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Downspout Disconnection: An Effective, Easy-to-Implement, Inexpensive Way to Reduce Rooftop Runoff

Every river begins somewhere – its headwaters.

In urban and suburban areas, idyllic, forested headwater streams are often replaced by storm sewers or roadside ditches. Instead of rainfall being intercepted by the forest canopy and slowly infiltrated into the ground, it is gathered by gutters, downspouts and catch basins before being routed off the landscape as quickly as possible, stressing sewer systems and the natural creeks to which they drain. This system effectively short-circuits Mother Nature’s original stormwater control – the soil. Even poorly drained soils infiltrate water more effectively than pavement. And if the soil is vegetated, and that vegetation has well-developed roots? Even better.

One of the simplest ways to reduce runoff from residential property and to try to get our built environment to better mimic the natural environment is to re-direct rooftop runoff from storm sewers to lawn or landscape areas. This process is called downspout disconnection.

In its most basic form, downspout disconnection can be achieved by cutting the downspout above the ground surface and installing a splash block that directs the water to an adjacent grassed area. In some cases, it may be necessary to add an additional length of downspout or corrugated drain pipe in order transfer the water away from foundations or around other hardscapes, such as patios. Make sure to cover or plug the hole left in the ground where your downspout had entered your property’s storm sewer system. This basic downspout disconnection technique can also be enhanced by directing the downspout runoff into a rain garden or other landscape area that features native plants. Rain barrels can easily be added as well.

For most downspouts, the process should only take about 20-30 minutes and cost around $20 or less, making it one of the easiest, most cost-effective steps that homeowners can take to reduce rooftop runoff.

Furthermore, depending on the layout of your property and how you direct your now-disconnected downspout, Northeast Ohio Regional Sewer District customers may qualify for a Residential Stormwater Fee Credit.

Finally, before disconnecting your downspouts, please check with your municipality to make sure that you can legally disconnect and to check to see if they have any specific requirements related to disconnecting your downspout.

Here are some links to some helpful downspout disconnection tutorials and step-by-step instructions:

Washington, DC Department of the Environment Downspout Disconnection Guide (including step-by-step instructions)

Milwaukee Metropolitan Sewerage District Downspout Disconnection Instructions

How-To Video from Toronto

Blog Author: Jared Bartley, Rocky River Watershed Coordinator

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