What is a septic tank?

What is a septic tank or septic system?

A septic tank is a large holding tank where human waste can decompose into recyclable water or effluent and can be returned to nature. The environmentally dangerous elements can be pumped and transported by a truck with a vacuum cleaning device, and hauled away for proper disposal. Septic tanks have poisonous gasses and should never be entered.
The septic system is comprised of two parts: the tank, and the drain field or leach field. The waste water runs from the house into the tank, there it separates naturally into a scum layer which is floating on top and a sludge layer of heavier materials which sinks to the bottom.

Gases will eventually vent into the atmosphere as part of the septic tank’s plumbing system. The tank holds the solids to prevent them from leaching into the surrounding environment and allows the first stage of the bacterial process. Between the sludge and the scum is the relatively clear water (effluent) which is filtered to the distribution box or header pipe and ultimately to the drain field or leach bed which is an area of ground around the tank that can absorb the liquid. Problems occur when there is a blockage in the septic tank or the drain field becomes saturated and can no longer absorb the water or effluent.what is a septic tank

Question:  How do I know if my septic is full?
Answer:  Septic tanks are designed to be filled to the bottom of the outlet baffle, then water exits the tank into the drain field every time water enters the tank from the house.

Question: I  just had it pumped why is it full again?
Answer: The waste water flows into the tank, fills the tank, then flows into the drain field.  A 900 gallon tank Holds 900 gallons of water, then it goes to the drain field. If your drain field is not working septic water will back up into the house because it has no place to go.