Common Causes of Septic System Failure

A septic system includes the source, the septic tank, the drain field and the soil beneath the drain field. Although septic tanks are given a big importance, the drain field is the most important part. Septic tank failure is a nuisance and a health hazard and can result in the spread of diseases and causes pollution. One should know the causes which lead to septic system failure and should precautions should be taken accordingly.

Age of the septic field

The age of the drain field is a major factor because even if the drain field is well maintained, it will start to clog at some point and have to be replaced. It depends on the size of the field, soil characteristics, groundwater, materials used for the construction etc. The average age of a drain field is 25 years, depending on its usage and maintenance.


Soil clogging is a major problem around the drain field trenches. Tree roots can infiltrate the drain field. If the septic tank is not pumped routinely, sludge is formed in the pipes, which can lead to blockage.


A common reason for system failure is over usage of water. A septic system is designed to handle a specific amount of water. When the flow rate is exceeded, the extra water starts to pile up and flows into the yard and around the house. This problem is mainly faced due to any leakage in pipes, which leads to the constant dripping of water which can get logged due to oversaturation. Using more water than the soil can absorb is a major issue. Even the water draining from the roofs and rainwater is lead to the absorption area which leads to a saturation point beyond which the soil cannot hold water. Hence, the waste water might back up into the house which can create a health hazard and bad odor.

Septic tank failures

The septic tank baffles are sometimes made of steel. When it is in constant contact with water and air, corrosion can occur which can damage the whole septic system. The tank baffles should be properly coated to prevent rusting.

Physical damage

Vehicles and permanent structures built over the pipes of the septic system can crush the pipes which can lead to breakage. Tree roots may clog the drain lines, so it is advised to remove trees from around 20-25 ft. from the drain field.

Poor maintenance

The septic tank should be pumped at least once in every 3 years to avoid the formation of sludge. We should avoid solids from reaching the drain field as they may clog small pores and spaces in the soil.

These are the major causes of septic tank failure and proper precautions should be taken in order to avoid it. If any signs of septic system failure arise, it should be properly inspected by professionals to avoid further nuisance.