Since solids will continue to build up at the bottom of the tank(s), it is imperative that the "septic tank be pumped out periodically." Most people recommend servicing your system every 3-5 years depending on size, use and soil conditions. Remember, sludge is not biodegradable, if it's not pumped out, sludge will accumulate until it overflows into the secondary tank or absorption field.
It is important to get the septic tank cleaned before the sludge level gets high enough so that any of the solid material at the bottom or the semi-solid scum at the top can flow into the drainage field. This will quickly clog the drainage pipes and the soil into which they drain. If this happens the only cure would be to dig up and replace the entire drainage field.
Make certain there are live bacteria in your system at all times. The bacteria's job is to digest all organic waste matter into the system. If there are no bacteria in your system it will simply act as a holding tank for your waste. It becomes full and natural digestion will not occur. That is when the system will usually back up.
Bacteria are killed off or overrun because of:
Excessive quantities of detergents, laundry waste, bleach, household chemicals and caustic drain openers.
Garbage disposal grinds, which substantially increase the accumulation of solids.
Disposal of items not biodegradable in the system (plastic, ect)
Disposal of excessive amounts of grease and fats, which are biodegradable but need particular types of bacteria to digest them.
Disposal of cigarette butts, sanitary napkins, which are also biodegradable but are not readily decomposable.
Too many people using a smaller / inadequate or failing system.
If you have no bacteria in your system and you add enzymes to the system, it simply will not help and your system will still not work. Enzymes are simply a catalyst for bacteria. If there are no bacteria in your system, why use enzymes?
From time to time, you should add "100 % Natural LIVE ADULT BACTERIA" to your system. Do not add just any kind of bacteria. Call your septic professional. He can add adult bacteria that are 'FACULTATIVE" which will work with or without oxygen.
[Please refer back to where we told you that "Bacterial action goes on at the bottom of the septic tank."] A facultative bacteria is one that would be useful in situations that have air and in situations where there is no air (anaerobic situations). The bottom of the septic tank has no oxygen and therefore needs anaerobic bacteria.