Build over drain surveys
CCTV Build over drain surveys for pre- and post- construction requirements, with WRC-approved reporting, drainage mapping and evidence suitable to support water authority build over applications.
✔ Pre-build over surveys
✔ Post- build over surveys
✔ Build near surveys
✔ Reports for water authority submission
When you need a build over survey
A build over drain survey is typically needed when:
Building an extension - if your extension is being built over or close to a public sewer or shared drain, a build over agreement is usually required, with a CCTV drain survey needed to support the application.
Structural alterations - if carrying out work within the vicinity of or over a public sewer or shared drain
Projects affecting shared or public sewers- if you intend to reroute or divert a public sewer or drain, the water authority will need to be notified.
Before approval is granted, the condition of the drainage system must be assessed to ensure it can support the proposed works. Requirements vary by water authority but are generally required when building over or within 3 metres of a public sewer or shared drain, served by United Utilities or Severn Trent.
What does a Build over Drain Survey include?
We use high-definition CCTV equipment to inspect your drainage system internally. This allows us to assess condition and suitability.
You receive:
A full WRc-approved drainage survey report
Complete condition assessment with MSCC5 coding
Annotated drainage map
High definition CCTV footage and images
Clear identification of any issues
Information to support your build over application
Whether the drain or sewer is suitable for build over
Pre-build vs post-build survey
Pre-build drain survey
A pre-build CCTV drain survey is carried out before construction starts to establish the existing condition and route of the drainage. This provides a clear record of any defects already present and helps confirm whether the proposed works could affect public or shared drainage.
The survey typically includes CCTV footage, condition reporting and drainage mapping, giving you the evidence needed to support a Build over or Build near application.
Post-build drain survey
A post-build drain survey is carried out once construction is complete to confirm that the drainage remains in satisfactory condition and has not been damaged during the works.
Where required, the post-build report can be used as part of the final sign-off process, providing updated CCTV evidence and confirmation of the condition of the affected drainage.
How much does a build over drain survey cost?
The cost of a Build over drain survey depends on the size and complexity of the drainage system, the number of access points and whether a pre-build, post-build or combined survey is required.
For a typical residential property, our Pre-build over drain surveys start from £275+VAT, with post-build surveys quoted seperately or part of a combined package.
Your quotation will confirm exactly what is included before the survey is booked. This will typically cover:
CCTV inspection of the relevant drainage
MSCC5-coded condition reporting
Drainage asset mapping
Supporting images and CCTV footage
Identification of structural defects or issues requiring attention
Recommendations where remedial works are needed
Where both pre- and post- build surveys are required we can provide a combined quotation for the full survey process.
How does the Build over drain survey process work?
We keep the process straight forward from booking through to final reporting.
Send us your project details - Provide the property address, proposed works and any drainage plans or information you already have.
We confirm the survey scope - We’ll review what is required and confirm whether you need a pre-build survey, post-build survey or both.
We carry out the CCTV survey - Our engineer attends site to inspect the relevant drainage, record the condition of the pipework and map the route of the system where required.
We prepare the report - You’ll receive a clear WRc-approved report including CCTV findings, MSCC5 defect coding supporting images and drainage mapping.
Use the report to support your application or sign-off - The report can then be submitted with your Build Over or Build Near application, or used as post-construction evidence where required.
Where defects are identified, we’ll also explain the issue clearly and recommend any remedial works that should be completed before the project progresses.
Past Projects
Examples of build over drain surveys carried out across Cheshire, Manchester and Staffordshire.
Build over drain survey in Stoke-on-Trent, Staffordshire.
Post-build drain survey in Mobberley, Cheshire
Build over drain survey in Warrington, Cheshire.
Build over drain survey in Meir, Stoke-on-Trent, Staffordshire.
Pre-build drain survey in Altrincham, Manchester.
Build over drain survey in Stoke-on-Trent, Staffordshire.
Why choose Clearflow Surveys?
Build Over surveys need to do more than simply produce CCTV footage. They need to provide a clear reliable record of the drainage condition and give you the information required to move the project forward.
Clearflow Surveys provides:
WRc-coded condition reports with clear identification of defects and their severity
Drainage mapping showing pipe routes, flow direction and key access points
HD CCTV footage and supporting images from the survey
Pre-build and Post-build surveys for Build over or Build near requirements
Experience inspection shared, private and public drainage
Practical recommendations where defects or remedial works are identified
Clear reporting designed to be easy for homeowners, architects, contractors and water companies to understand.
Helpful build over guidance
Frequently Asked Questions
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A build over survey is a CCTV inspection of the drainage system carried out before, during or after construction work near or over an existing shared drain or sewer. It records the condition of the pipes so there is a clear record of what they looked like before the work began.
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If your extension is being built near or over a public sewer, your water company will almost certainly require one as part of their build over agreement process. Even if it isn’t required, it protects you - it establishes a baseline so you can’t be held responsible for pre-existing damage if questions arise later.
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Your architect or structural engineer may already know, but if not, a drainage map from your water company will show the location of public sewers on or near your property. We can also advise based on what we find during the survey.
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We carry out the CCTV survey and provide you with the report you need. The build over agreement application itself is submitted to your water company - usually by your architect, builder or solicitor. We’ll make sure the report gives them everything they need to support that process.
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Ideally before construction begins, so there is a clear record of the drain’s condition before any work takes place. A post-construction survey is also often required to confirm no damage occurred during the build. We can carry out both.
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You receive a full WRc-approved CCTV drainage survey report including condition assessment, high definition footage and images, with clear recommendations. It’s formatted to meet the requirements your water company expect.
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The survey itself typically takes one to two hours on site. Your report will follow shortly after, so it won’t hold up your project timeline.
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If we find existing damage before construction starts, that’s actually useful - it means you’re not liable for it later. We’ll set out clearly what’s been found and recommend next steps so you can deal with it before work begins.