How to Dig a Dry Well

Digging a dry well presents several challenges, the most daunting one being the labor of digging. Adding a dry well, however, repays hard work by solving household drainage problems to avoid potential water damage for many years. Planning intelligently for a dry well can prevent both exterior and interior damage to your house. The concept of dry wells has existed for many years; new technologies contribute substantially to the success of this project.

Things You'll Need

• Shovel, earth auger or post-hole digger
• Burlap or plastic sheeting
• Wheelbarrow
• 10-12 feet of 3-inch PVC pipe (including elbow to connect to downspout)
• Gravel
• Large rocks
• Dry well shell, large trash can, 55-gallon drum, or large bucket
• Screwdriver or small saw
• Landscape fabric
• Sand

Instructions

Locating a dry well

1. Check downspouts on a day of heavy rain. Determine those taking the heaviest load of water from your gutters or producing the largest pools of water close to your foundation. Select one or more of these for placement of your dry wells. Your goal is to divert as much water as possible from your gutters to a point distant from your house.

2. Dig a test hole at least 4 feet deep at a distance of 10-12 feet from your foundation. Monitor the hole during several storms and during dry periods to determine the height of your water table and the drainage characteristics of your soil. In areas where the hole fills during dry periods, the height of the natural water table will make your dry well less effective than usual. If you find standing water days after a heavy storm, you need to plan a deeper hole and heavy layer of gravel under your well to improve drainage.

3. Choose a location that enhances the gravitational character of water drainage. By digging a dry well, you are creating an artificial means for water to flow downhill. Placing the dry well on a downward slope increases its effectiveness. Avoid areas next to a hill or bank that will drain into the dry well, leaving less room for the gutter water you need to divert.

Building the well

1. Dig a straight trench at least 12 inches deep at the base of your downspout, increasing the depth to 18 inches evenly over the course of 10-12 feet. Placing burlap or plastic sheeting next to where you are digging can make removing excess dirt easier than shoveling it out on the grass. Line the trench with a layer of gravel and lay your pipe.

2. Dig the hole for your well, at least 4 feet deep and wide enough to hold both your well container and a wrapping of landscape cloth. Make the hole deep enough to accommodate a bottom layer of gravel 6 to 12 inches deep, depending on how well your soil drains naturally, and an additional layer of gravel plus topsoil and turf on top of your container.

3. Create drainage holes in your container if you are using one with solid walls like a trash can with cover, plastic or metal drum or bucket. If you purchase a dry well shell, it will come with pre-cut holes. Holes should be 3-6 inches in diameter on the bottom of your container and 2-4 inches on the sides and top. If you are using a large uncovered bucket, turn it upside-down to provide a stable top surface or cover it with several layers of landscape cloth.

4. Punch an inlet hole for your PVC pipe and insert. At least 3-6 inches of pipe should extend into the container, and more is better than less.

5. Line your hole with landscape cloth, pressing it against the sides and bottom of the hole. Add your bottom layer of gravel and the container. Fill the container with large rocks, leaving as much space between them as possible and making certain rocks do not block the pipe.

Finishing up

1. Cover the top of your container with landscape cloth. Again, your goal is to prevent dirt from seeping into your well. Landscape cloth will let water through and keep dirt out.

2. Cover the container with an additional layer of gravel, and add a layer of several inches of sand. Sand should almost completely fill the hole to the top.

3. Shake turf to remove large clumps of soil clinging to grass roots. Leave a thin layer of topsoil on the roots, and re-lay the turf. Alternatively, spread a 1-2 inch layer of new topsoil and reseed grass.

Tips & Warnings

• If your yard is steeply sloped toward your house, you may need to consider a second dry well. In an area with a high water table, several small wells connected to several downspouts may be more effective than a single large one.

References

• More construction tips
• Water table considerations
• Dry well shell maintenance