Sustainable Urban Design: Educator’s Toolkit for Project-Based Learning, page 15 of 20

Students disconnect a downspout and divert water to a rain garden
LEAF students disconnect a downspout and redirect water to a rain garden. © The Nature Conservancy

Green Stormwater Infrastructure: Downspout Disconnection

Disconnecting or redirecting one or more downspouts on a building is a simple way to make a green difference. Typically, a downspout directs storm water toward a sewage drain—in many urban environments, the downspout goes directly into the ground, where it moves the water to the sewage system. In some cases, the downspout is open at the base of the building and water flows over impervious surface on its way to the sewer, unable to be absorbed into the ground and picking up pollutants on its way. In either case, water from downspouts can be redirected to permeable ground. This not only insures that the water enters the natural groundwater filtration system, but also reduces the demand on the municipal sewage system.

Note that downspout disconnection can be part of a larger stormwater plan that might include installing a rain garden and/or harvesting rainwater. Consider working with students to build a rain garden in a box, also called a Grattix, or a stormwater planter and position it under a downspout. Students can even experiment to see if they can improve upon the design!

Get Started

  1. Check with your government officials about regulations and guidelines regarding downspout disconnection (many municipalities have guidelines available online). Ask if they have personnel who can advise on specific projects.
  2. Identify the building(s) for which you want to disconnect the downspouts and locate the downspouts. You might want to have students sketch the buildings, downspouts, and surrounding permeable surfaces.
  3. Follow the process laid out in your local regulations, if available, or in one of the following resources:
  4. Decide whether you want to do any planting or make other changes (e.g., add gravel or other elements) to the area where the water is now being discharged.
  5. Set up a schedule to check on the new arrangement, particularly after significant rainfall.
  6. Invite any local or school officials you've worked with along the way to view your handiwork!

Common Challenges

  • Getting permission from maintenance staff and school administration. Have the local regulations and other supporting information in hand when you present your ideas.

Maintenance Schedule and Other Notes

  • Any downspout needs to be checked periodically to make sure it's not blocked with debris and that the water is running freely.
  • Check after the first rains and occasionally thereafter to make sure the area where the water has been redirected can handle the amount of water it is receiving. Is the water pooling up or running off the surface? If so, the area might need gravel added, additional planting, or other modification.

Related Lessons and Classroom Integration

Additional Project Resources