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Use this at the planning stage.
This guide helps you prepare questions and information. Project designs, ground conditions and any required approvals need to be confirmed by the relevant professionals.
Find out what is already there
Collect available drainage drawings, records and any inspection or survey information. Identify which parts of the system are known and which remain uncertain. If the proposed building is close to a drain or sewer, ask the designer to establish what further information and coordination are needed. A line on an old drawing should not be treated as a complete condition report.
Connect the proposed layout to the levels
The building layout, finished levels and drainage routes need to work together. Share proposed kitchen, bathroom and other connection positions with the drainage designer, along with any intended external works. Confirm the current design before pricing or installing routes. A late change to a connection point can affect work beyond the individual pipe.
Think about access after completion
Consider where inspection points and maintenance access will sit once the extension, paving or landscaping is complete. Record who is reviewing the drainage arrangement and who is responsible for required consents or agreements. Approved Document H is an authoritative starting point for drainage requirements in England; it is not a substitute for a site-specific design.
- Existing records and any drainage survey results
- Proposed foul and surface water arrangements
- Relevant levels and connection details
- Maintenance access and outstanding design questions
Prepare the construction enquiry
Send LG the current drainage layout alongside the building drawings and site details. State whether the request is for a drainage stage or a larger groundworks package. If a survey, design or approval is still being arranged, say so. Clear information lets the team distinguish the specified installation from provisional work and unresolved interfaces.