When a system is failing you may experience the issues listed above inside the home. It is also common for either the tank or drainfield to fail but not necessarily both. In a tank failure, holes/corrosion caused by methane gas may be present, the best way to know if your tank is failing is to have it pumped unless the issues are clearly visible. When a drainfield is in failure typically there’s sewage back-up into the home due to the fact that the field is no longer accepting water and is saturated. Each home is different therefore each system is different; the only way to know is to contact a septic contractor or your local health department for evaluation.