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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.
Information needed before drainage installation
A drainage layout should be read with the site levels, external works, foundation details, utility routes, and the approved strategy. Conflicts are easier to resolve before trenches and concrete are in place.
- Existing and proposed levels
- Pipe sizes, falls, and invert levels
- Outfall and connection details
- Chamber schedules
- Foundation and service crossings
- Approvals and inspection requirements
Deep drainage and trench planning
Trench depth, ground conditions, nearby loads, groundwater, access, and pipe-laying sequence influence the excavation method and temporary support. The safe system of work must be designed for the actual site.
- Ground and groundwater conditions
- Trench support or battering
- Plant and lifting access
- Bedding and surround
- Backfill and compaction
- Testing before closure
SuDS and surface-water components
Sustainable drainage systems aim to manage surface water closer to where it falls. The selected components depend on the approved drainage design, infiltration evidence, available space, maintenance, and discharge restrictions.
- Permeable construction support
- Soakaways and infiltration features
- Attenuation tanks or crates
- Flow-control chambers
- Swales and filter features
- Safe exceedance routes
Testing, records, and maintainability
Before handover, drainage should be accessible for inspection and maintenance. Testing, surveys, as-built levels, photographs, and product information may form part of the required record.
- Air or water testing where specified
- CCTV survey where required
- As-built invert levels
- Connection records
- Maintenance access
- Commissioning and handover evidence