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When we build or introduce new surfaces to an existing landscape, it’s important to consider the natural flow of water in that area may be disrupted. Adding impervious surfaces like roofs and residential driveways increases the amount of stormwater runoff, which collects particles of oil, dust, and other pollutants as it travels over the surface of the ground.

This results in an excess of stormwater runoff, which left untreated will travel through drains and gutters until finally depositing into lakes, streams, and the ocean. Negative consequences of this include the following:

• Pollutants are carried into the oceans and our waterways where they can affect wildlife and water quality
• Debris carried in stormwater can clog our storm drains and cause residential flooding
• Increased volumes of stormwater can erode streambanks and hillsides
• Contaminated water can lead to beach and lake closures