A dry well is a much-needed addition to your back yard if you suffer drainage issues during rainstorms. The following steps will show you how to build your own drainage dry well. Keep in mind that this sort of project normally is not a do-it-yourself project. As a result, you may wish to build a dry well only after consulting with a professional.
Find A Suitable Area
The purpose of a dry well is to direct water away from your house (and therefore its foundation) to an area where the ground can absorb the water. For this reason, you need to identify a proper location in your back yard. An area located on a slight slope is preferable, but only as long as it is not close to the foundation of the house.
Dig the Trench
Once you have selected the area for the dry well, you can start digging the channel to it. First, locate the downspout attached to your house. The downspout is where all the water from the roof runoff and gutters comes through. Next dig a trench that is 12 inches deep and 6 inches wide from the downspout to the location of the dry well.
You will need to modify your downspout slightly so it reaches the trench. Use a combination of hacksaw and fittings/adapters to get the downspout where it needs to be.
Lay the Pipe
Measure the length of the trench to where the dry well will be and cut the pipe to suit. Attach the solid pipe to the downspout and line the trench with it. Finish with a perforated pipe.
Cover the pipe with the dirt you removed from the trench but leave the perforated pipe uncovered. Tamp down the soil to pack it around the pipe.
Place drainage stones around the end of the trench. Install the overflow valve according to the manufacturer's instructions. Wrap the perforated pipe with the landscaper's fabric, then cover it with drainage stones. Add more dirt around the area and tamp it down.
Create the Dry Well Reservoir
You can now make the actual dry well. Use the tape measure to determine how large you want your dry well to be. Stake out the length and the width of the proposed dry well. Tie string between the posts to clearly mark it.
Use the spade to break up the ground along the perimeter of the stakes you placed. Excavate the entire interior with your shovel. Dig down about 1 1/2 feet and check the level of the reservoir. Remove more dirt, if necessary, and make sure the reservoir is positioned so that the pipe is centered. Tamp the dirt flat.
Fill the area with four inches of drainage stones. Even the stones out in one layer.