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Roadside Guide to Clean Water: Porous and Permeable Paving Materials

These pervious surfaces are designed to allow snowmelt and rain to drain through the hard, but porous, top surface.

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Updated:

April 29, 2025

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Photo by Scott Sjolander

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Porous and Permeable Paving Materials at a Glance

Porous pavement and permeable pavers are types of paving materials intended to minimize flooding and stormwater runoff while armoring the land surface so it can carry the weight of foot or vehicle traffic. These pervious surfaces are designed to allow snowmelt and rain to drain through the hard, but porous, top surface. Traditional paving surfaces are considered impervious because rain and melting snow cannot pass through into the soils. Examples of porous and permeable paving materials include specially designed concrete, asphalt, and paving stones. To work properly, they must be installed over a carefully prepared subsurface. That might simply be graded washed stone, but it is likely to also include piping, storage tanks, and basins. Porous and permeable paving materials are more widely used in modern urban spaces and on commercial or industrial properties.

How Porous and Permeable Paving Materials Work

Permeable pavers and porous pavement help reduce stormwater runoff and prevent flooding. These engineered paving materials have large pore spaces that allow rainfall to pass through and be moved away from the site. This minimizes puddles, ice, and standing water directly on the surface. It also means less water is flowing off the surface and causing flooding downhill. The modified surface under the pavement can store water until it either absorbs into the soil below or is directed through pipes to a basin or other outlet. Pervious pavements must be maintained to keep them working properly. This includes regular cleaning to prevent clogging, often done through vacuuming.