Roof Runoff + Downspout Connections

A residential downspout with water flowing into a depressed area of soil lined with rocks.

Metropolitan Water Reclamation District of Greater Chicago

Roofs make up a significant amount of impermeable surfaces in the city. Rainwater that falls on roofs has to go somewhere, and traditionally it has been directed into gutters and downspouts that are tied directly into the sewer system. All that water rushes right into the sewers—along with water from the streets and alleys as well as wastewater from toilets, sinks, bathtubs, dishwashers and laundry from homes and businesses.

One “green infrastructure” practice is to disconnect downspouts on buildings so that the water flows into cisterns, gardens or other landscape areas that can drink all that water up before it would hit the sewers.

Space to Grow schoolyards are designed with green infrastructure elements that capture rainwater and snowmelt right where it falls. Some schools capture the water that falls on their roofs and redirect it to the schoolyard gardens. This not only helps keep water out of the sewers, it also reduces the demand on using fresh water for the gardens and is a simple way to lower water usage, cut water costs and creates a healthier environment.

  • During the course of a year, approximately 29,000 gallons of rainwater will drain from a typical Chicago roof. This roof water alone can fill more than 360 bathtubs!

Do It Yourself!

All homes have gutters that direct water from the roof to different downspouts around the property. You can redirect the downspouts at your home so that the roof water runs over your lawn, into a garden or into a rain barrel. Here are some benefits to collecting water with rain barrels at your home!

  • Rain barrels collect rainwater you can reuse. Rainwater is free of chlorine, lime and calcium so you can use it to water your garden, wash your car or clean tools.
  • Rain barrels are easy to install and can help lower your water bills.

Two rain water barrels connected with a plastic hose.

Photo courtesy of Jamison.


  • The Chicago Metropolitan Water Reclamation District, has compiled a Green Neighbor Guide to prepare homeowners and landscapers for ways to manage stormwater.
  • Check out this video presented by the Metropolitan Water Reclamation District of Greater Chicago and Openlands on “How to Install a Rain Barrel” to see first hand how quick and easy they are to install.
  • Rain barrels typically are a solid, plastic barrel that is easy to paint. If you want to add art and color to your yard check out this video called “How to Paint a Rain Barrel” presented by Rutger’s NJ Agricultural Experiment Station.

Local Partners

  • The Metropolitan Water Reclamation District of Greater Chicago offers all Cook County residents rain barrels for under $50 and includes all the parts you need to install your rain barrel. You can also find rain barrels from the national hardware retailers such as Home Depot and Lowe’s.
  • The Center for Neighborhood Technology, RainReady Program has homeowner guidelines, factsheets and resources to prepare property owners and communities with best practices and information on how to reduce their risk of flooding.

Click here to download a PDF of this page in Spanish and English

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