Septic tanks work in conjunction with drainage fields to filter domestic sewage effluent. They are a storage facility in part, allowing microbes to break down solid matter, as well as allowing the expulsion dispersal of liquid effluent into the surrounding sub-soil. Septic Tanks must be emptied every 3-5 years but throughout this period, filtered effluent is designed to drain through the subsoil beneath the residence. Therefore, it is imperative that ground conditions are suitable meeting the following requirements:

1. The soil will allow percolation at a sufficient pace as to remove effluent
     at a greater rate than that of influx into the system.

2. The subsoil structure allows the contamination to discharge efficiently
     and safely in such a way as to avoid ponding.

The main obstacle to achieving these conditions is usually the level of the water table. Where the water table is high, neither of the conditions can be satisfied and consequently, such properties are not suitable for septic tank installations.

Where septic tanks have failed, AES-Marconi can investigate on behalf of clients to determine the reasons behind such septic tank failures, recommend a remedial strategy to alleviate the problem and undertake the necessary remedial works if required to do so.