When septic tank failure occurs it is usually because of problems with the drainfield rather than the septic tank itself. There is not much that can go wrong with a septic tank as long as it is water tight and pumped out on a regular basis.
Drainfield failure can happen for many reasons, such as very heavy rainfall, tree roots penetrating the drainlines or vehicles driving over the field and breaking the pipes. Sometimes the tightline, which connects the tank and the drainfield, has broken. But two of the most common causes of drainfield and hence septic tank failure are overloading with water and overloading with organic waste. Overloading with water happens when the size of the septic tank is just not enough for the household it belongs to.
If your drainfield is not working, what can you do about it? Your first action should be to consult a qualified septic tank service because septic tank failure is a job for the professionals. A non-functional drainfield is a health hazard and should be taken seriously.
In cases of physical damage, repair might be quite easy. Your septic tank service may only need to repair the crushed or broken pipe, remove any troublesome tree roots or replace faulty baffles in the septic tank.
Sometimes a drainfield overloaded with water can recover if a strict policy of water conservation is observed but it requires a lot of commitment on behalf of the family. It usually takes a 30 percent reduction in water use to reverse the septic tank failure and allow the drainfield to recover.
If corrective measures fail then your septic tank service will probably advise construction of a new soil absorption system. New systems can be placed either in an isolated area so the old set-up is not disturbed or located in between the existing trenches if there is enough room. These extra lines are effectively part of an alternating drainfield system.