
Detailed Reporting
You receive a WRC-approved report, site plan, and video footage to submit with your application.
Post-Build Verification
Once construction is complete, we perform a final survey to prove the sewer remains undamaged.
The Agreement Process
- 1
Initial Survey
Our engineers conduct a comprehensive CCTV drainage survey to map the public sewer lines on your property.
- 2
Application Submission
You submit our detailed reports and footage to your local water authority alongside your architectural plans.
- 3
Construction Phase
Once approved, your builders can safely construct the extension following the agreed guidelines.
- 4
Final Sign-Off
We return to conduct a post-build CCTV survey, proving to the water authority that the sewer is intact, allowing them to issue the final certificate.
Frequently Asked Questions
Common questions about build-over agreements.
Do I always need a build-over agreement?
If your planned extension or new building is within 3 metres of a public sewer, yes. It is a legal requirement. If you build without one, the water authority has the right to tear down the structure to access their pipes.
What happens if I don't get one?
Building without an agreement can cause major issues when trying to sell your property, as the buyer's solicitor will request the documentation. You may also be liable for any damage caused to the public sewer.
How long does the CCTV survey take?
A standard pre-build CCTV drainage survey for a residential property usually takes between 1 to 2 hours. We provide the reports and footage shortly after completion so you can submit your application without delay.
Can you guarantee the water authority will approve it?
While we cannot guarantee approval (as that depends on your architectural plans), we guarantee that our CCTV drainage survey reports meet the strict WRC standards required by all UK water authorities, including Thames Water.