Constructing a foul water drainage field requires specific rules and regulations you must stick to in order to abide by the law and dispose of foul water in a safe and correct way.
These steps give you guidance on how to install a drainage field to provide secondary treatment to the discharge from a septic tank.
Design and Construction
As per Building Regulations 2010 Drainage and Waste Disposal Part H:
- Drainage fields should be designed and constructed to ensure aerobic contact between the liquid effluent and the subsoil.
- Drainage fields should be constructed using perforated pipe, laid in trenches of a uniform gradient which should not be steeper than 1:200.
- Pipes should be laid on a 300mm layer of clean shingle or broken stone graded between 20mm and 50mm.
- Trenches should be filled to a level 50mm above the pipe and covered with a layer of non-woven geotextile to prevent the entry of silt. The remainder of the trench can be filled with soil; the distribution pipes should be laid at a minimum depth of 500mm below the surface.
Drainage trenches should be from 300mm to 900mm wide, with areas of undisturbed ground 2m wide being maintained between parallel trenches.
- An inspection or a sample chamber should be installed between the septic tank and the drainage field.
- Drainage fields should be set out as a continuous loop fed from the inspection chamber.
Contact JDP's Technical Support Team who will be able to assist you with further queries regarding septic drianage field construction.
Technical Support: 01228 794445
Building Regualtions Part H2 , 1.26-1.44