The roof at Raleigh Union Station with green plants and soil that clean and absorb rain

This green roof at Raleigh Union Station collects rain before it falls to the ground or evaporates into the air. This type of planted roof helps reduce pollution to a stream called Rocky Branch.

Green Roofs

What you need to know

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How it works Best Location Benefits

How it works

A regular roof sends stormwater right to storm drains and streams. In contrast, plants on a green roof slow down rain when it reaches the roof. When this happens, the water absorbs into the soil or evaporates into the air.

The roots of the plants also keep the soil in place as it removes pollution from the water. Together, plants and soil reduce how much stormwater runoff reaches the ground, storm drains, and creeks. 

Best Location

  • Sunny, horizontal spaces with a small slope 
  • On a building that can support the weight of a green roof


  • Reduces the amount of pollution that reaches streams 
  • Lowers heating and cooling costs 
  • Provides wildlife habitat 
  • Improves air quality 
  • A good community space or outdoor amenity