What is a rain garden?

RG diagram

Rain gardens are designed to store and filter water that flows off of hard surfaces, like roofs and roads.

Most of the time, rain gardens look like a typical garden that just happens to deepen in the center. During heavy rainfall, the bowl-shape allows rain gardens to collect water and slow down the flow of water.

Both individual landowners and the greater community share in the benefits of rain gardens.

  • Rain gardens help protect the surrounding areas from flooding during heavy rainfall. Excess water is contained in the rain garden, instead of buildings, lawns, driveways, or parking lots.
  • Rain gardens reduce the strain on the stormwater system by catching runoff that would otherwise go straight into drains. This can help avoid expensive sewer system expansions, as well as reduce pollution entering streams and Puget Sound.
  • The sandy soil mix allows water to filter through easily. This process removes pollutants from water and helps to recharge groundwater.
  • Hardy, durable plants in the base of the rain garden uptake water and pollutants, and create habitat and food for wildlife and pollinators.
  • Rain gardens can require much less maintenance than lawns.
  • Less watering is required, as plants used in rain gardens are generally more drought tolerant than grass.



Evans OM2011 (2.5)Residential Rain GardenWakeman OM2013 (2)Crosspoint (2)