What is Drywell?

Definition of Drywell in Construction

The construction of a special area for storm water to drain into on a project. This area will normally consist of an excavation with a filter membrane installed along the exterior of the excavation. This filter membrane will prevent the interior of the excavation from becoming contaminated with small particles of soil or silt and will keep the stone, which is used to fill this excavation, clean.

The intent of a drywell is to remain dry, until the storm line entering the drywell becomes active. If the line is distributing water into the drywell, the capacity of the drywell is calculated to allow water to retain within the drywell and percolate out into the surrounding soils in a controlled fashion. This will resolve the issue of a substantial amount of ground water being deposited on the surface, surrounding a project, and causing water issues. The use of the drywell technique of storm water retaining has been in existence for hundreds of years and is a very popular method of storm water control.