Permeable interlocking concrete pavement (PICP) is comprised of a layer of concrete pavers separated by joints filled with small stones. Water enters joints between solid concrete pavers and flows through an "open-graded" base, i.e. crushed stone layers with no small or fine particles. The void spaces among the crushed stones store water and infiltrate it back into the soil subgrade.

The stones in the joints provide 100% surface permeability and the base filters stormwater and reduces pollutants.


Why Use Permeable Pavers?

Federal, state, and local sustainable site regulations aim to reduce environmental impacts of increased runoff from roofs and pavements. Past practices for controlling stormwater have included detention ponds for collecting runoff and slowly releasing it into a lake, stream, or storm sewer system. More recent approaches target infiltrating runoff at the site.

PICP for patios, walkways, driveways, and housing development roads infiltrates stormwater, reducing or eliminating detention pond requirements. Storm sewer pipes and inlets also can be reduced or eliminated. PICP reduces runoff and pollutants, recharges groundwater, and helps reduce downstream erosion and flooding.