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Build Over Agreement explained, Camera Survey of my Drains, Why do you need one, Is my drain to close to my extension? London and Surrey


What is a Build Over Agreement?

Tel: 01483 666795         Email: info@drainage-surveys.co.uk

A Thames Build Over Agreement is a formal approval required when a property owner or developer plans to build within close proximity to or over a public sewer or drain managed by Thames Water. Thames Water is responsible for ensuring that public sewers are protected during construction work to avoid damage and ensure proper access for maintenance.

When building over or near these sewers, the risk of damaging the infrastructure or causing blockages is significant, which is why this agreement is necessary. It ensures that the construction work does not negatively impact the sewer, and that Thames Water can still maintain and access the sewer if needed.

Key Points of the Thames Build Over Agreement:

  • Survey and Documentation: Before starting the work, a CCTV drainage survey is often required to locate and assess the condition of the sewer. This helps in mapping the exact position and condition of the pipe in relation to the proposed construction.
  • Structural Design Considerations: The plans need to demonstrate that the building will not impose additional load on the sewer or obstruct its access.
  • Approval from Thames Water: A formal application must be submitted to Thames Water, including the survey results and plans for the proposed building. Only after Thames Water approves the build can the project proceed.

Why Use X-Rays Surveys Limited:

Using a company like X-Rays Surveys Limited for this work could be beneficial for the following reasons:

  1. Specialized CCTV Drainage Surveys: X-Rays Surveys Limited likely offers high-quality CCTV drainage surveys, which are a crucial part of the process. They help accurately pinpoint the location and condition of the drainage system relative to your construction site. These surveys ensure Thames Water gets the precise data needed for the agreement.

  2. Accurate Mapping: Their expertise in surveying can help you avoid unnecessary delays or risks during construction. Ensuring the precise position of the sewer relative to the building is essential to secure the agreement and avoid costly mistakes.

  3. Experience with Build Over Agreements: X-Rays Surveys Limited may have experience specifically with Thames Water’s Build Over Agreements. This means they understand the necessary requirements, regulations, and procedures involved, ensuring that the process moves smoothly.

  4. Comprehensive Reporting: They likely provide clear and comprehensive reports, which include video footage and detailed mapping, making it easier to submit your Build Over Agreement application with confidence.

By using a company like X-Rays Surveys Limited, you can minimize risks, reduce delays, and ensure that you meet all the legal and structural requirements for building near or over a Thames Water sewer.


The Below image is a mapped out drain in London, the client did not know that is was present at the rear of his property, this resulted in a complete redesign and new planning application. Paying out for a survey before you go full steam ahead with your plans is wise idea to prevent the above from happening and saving thousands of £££ on fees.



Tel: 01483 666795         Email: info@drainage-surveys.co.uk