Georgia has regulations covering the location, installation and operation of on-site sewage treatment systems that include rules governing a drain or absorption field.
All new installations of septic sewage systems must be inspected and receive a permit from a county health department within Georgia. The local sanitarian, from a county health department, must carry out an effective absorption rate test, where a percolation test is used. A rate of 20 minutes to 90 minutes per inch is classed as a good rate of absorption for a drain field.
A drain field uses the natural filtration of soil to remove harmful bacteria and pollutants from wastewater; Georgia calculates the amount of drainage needed by the number of bedrooms in a building. The peak water usage each day is classed as 150 gallons per bedroom, which a drainage field must be able to absorb without allowing sewage to enter groundwater supplies.
A septic sewage system must be installed, included hard pipes carrying wastewater to a drainage field by a contractor certified by the state. The location of a drain field is required to be determined using a soil sustainability analysis, which uses Soil and Water Conservation Commission maps to determine the type of soil in different areas of Georgia.