Depending on the daily flow, the soil type (soil permiability) and groundwater table, there are several main types of subsurface discharge of final effluent and drain devices. The most common drain devices are: a soakage pit, a drainage trench and absorption bed. Depending on site conditions the drain devices can be made of a different construction materials and may have a different design, configuration and size. For example, the drain pit may be made of rainforced concrete rings, sand-polymeric rings, etc. Drainage may be made of gravel or chambers.