How to Build a Simple Dry Well
Ask This Old House mason Mark McCullough installs a dry well for a homeowner with drainage issues in his backyard
- Before starting the project, call the local utility locating service and have them mark out any potential underground utilities that could get in the way of the dry well.
- Lay out the PVC pipe and determine the location for the dry well. The solid pipe will go closest to the house, and the perforated pipe will go closest to the dry well.
- Use the shovel to cut into the soil just underneath the grass and move the top layer to a tarp. That way, the grass can be put back in place once the trench is dug.
- Next, dig a trench to accommodate the PVC pipe that’s roughly 8-10 inch deep. As the trench gets closer to the dry well, make the trench slightly deeper and slightly wider to ensure no water leeches back towards the house.
- Now start digging the hole for the dry well. It should be about 4 foot in diameter and 3 foot deep.
- Cover the bottom of the dry well with a few layers of landscape fabric until the hole is completely covered.
- Use the remaining landscape fabric to line the trench. It only needs to go as far as the perforated pipe.
- Pour the crushed stone into the hole one wheelbarrow-full at a time. Between each pour, tamp down the crushed stone with a hand tamper. Repeat this process until the hole is filled to the level of the trench.
- Put a thin layer of crushed stone in the trench.
- Connect the PVC pipes using the couplings and the PVC glue. Use the elbow to connect a vertical piece to catch the rainwater from the gutter. Once it dries, place the pipe in the trench.
- Fill the rest of the trench and the hole with the remaining crushed stone, leaving just enough room at the top for the layer of grass.
- Fold over the landscape fabric to cover the crushed stone.
- Backfill the hole and the trench with the grass.
Installing a simple dry well requires few tools and materials. Mark lined the trench with landscape fabric, which can be found at any home center. He then filled the trench and the hole with crushed stone, which can be found at masonry supply stores and some home centers. The pipe he installed was two sections of solid PVC pipe and one section of 4 inch perforated PVC pipe. The pipe and the PVC glue required to secure the connections, are found at home centers.
When installing a dry well in a small yard with little space for leeching, Mark also suggests installing a plastic basin in the hole to allow for more controlled drainage. The yard in the video was massive and slightly sloped downhill away from the house, so the plastic basin wasn’t necessary.