Soakaways are used to direct surface run-off from roof drainage or sewage processing plants it into the sub-soil.  They are usually constructed in areas of low permeability and where run-off can not be disposed of into existing sewers or watercourses.

It is necessary to carry out percolation tests to determine the permeability of the soil.  There are 4 different ways H.D. Services construct soakaways:


A conventional soakaway consists of a partially perforated chamber which allows the draining of water into the surrounding soil.


Land drainage consists of perforated pipework laid horizontally to allow soakage into the ground.


These systems comprise of land drains which run to a ditch. Generally, they are laid in less permeable soils to allow for times when increased rainfall may water log the ground surrounding the land drain, meaning that the excess water can run off into the ditch.


A borehole soakaway is used in areas where impermeable soils (clay) overlie permeable strata (chalk).  In these cases the soakage must take place at depth and so a deep bore liner is used.  The water is transported from a sealed storage chamber to the borehole by small diameter plastic or steel pipe.  By discharging run-off into fissures at depth, the risk of shallow subsidence is reduced.  We usually drill Soakaway boreholes with a 6″ finished diameter, but can be constructed to different diameters if specified.





Clean surface water can go straight into the ground. However, there are restrictions regarding the disposal of effluent from septic tanks and sewage treatment systems, as no matter how well treated the effluent is, it is not clean water and presents a risk to people and the environment. All major sewage treatment effluent discharges must be registered with the Environment Agency. This applies to both new and replacement installations.

In all cases the Environment Agency should be consulted to determine whether any restrictions apply.  Aquifers provide a large percentage of drinking water in the south east, meaning that they have to be protected against contamination.  If contamination were to occur, the drinking water could be affected. If found guilty of contamination, fines and imprisonment could be imposed upon both the contractor and the property owner who commissioned the work. Further information regarding the government stance on groundwater protection can be found here. Information on the National House Building Council Standards regarding foul water and run-off draining can be found here