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Permeable Pavement

Permeable pavement is built with materials that let water pass through. Replacement of traditional concrete or asphalt driveways with permeable pavement allows rainwater to naturally filter through the ground and reduces stormwater runoff.  Permeable pavement provides a strong, solid surface that can be installed on driveways, walkways, and patios and can also serve as attractive landscaping features, raising property values.

Image of Permeable Pavement

 

There are three main forms of permeable pavement. In addition to these forms, listed below, there are grass pavement systems and gravel-based pavement systems. Others could be submitted for consideration on a case-by-case basis.

  • Permeable interlocking concrete pavement (PICP)
  • Pervious concrete (PC)
  • Porous asphalt

 

 

Why Should I Install Permeable Pavement?

Patios, sidewalks, and driveways are hard surfaces that prevent water from soaking into the ground. Various changes, or retrofits, can be applied to these hard surfaces to help prevent stormwater runoff and pollutants from entering our streams. An effective retrofit to reduce runoff from residential properties is the installation of permeable interlocking pavers.

Permeable pavements:

  • increase on-site infiltration and reduce runoff

  • are easy to install

  • can be an effective alternative to traditional walkways and driveways

Permeable pavements address important environmental issues and support sustainable living. They not only have a positive environmental impact, but can also be economical and function well with little maintenance.

 

 

Is Permeable Pavement Right for Me?

Image of the front of the RainScapes Permeable Pavement Guide
Want Help with Assessing Your Property and Designing Permeable Pavement?  
Download the Guide (PDF, 382KB)

Permeable Pavement is pavement that will reduce runoff and still allow you to have a hard surface.

  • Permeable pavement is a good option if there are large amounts of hard surfaces (concrete, asphalt)

  • This is typically more expensive than other RainScapes techniques

  • This requires proper installation by a certified contractor

  • This requires annual maintenance with sweeping and/or gravel replacement

  • Pavers enhance curbside appeal and increase property value

Installing permeable pavement on your property reduces the stormwater contribution to our streams from driveways, walkways, and patios. You will play a positive role in preserving the environment and water resources. 

If you are interested in installing permeable pavement on your property (and receiving RainScapes Rewards Rebates), contact a certified contractor to make an assessment of your property. Permeable Pavement may not be suitable for your property and is not recommended as a do-it-yourself projects. A contractor will be able to properly assess your property and explain installation and maintenance issues. At this time, we do not generally provide rebates for permeable pavements except for the first two (PICP and PC).

 

How to Assess Your Property

Follow these basic steps to assess your property and determine the best location for a permeable interlocking paver project:

  1. Locate your property’s hard surfaces. Are there large areas of driveways or patios where you would like to improve either rainwater infiltration or visual appeal? The pavement area should be slightly sloped away from your buildling foundation.

  2. If you choose to install permeable pavers, determine if there is adequate space for them to meet the minimum RainScapes Rewards Rebates eligible project size. The minimum project size to receive a rebate for residential properties is 100 square feet of existing hard surface that will be converted to permeable pavers. For commercial properties the minimum size is 300 sq. feet.

  3. Assess your current landscaping features and choose products that will enhance the overall character of your property. Permeable interlocking pavers can be decorative as well as functional.

  4. Choose a location where the practice best meets your budget. Larger applications will result in a higher cost. Smaller-scale projects may be more practical if you are on a budget.

  5. You do not want to use pavers in areas that accumulate a lot of sediment and debris. They can clog and not let the water infiltrate.

 

Image of a permeable pavementInstalling Your Permeable Pavement

It is recommended that you work with a certified contractor to install your permeable pavement. To be eligible for a rebate, a PICP certified contractor must be used for installation. You can ask the RainScapes team for help in locating a certified contractor. 

The RainScapes Permeable Pavement Guide (below) has suggestions and useful information on the best questions to ask your contractor and tips for installing the pavement, cost and maintenance. 

The RainScapes program has knowledgeable and helpful staff who can help you through the process as well as the RainScapes Rewards Rebates program with great financial incentives for installing permeable pavement.  

 

Download the RainScapes Permeable Pavement Guide (PDF, 382KB)

 

Maintaining Permeable Pavement

As the property owner, you are responsible for all maintenance of your permeable pavement unless a shared maintenance agreement has been made with the DEP Stormwater Facility Maintenance Program. The pavement requires regular maintenance in order to continue filtering rainwater, including:

  • Removing leaves and tree debris

  • Sweeping

 

Actions You Can Take to Maintain Your Permeable Pavement

Seasonal Actions

As Needed Actions

✔ Inspect your porous pavement after storms to make sure that rainwater properly drains through the material.

✔ For commercial parking lots, use a vacuum sweeper to remove sediment and debris.

✔ Pressure wash as needed to alleviate clogs in the pavement. Be sure to remove any washed out sediment.

✔ Remove leaves from surfaces during the fall.

✔ Inform contractors working on your property of the location of porous pavement areas to prevent damage. We recommend adding a sign that identifies the surface as porous.

✔  Remove snow with a rubber tipped shovel/plow or keep plow tip 1 inch above the surface. The remaining snow will melt and drain through the surface.

✔ For permeable interlocking pavers, replace/ replenish the top layer of stone between joints with new clean stone after sweeping, vacuuming, or power washing.

 

 

 

Actions You Shouldn't Take to Maintain Your Permeable Pavement

Don't...

✘  Don't stockpile mulch, sand, salt, soil, or yard waste on porous pavement.

✘  Don't pile snow that contains sand or salt on your porous pavement.

✘  Don't replace vehicle fluids over porous pavement.

✘  Don't apply sealants over porous pavement or repave the area with materials that do not let water pass through.

✘  Don’t let large vehicles regularly drive on or turnaround on porous surfaces.

✘  Don’t apply sand for winter snow removal on porous pavement or on adjacent areas, such as sidewalks, that may drain onto the porous pavement.

✘ Don't disturb soil uphill from the pavement without installing a silt fence.

 

DEP can answer your questions and provide additional guidance about maintaining your permeable pavement. Please email askdep@montgomerycountymd.gov call the Montgomery County Customer Service Center at 3-1-1.

 

Image of the front of the Permeable/Porous Pavement Maintenance Fact Sheet.
Want Help with Maintenance, Troubleshooting and Timelines?  
Download the Fact Sheet
(PDF, 379KB)

Permeable Pavement in the Stormwater Facilities Maintenance Program

The Stormwater Facilities Maintenance Program is responsible for maintaining all public stormwater facilities as well as all private facilities that transferred their maintenance to the County.  

Not sure if your permeable pavement is part of the Stormwater Facilities Maintenance Program.  Check out online Facilities Map or email askdep@montgomerycountymd.gov.

 

Can I remove my permeable pavement after installation?

No, you cannot remove any facilities that were part of your building installation - these are permitted structures and DEP maintains a database of these facility locations as part of the Stormwater Facility Maintenance Program. DEP may perform a maintenance inspection of your practice if it is a permitted structure.  Property owners must contact DEP before any major changes can be performed to the structure. 

 

 

 

 

Rebates, Resources and Financial Incentives

Interested in installing permeable pavement?  The County offers incentives to help make the decision a little easier.

 

Logo of the RainScapes programThe RainScapes Rewards Rebates Program

The County offers technical and financial assistance (in the form of rebates) to encourage property owners to implement RainScapes Rewards Rebates techniques on their property, including permeable pavement.

  • Residential properties are eligible for up to a $2,500 rebate

  • Commercial, multi-family or institutional properties are eligible for up to a $10,000 rebates.

To receive a rebate for permeable pavement for residential properties, you must hire a certified contractor and convert a minimum of 100 square feet of hard surface to a permeable interlocking paver surface. To receive rebates for commercial, multi-family, and institutional properties, a minimum of 300 square feet of hard surface area must be converted to permeable interlocking pavers. The amount rebated will be based on the area of impervious area treated, on a square footage basis. 

To participate in the RainScapes program, your property must be located in Montgomery County, outside of the municipal limits of the City of Rockville, City of Takoma Park, or City of Gaithersburg. Projects are not eligible if they are associated with permit approval requirements for new building construction, additions, or renovations.

​The program is funded each fiscal year (The FY begins July 1 and ends June 30). Annual funds for the programs are limited, so rebates will be awarded on a first-come-first-served basis.

The RainScapes program also provides technical assistance to help with permeable pavement installation. They have a wealth of information, expertise and want to help!

Learn more on the RainScape Rewards Rebates webpage.

 

Image of a permeable pavement walkway.

 

 

The Water Quality Protection Charge Credit Program

After you have installed your permeable pavement, you are now eligible to receive a credit off your annual Water Quality Protection Charge (found on your yearly property tax bill).  The credit provides an incentive for maintaining your permeable pavement and other stormwater management practices.  

You must apply for the WQPC credit separately – the credit will not be provided to you automatically.

Residential property owners can receive up to 50% off their WQPC depending on the type and size of stormwater management practices on the property. 

Non-residential and multi-family properties can receive up to 50-60% off their WQPC depending on the type and size of the stormwater management practices on the property. 

Learn more on the WQPC Credit webpage.