A dry well is a type of hole in the ground designed to accept rainwater. If the dry well is designed properly, it can hold a volume of water for a while, and allow the water to slowly soak into the surrounding soil.
A dry well can be a simple system with a small capacity, or it can be an engineered system designed to handle large inflows of stormwater. Most residential systems are fairly simple, and don’t cost much to install. In this article, we’ll look at all the options.
It’s fairly common for a dry well to receive rainwater collected from roof gutters. If that’s the type of system you are thinking of installing, the bottom of the gutter downspout is connected to a solid (unperforated) 4-inch PVC drainpipe. Alternatively, the downspout can lead to a small plastic catch basin, and the water from the catch basin can lead to the dry well.
A dry well can also accept the discharge from a basement sump pump.
If you have a way to collect storm water that flows off of an impermeable surface on your property — for example, a driveway — you may want to direct that water to a dry well.
In some communities, it may even be legal (and desirable) to send water from your washing machine to a dry well. My advice: don’t hook up washing machine water to a dry well without first contacting your local code authority to see if this approach is legal in your jurisdiction.
Needless to say, you don’t want to locate your dry well near your foundation (since a dry well discharges water, and everyone wants a dry foundation). At a bare minimum, your dry well needs to be located 10 feet from your foundation. Farther is…