Guides / Driveways · Updated
Permeable driveways
From the EPA's permeable pavement fact sheet, Vermont Sea Grant's driveway guide and the concrete paver industry.
Estimate for planning only, not professional advice. Check the manufacturer’s instructions, your local code and a licensed professional before you buy, build or install. Use at your own risk. Terms.
Short answer
A permeable driveway lets rain soak through into a stone bed underneath. It comes as porous asphalt, pervious concrete or permeable pavers, sits on several inches of open stone, and needs sweeping or vacuuming twice a year so it doesn't clog.
The three kinds
| Porous asphalt | 2 to 4 in thick; keep cars off 24 to 48 hours after paving (EPA) |
|---|---|
| Pervious concrete | 4 to 8 in thick (EPA); too much chloride deicer can make it ravel (UVM Sea Grant) |
| Permeable pavers (PICP) | About 3⅛ in thick for vehicles, on 1 to 2 in of bedding stone (EPA) |
What goes under it
A stone reservoir holds the water while it soaks in: typically 3 to 4 in of #57 stone under the bedding, and EPA says a deeper subbase may not be needed for a home driveway. Vermont Sea Grant's driveway guide goes deeper: 12 in of subbase on sandy, well-drained soil and 16 in otherwise for porous asphalt and concrete, 10 or 16 in for pavers. Its 16 in figure covers anything but sandy, well-drained soil.
Upkeep
Clogging is the main problem (EPA). Sweep or vacuum it twice a year, in spring after the snow and in fall (UVM). Never sand it for ice, and skip magnesium chloride on pavers (CMHA). Clean it when puddles cover more than a fifth of it.
Why bother
Long-term infiltration rates usually stay well above 1 in an hour (EPA). EPA also notes porous asphalt parking lots lasting more than 30 years, where regular asphalt in cold climates typically lasts 15.
Price and plan
Price pavers with the driveway cost calculator, count stone for the base with the gravel calculator, or catch the rest of the roof water with a rain garden.