Septic Tanks and Effluent Soakaways

Septic Tanks

If the property is unable to be connected to the mains sewer, a septic tank will be needed. The tank will need to be emptied at least once every 12 months in order to prevent a build up of solids in the tank.

This build up of solids can then enter the soakaway system and over a short period of time, cause the gravel in the soakaway  to block, rendering the system unable to work as it should.

Effluent Soakaways

The basic principle of a soak away system is to disperse septic effluent into the subsoil. The size of the soak away is determined by:-

  • The size of the property and number of residents that the tank is serving.
  • The type of sewage system i.e septic tank or sewage treatment plant.
  • The porosity of the subsoil.

To find the suitability of the subsoil a porosity or “percolation test” will need to be carried out.

Porosity “percolation test”

This test will need to be carried out to determine the suitability of the proposed area for  a soak away system and he the length of soak away required.

A typical test involves excavation of three test hole to an accurate size and depth. The hole is filled with water to a set level and the rate of drainage is recorded a number of times over a 24 hour period. The average is then taken for the 3 holes.

These results will then tell us the suitability of the ground and the length required.

Heavy or clay soil ground is not suitable for a soak away system, so alternate methods will need to be sought.