Roll out the (rain) barrel!

Traditionally, roof runoff in Chicago has been routed via downspouts directly into the sewer system. However, the City of Chicago encourages the careful disconnection of downspouts so that roof runoff can flow directly into vegetated areas. There are several options for doing this:

1. Runoff can be sheeted across the lawn.

2. Runoff can be routed via a surface swale into a rain garden or onsite detention or retention facility (see separate discussions of these approaches).

3. Runoff can be temporarily stored in rain barrels or cisterns.

Rain barrels can effectively capture and store the runoff from small to moderate storms. The stored water then can be used to irrigate lawns and landscaped areas in between storm events.

Rain Barrell

The effectiveness of rain barrels (or cisterns) is a function of their storage volume in comparison to the size of the roof. In a simple residential example, a 1,200 square foot roof could utilize 55-gallon barrels to store runoff from downspouts at the four corners of the house. The resultant storage is equivalent to about 0.3 inches of runoff. While this volume will not substantially reduce flooding from large storms, it can considerably reduce direct runoff from smaller storms and divert water from the combined sewer system. The actual effectiveness of this approach will depend on the regular draining of rain barrels (such as for irrigation) between storm events. In that respect, rain barrels are most effective when used during the growing season.


Effective downspout disconnection requires that there be adequate landscaping or vegetation available to accept the water. Rain barrels are appropriate where vegetation is limited, provided that the collected water can overflow to open green space areas. Diversion and/or storage of roof runoff with rain barrels or cisterns is applicable to most residential, commercial and institutional properties in the City.

Maintenance Considerations

Occasional cleaning may be necessary to remove debris, such as leaves, coming off the rooftop. A mesh filter can be inserted at the top of a rain barrel. The barrel must be sealed during the warm months of the year to avoid mosquito breeding. To avoid freezing, the rain barrel should be drained prior to winter.

Cost Considerations

Typical costs for a ready-made rain barrel range from $20 to $150.Homeowners can reduce costs by making their own.

Local Examples

Much of the rain that falls on Chicago Center for Green Technology’s roof flows into four 3,000-gallon cisterns and is later used to water the landscape.

Prices for Metropolitan Water Reclamation District of Greater Chicago (MWRD) rain barrels have been deeply discounted.

The MWRD Board of Commissioners recently approved subsidies for Cook County residents. At $21.96 each, there is a limit of two. For residents age 65+, the price is $10.98 per barrel, also limit two. There are no delivery charges.

“We are happy to continue this popular program at discounted rates to ensure we are collecting as much water as possible during heavy rains,” said MWRD President Kari K. Steele. “Please consider installing a rain barrel and help us manage stormwater and protect our water environment.”

Rain Barrel
MWRD rain barrels hold up to 55 gallons, stand 36 inches tall and 24 inches wide, and come in four colors with overflow valves and spigots.


Now in its 15th year, the MWRD rain barrel program promotes water conservation and green infrastructure to capture rainwater from roofs and save it for later use. The rain barrels provide a variety of benefits, including:

  • Disconnecting downspouts and hooking up rain barrels can help reduce basement backups and flooding by decreasing the amount of water overwhelming the sewer system during heavy rains.
  • Rain barrels and similar forms of green infrastructure can also improve area water quality by reducing the amount of urban runoff entering area waterways or inundating the MWRD’s seven water reclamation plants.
  • Rain barrels can save homeowners on their water bills and conserve filtered, treated drinking water for other purposes.
  • The water can be used to water lawns, plants and gardens and wash cars, work boots and tools.
  • By refreshing lawns and gardens with the reused water, rain barrel users can help recharge underground aquifers during dry spells.

Since 2014, the MWRD has distributed nearly 137,000 rain barrels to homeowners, businesses and community organizations partnering with the MWRD to protect their water environment. MWRD rain barrel demand increased in 2020. As more homeowners were trapped in quarantine, they spent more time in their gardens and improving outdoor spaces.

“We all know how we should recycle plastics, glass, and paper, etc., but water must be recycled too,” said MWRD Commissioner Josina Morita. “Rain barrels are a valuable form of green infrastructure, and the more opportunities we have to collect rainwater, the better are our chances of relieving our sewers and infrastructure and protecting our homes from basement backups and our communities from flooding.”

The recycled MWRD rain barrels include a leaf and mosquito filter screen, spigot, overflow adaptor and overflow hose. The rain barrels come in four colors: black, blue, terra cotta and gray.

For installation instructions, watch the MWRD’s video. To learn about other green infrastructure practices to be incorporated at home, read the MWRD’s Green Neighbor Guide. For more information, call (312) 751-6633, visit, or email [email protected].

Once installed, the MWRD encourages rain barrel users to contact the MWRD or tag the MWRD with a picture and post on social media on Facebook, Instagram, LinkedIn, and Twitter using #MWRDRainBarrel.


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