So what is the difference between a drain field and leach field? Not a lot. As a matter of fact, there is no difference at all since “drain field” is just another way of saying “leach field” and vice versa.
Just about every septic system will include a drainage area where the liquids within the main tank are allowed to pass through during the cleansing or purification process. In a drain field system, you normally have a septic tank, distribution box and later lines which make up your “field”. The field area may be crafted of tile, tubing or PVC piping and is surrounded by gravel and in some cases, special permeable soils are hauled in to help with the systems effectiveness. This cleansing takes place in the gravel area where high colony counts of bacteria continually break down small particles of waste into water and gas. The water is pulled down to the water table by gravity as it leaves your drain field and bacteria in the soils continue to purify all the way down, sometimes hundreds of feet deep!
Modern drain fields are constructed of PVC piping which have small holes every few inches to allow the effluent (liquid) to evenly seep into the ground area where the lines are laid out. This cycle continues indefinitely as long as your drain field allows the liquid to pass freely. The drain field type design has been used to provide onsite waste treatment for hundreds of homeowners around the globe and remains one of the most successful systems to date.