Soakaway tests

The soakaway or percolation test is used to determine if a new or replacement soakaway can be installed. There are two very different types of soakaway – foul water soakaways and surface water soakaways. Foul water soakaways deal with small volumes over a long period surface water deal with large volumes over a short duration.

Geoinvestigate conducts soakaway tests for surface water soakways in accordance with BRE 365 Soakaway Design. These tests are carried out in test pits dug to a depth of about 2m or 2.5m using a mini excavator with a 0.3m to 0.6m wide bucket.

Soil permeability is measured by filling the pit with water from a bowser and recording the length of time for 75% of the volume of water to drain away. Soil permeability can also be measured in boreholes.