What is an Impervious Surface?

Posted On: February 02, 2021

Roads. Parking lots. Sports fields. Patios. Rooftops. Sidewalks.

These surfaces are all around us and are generally considered useful constructs in everyday life. But they also pose serious environmental hazards.

Known as impervious surfaces, these areas may slow or prevent water from soaking into the ground. As a result, more water is forced to run off the land.

Why Are Impervious Surfaces a Problem?

When rainwater can’t soak into the ground, it collects above ground and then rushes into storm drains. This creates threats to the quality and even quantity of water in urbanized areas where impervious surfaces are abundant.

The primary concern is flooding. Impervious surfaces cause irregular runoff, which can erode and change the structure of existing streams. Since water flows more quickly off these surfaces, flooding becomes a more regular and more intense occurrence downstream.

Impervious surfaces also threaten water quality. Any substance that falls on these surfaces – such as engine oil on a parking lot, animal waste on a sidewalk, or pesticides on a sports field – can be washed away during heavy rain into the closest storm drain and directly to natural water sources used by both humans and wildlife. This is a serious pollution concern.

What Can You Do?

Those in urban areas can help reduce the impact of impervious surfaces by minimizing their footprint at home and work. This can be done by using alternative materials (such as mulch, gravel, uncemented brick or grass pavers), green scaping rooftops with planting, and reducing the square footage of structures like decks, patios and parking lots on your property. Steps like these can help control flash flooding and pollution in our waterways.

If you have concerns about impervious surfaces creating unsafe conditions around your home or business, don’t hesitate to call the professionals at iSTORMWATER. We offer both preventative stormwater maintenance and flooding mitigation services that can save you money and possible property damage. We offer a free consultation, so contact us today!


For stormwater management services in Maryland, Northern Virginia, or Washington, DC, call iSTORMWATER at (443) 699-2828! ​


Real Results

iStormwater LLC was an excellent choice. They made the process of the Storm water pond repairs seamless. They took charge of the project and got the project approved and passing the inspection. We highly recommend them and would use them again.

Lyonswood HOA

Incredible stormwater management service. The owner John consulted on a property I manage and ended up saving us thousands of dollars in environmental fees from the government. Now, our property is compliant with the EPA and we have a great partner to keep us maintained on storm water regulations over time.

Kelly E.
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