The direct answer
Start with the complete system, not one product or headline rate.
A plain-English guide to testing infiltration, interpreting variable Surrey ground and using results within a complete drainage design. A dependable plan connects the site evidence, approvals, access, installation sequence and finished reinstatement.
A test answers one part of the question
Infiltration results help estimate how quickly water can disperse. Siting, groundwater, catchment, available footprint and the route into the system still matter.
Representative position and depth matter
A shallow garden hole may not represent the layer around a proposed soakaway. Test locations should relate to the intended infiltration surface and site constraints.
Record conditions, not just one number
Soil layers, weather, groundwater observations, repeat results and recovery behaviour provide context for design and for deciding when another strategy is needed.
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