Failing Septic Systems are an unpleasant, and often expensive fact of life for many homeowners. With increased awareness and tightening legislation regarding onsite wastewater treatments systems, many "working" septic systems are actually failing, even though your toilets are flushing.
You see, septic systems are almost entirely hidden underground. The term "Out of Site, Out of Mind" comes to play here. For most people, as long as everything is flushing like it should, there is nothing to worry about. This, however, is often not the case.
It is very difficult to tell if your system is having problems by just opening the lid. To do a proper inspection, the tank needs pumped by a licensed septage hauler and inspected by a trained professional. Before pumping, the inspector will look for any defects near the top of the tank, including cracks, corrosion (on concrete tanks), warping (on poly tanks), root intrusion, and they will check the water level inside the tank. After pumping, then a more detailed inspection will follow. This includes taking photographs of the interior of the tank, and searching for any of the above defects.
Typically, when we see a failing system, it is due to a crack or corrosion on the concrete tank. Corrosion weakens the structural integrity of the concrete tank, posing a risk of collapsing in the ground. Cracks in the tank's walls also can pose risk of collapsing, but they are more likely to cause leaks. Tree roots show the inspector that the tank is no longer watertight, considering how it has allowed roots to enter the sealed tank. On poly tanks, poor installation often lead to the tanks changing shape inside the ground.
Unfortunately, many of the reasons for tank failure can not be prevented. Corrosion with concrete tanks starts as soon as the tank begins storing waste. Cracks happen due to improper installation, settling/shifting ground, or excessive pressure on the tank, like being driven over. Roots can be prevented by not planting anything near the system, but during dry periods, roots can travel a very long distance in search of water.
The best thing a homeowner can do to keep their system in good, working order, is to be mindful of the system itself. This means performing proper maintenance at regular intervals, doing visual inspections on an annual basis (at a minimum), and not flushing anything that may harm the system. If you, or a service technician identifies any issues with the system, its best to fix them sooner rather than later; waiting too long can result in total system failure. And a new system is not something many people want to deal with.