Why are permeable sidewalks (sidewalks that allow water to drain through them) a sustainable option?

With normal sidewalks, water washes off all of the chemicals that lie around on our roads and sidewalks. Then all this dirty water goes back into the water system. If the sidewalk is permeable, water filters through it dispersing the chemicals in a way the environment can cope with them and returning, clean, to the water system.

Our sidewalks collect air pollution that was taken out of the skies by rain, rubber and other materials that make the soles of our shoes (ever wondered where the soles of your shoes go when the wear away?), they collect gasoline from cars and they collect loads of other nasty stuff.

Permeable sidewalks help to preserve water, our #1 most important and crucial resource. Without it we would never have come about, and without it we are in serious trouble.