Install Permeable Surfaces

In Los Angeles and other large cities, concrete and asphalt parking lots, driveways and sidewalks blanket much of the ground. These impermeable surfaces prevent rainwater from soaking into the ground, resulting in urban runoff.

Using permeable surfaces enables homes and businesses to capture rainwater for reuse or groundwater recharge (replenishing).

From impermeable to permeable

If you have impermeable paving that you would like to make permeable, there are two main methods for doing so:

  • Break up hard paved surfaces to create spaces for water to seep through
  • Remove and replace the surfaces with permeable paving

Either method allows water to soak into the soil, reducing runoff and increasing groundwater recharge. This practice also helps reduce the heat island effect (an increase in ambient temperature from heat-retaining buildings and paved surfaces). These methods will lower the surrounding temperature and reduce the need for air conditioning.

Note that before implementing these techniques, it is highly recommended to determine the soil permeability.

Breaking up a hard surface

There are a few options for breaking up a hard surface:

Create a broken concrete effect

  1. Check to make sure there are no underground utilities or water pipes under the area you are cutting. Contact www.digalert.org.
  2. Break up the concrete surface using a jackhammer or sledge hammer.
  3. Pull out concrete to leave a 2- to 3-inch space between the remaining pieces.
  4. Fill in the spaces with mulch or low-growing, drought tolerant ground cover.
  5. Recycle the leftover concrete.

Cut out areas in the concrete to plant trees, vines and shrubs

  1. Check to make sure there are no underground utilities or water pipes under the area you are cutting. Contact www.digalert.org.
  2. Mark the area you want to cut.
  3. Use a concrete cutter to remove the concrete.
  4. Remove the concrete and recycle the pieces.
  5. Break up the soil and add compost to increase soil health.
  6. Depending on the size of the space created and the location, plant a tree, dwarf fruit tree, non-invasive vine or garden.

Cut out a narrow strip down the center of a driveway

  1. Check to make sure there are no underground utilities or water pipes under the area you are cutting. Contact www.digalert.org.
  2. Mark the area you want to cut.
  3. Use a concrete cutter to remove the concrete.
  4. Remove the concrete and recycle the pieces.
  5. Fill in the spaces with gravel, mulch or low-growing, drought-tolerant ground cover.

Replacing a hard surface

There are a few options for replacing a hard surface:

Use mulch, gravel, ground cover or permeable pavers

  1. Make sure there are no underground utilities or water pipes under the area you are removing. Contact www.digalert.org.
  2. Break up and remove the concrete/asphalt surface using a jackhammer or sledgehammer.
  3. Pull out and recycle the concrete/asphalt.
  4. Fill in the space using one or more of:
    – 3 to 4-inch layer of mulch
    – Groundcover that can take foot traffic
    – Crushed rock or bark
    – Pavers or stepping stones

Use a permeable surface material substitute

Permeable surface material allows water to seep through. It is a good solution if the site is for driving (under 30 mph) or parking. Choose the type of permeable surface material that best suits your needs.

There are two basic categories. One looks and wears just like concrete or asphalt pavement, but doesn’t contain the fine particles that fill the spaces between the larger pieces of material in conventional pavement. The air spaces allow water to pass through the pavement and into a rock reservoir below, which filters it before it enters the surrounding soil.

The other group of materials includes various plastic or concrete grids and pavers. Products of this type allow grass or ground cover to grow in the gaps and are sturdy enough for cars.

For either type, you will need to remove the existing concrete or asphalt and then follow the instructions for your chosen pavement – or hire a professional to install it.

What can you do with leftover concrete?

Use the broken concrete to form raised planting beds for a garden. (Do not use asphalt in a garden. The petroleum in the asphalt could leach into the soil.)

Or recycle the concrete/asphalt. Note, some centers charge for this service. Ask if they will pick it up or if you need to deliver it to them. One center in the Northeast San Fernando Valley is:

Looney Bins, Inc.
(818) 768-7197
11616 Sheldon St.
Sun Valley, CA 91352

Resources for permeable pavement

Is this practice right for you?

Consult a professional if you're not sure. Also, see our web pages discussing maintenance issues, costs and other factors.