Residential Dry Well Design

The basic design parameters for a dry well are its storage volume and the permeability rate of the subgrade soils.

Residential dry well design. Lay out the pvc pipe and determine the location for the dry well. A dry well must have sufficient storage volume to contain the design runoff volume without overflow while the subgrade soils permeability rate must be sufficient to drain the stored runoff within 72 hours. A dry well or drywell is an underground structure that disposes of unwanted water most commonly surface runoff and stormwater and in some cases greywater. Each dry well tank holds up to 50 gallons of detention volume per unit.

Modular units can be connected in a series or stacked to meet a variety of project needs. The bottom of the dry well should be 2 feet above the seasonally high water table or bedrock. You typically want to install your dry well near the downspout that has the biggest issue with water pooling up around it. Dry wells are designed to keep water from building up near your home when it rains.

Residential drainage systems often feature outdoor catch basins and or dry wells so a solid understanding of what they are and the jobs they do can be beneficial. Lay out lengths of 4 inch diameter pvc pipe from the end of the downspout out to the dry well location. The top of a dry well should have approximately 1 foot of cover. Dry wells should empty within 72 hours of a rain event.

Drywell is an underground perforated pipe surrounded with gravel that collects stormwater runoff and infiltrates it into the ground. The solid pipe will go closest to the house and the perforated pipe will go closest to the dry well. Dig along each side of the standard pipe. It is a covered porous walled chamber that allows water to slowly soak into the ground that is percolate dissipating into the groundwater.

Important design criteria and considerations for dry wells are listed below. Controlling rain run off with this old house landscape contractor roger cook. Use the shovel to cut into the soil just underneath the grass and move the top layer to a tarp. 2 position the dry well 10 feet 3 0 m from the downspout.

That way the grass can be put back in place once the trench is dug. Start with two 10 foot lengths of standard pipe then lay out two 10 foot lengths of perforated pipe.