Every conventional septic tank-drainfield system will fail at some point. Florida has one of the highest system failure rates mainly due to high water tables and weather. In a septic tank-drainfield system, failure doesn’t occur because the tank quits working. Failure is direct result of the soils being “plugged up” with a biomat that develops over time. The biomat consists of anaerobic bacteria and their by-products. The biomat develops as the bacteria in the soil breaks down the nutrients and contaminants in the wastewater. Once the biomat covers the entire absorption area in the drainfield, water has a hard time percolating or moving down through the soil. At this point, your drainfield is in failure and is in need of replacement. When a drainfield fails, the typical symptom is slow plumbing, gurgling sounds or a back up into the house. If your system has a pump in it, a blowout in the yard typically occurs.
A septic tank-drainfield system can also fail as a result of the system being designed by an individual who poses a certification or professional license that enables them to design systems but lack the proper training and experience. Many septic tank-drainfield systems fail because the soil conditions were not accurately determined and documented. This is why it is advantageous to have a certified professional soil scientist perform the site and soil investigation. If your system fails within a year or two of installation, failure is likely a result of hydraulic overload. Hydraulic overload is where too much water is going through the system.