ABSTRACT
An evapotranspiration (ET) system is a disposal system which is designed for disposal of septic tank effluent to the atmosphere rather than the soil. Because the system operates independently of the soil, any limiting characteristics of the soil do not affect the ET bed's operation. There are two basic types of ET beds: the lined ET and the evapotranspiration absorption (ETA) bed. ETA systems use a combination of ET and soil absorption to dispose of the sewage effluent. These systems have a much better reputation than the ET systems because they are generally cheaper and because they allow a greater margin of safety in terms of their ability to handle temporary overloads without failure. ET systems have been made to work in the northern United States, in the snow-clad Rocky Mountains and in Canada, but use of these systems is limited in general practice.
