How to Install a Dry Well
Diverting roof runoff properly makes for a less slippery yard and walkway
Q: We have a downspout that dumps rainwater onto our front walkway, which in winter turns into a sheet of ice. Is there a way to fix this problem? —Tabby McCarthy, Olanthe, Kansas
Roger Cook replies: A wet walkway is not only a slipping hazard, it contributes to damaging frost heaves that can break apart pavement. If you can't relocate the downspout, route the water under your walk and out to a dry well buried in your lawn. This perforated, open-bottom plastic barrel, which sits in a hole and is surrounded by stones, captures water coming off your roof, and lets it slowly disperse into the ground. Your walkway will be drier, and your storm drains will be less overloaded.
To determine how many dry wells you'll need, enter your roof area and soil type into the calculator at NDS, Inc. When you're ready to start digging, follow the steps on the next page. After you're done, fit your gutters with leaf guards so that the dry well won't fill up with debris.
Shown: washed, rounded stones ensure that a dry well will disperse roof runoff properly into the ground.
Dig the Hole and Trench
Coming out from the downspout, at least 10 feet from the foundation (and 3 feet from any property line), dig a hole about 4 feet deep and wide. With a long-handled shovel, tunnel under the sidewalk and dig a trench 1 foot deep and 6 inches wide that slopes gradually toward the hole. Shovel the soil onto a tarp. Save the sod to patch over the hole.