There are many reasons which may cause a septic tank to flood and these can range from something as simple as an outlet ‘dip pipe’ being blocked to more serious problems involving the receiving soakaway system.
The effluent level inside a septic tank should be at the level of the outlet pipe. In some instances either the inlet or outlet pipes for a septic tank can become blocked with materials such as fat or tissue. If the inlet ‘dip pipe’ becomes blocked this would result in the foul drainage to the tank flooding, and this is more common in older traditionally built septic tanks. If the outlet ‘dip pipe’ becomes blocked this would result in both the septic tank and incoming foul drainage pipe work flooding. In some cases it is only necessary to clear the blockage with drainage rods.
The most common cause for a septic tank flooding is due to the receiving soakaway and not the septic tank. If a soakaway fails and prevents the effluent from percolating through the ground this will result in the soakaway, septic tank and the foul drainage pipe work surcharging. In some cases having a soakaway ‘jetted’ can resolve the failure of a soakaway, but in our experience it is often necessary to have the soakaway replaced.