There are many examples of permeable pavements (or reservoir pavements) in mainland Europe and the US that still perform adequately after 20 years even though they have not been maintained.
All the evidence suggests that the pavements never fully clog and the loss in permeability reaches equilibrium, which is more than sufficient to deal with rainfall in the UK.
If the whole of a permeable pavement area becomes completely clogged it can usually be rehabilitated by sweeping it with a jet wash and suction machine.
Permeable pavements are like any other engineering structure – they require appropriate design, construction and maintenance.
STEVE WILSON (M), Stevewilson@epg-ltd.co.uk