How to Construct a Dry Well

A properly constructed dry well blends into the lawn.

A dry well is a gravel-filled hole that aids in the storage of runoff from roofs or other solid surfaces until the surrounding ground can absorb the water. Dry wells are located at least 10 feet away from buildings and any landscape features such as pools to reduce the risk of water damaging the foundation of the structure. Before constructing a dry well, plan the location and contact your utilities to prevent rupturing gas, electric, cable, water or sewer lines during excavation.

Things You'll Need

• Tape measure
• Landscaping paint
• Shovel
• Axe or hatchet
• Heavy garden rake
• Landscaping fabric
• Rebar
• Hacksaw
• 12-inch perforated pipe
• Drill
• ¼-inch drill bit
• Drain for overflow
• Small plastic bags
• Wire or zip ties
• 1 1/2- to 3-inch crushed stone
• Hand tamper

Instructions

1. Lay out the area planned for the dry well with a tape measure and landscaping paint. For example, if the dry well is planned to be a 4-foot-by-4-foot square, measure the area and draw the outline on the ground with landscaping paint.

2. Dig along the lines to the planned depth of the dry well. Keep the walls as straight as possible. Cut through roots with an axe or hatchet. Smooth the bottom with a heavy garden rake.

3. Line the bottoms and sides of the pit with landscpaing fabric. Secure the fabric at the top of the wall with landscaping fabric stakes. The fabric stakes look like a bent piece of wire.

4. Measure the width and length of the pit. Measure and mark a piece of rebar for each direction. Cut the rebar with a hacksaw. Lay the two pieces of rebar on top of each other to create an “X” in the bottom of the dry well.

5. Measure the depth of the dry well. Cut a piece of perforated pipe with a hacksaw the same length as the depth of the well. Drill four evenly spaced opposing holes 2 inches from one end of the pipe with a ¼-inch drill bit.

6. Connect the overflow drain to the opposite end of the perforated pipe. Cover the end with a small plastic bag.

7. Place the perforated pipe in the dry well vertically, centered over the centers of the pieces of rebar. Insert wire or zip ties through the holes in the bottom of the perforated pipe and then around the rebar to secure the perforated pipe to the rebar.

8. Fill the hole to within 3 feet of the soil line with 1 ½ to 3-inch crushed stone. If placing a lateral drain line in the dry well, cut the perforated pipe to the appropriate length and place on top of the stone. Continue filling with crushed stone until the top of the gravel is 12 inches lower than the soil line.

9. Fill the top 12 inches with soil, cover with sod, tamp the sod into place and water well to establish the sod.

10. Remove the plastic bag from the overflow drain.

Tips & Warnings

• If gutters and downspouts will be drained into the dry well, install a screened fitting at the bottom of the downspout before it enters the dry well. This will help to reduce debris from blocking the perforated pipe in the dry well.

References

• Bagley College of Engineering: Mississippi State University: Dry Well
• Treddyffrin Township: Dry Well