A septic tank is usually one half of a wastewater treatment system, the other half being the drainage field that follows it. A septic tank is a simple watertight vessel, the purpose of which is to hold incoming wastewater from the property served for a long enough time to allow solids to either settle to the bottom of the tank or float to the surface and, either way, be stored in the tank until such time as they can be removed and transported to a municipal sewage treatment works for further treatment.
Septic tanks come in various shapes, sizes and materials and if you need help to size one just call us.
In England and Wales the liquid that flows forward from the septic tank – the “primary treated effluent” - must be put into a drainage field (or “soakaway”) but in Scotland, subject to SEPA’s assessment and approval, it can be discharged to a watercourse.
In England the maximum volume of septic tank effluent that can be discharged “to ground” through a drainage field without a permit from the Environment Agency is 2000 litres per day, the equivalent of about 13 people’s daily wastewater production. Regardless of volume, a permit from SEPA is needed in Scotland and in Wales an exemption from having to apply for a permit must be registered.
Have a look, too, at the other half of the system you’ll need on our Septic Tank Drainage Field pages.