Why do I need to have my septic tank pumped?

To understand why your tank needs pumping on a regular basis, you need to know how the septic tank functions. As waste enters the tank:

The solids settle to the bottom where enzymes and bacteria start to break down the solids into a sludge
The oil/grease floats on top of the water forming a scum layer
1. If this is not cleaned regularly, it could cause two (2) major issues:
  1) The sludge could accumulate to the point that it blocks the inlet to the tank, thereby causing waste from the house to back up, even to the point where it could come up through drains on the lowest level.
  2) The sludge could accumulate to the point that it gets into the field lines and cause it to become clogged, which will prevent the water from percolating into the soil through the holes in the field lines. This will cause the tank to overflow and cause odors and wet spots in the yard. There is no way to repair the field lines once they become clogged. The only solution is to have them replaced.
  The time between cleanings is a function of tank size and the number of people living in the house.