Map surface water, permeable backfill, filter separation, subsoil collection, outlets and the final discharge route. Do not assume an exposed pipe proves the system is complete or functioning.
Trace the water
- Surface flow arriving from above or adjoining areas.
- Ponding and infiltration immediately behind the wall.
- Drainage aggregate and filter separation around collected water.
- Pipe grade, continuity, maintenance access and outlets.
- The final stormwater or approved discharge destination.
Visible clues
Persistent dampness, staining, soil loss, clogged outlets, water emerging through joints, erosion at the toe and movement after rain can be useful evidence. They do not identify the complete cause without site investigation.
What a drainage quote should show
Ask for aggregate type and extent, geotextile or filter details, pipe type and route, clean-outs or maintenance provisions, outlet locations, connections, surface falls and reinstatement. The wall quote should distinguish these from broader site stormwater work.
Confirm the lawful property-specific discharge path with the relevant authority and professionals. Do not redirect water across boundaries or into an unsuitable location.