If the liquid effluent cannot soak into the soil surrounding the leach
field, sewage may back up into the system and overflow into
the house or puddle on the surface of the ground. There are several
possible causes for this problem.
1. Poor Soil Conditions; Faulty Design or Installation
A leaching system placed in unsuitable soil, a system that is too small
for the house it serves, or an improperly constructed system
may lead to early failure.
2. Soil Clogging
If sludge or scum is allowed to escape into the distribution box and
from there into the leach field, the soil will quickly become
clogged. If this happens, the liquid will no longer soak, or percolate,
into the soil. This condition can be caused by broken baffles in
the septic tank that allow sludge or scum to escape. Failure to have
the tank pumped can also lead to a situation where the sludge
and scum overwhelm the baffles.
3. High Water Table
During wet, or abnormally wet, seasons groundwater may rise into the
leach field and force sewage upward to the ground
surface. This condition may mean the system has to be re-installed
at a higher level. It may also be possible to intercept the high
groundwater with a series of drains around the system called "curtain
drains".
4. Roots
The roots of trees and bushes planted too close to the system can sometimes
enter and block the pipes of the system. Removal of
the plants and clearing the pipes of the roots is usually required.
5. Physical Damage
Trucks or heavy equipment passing over the system can damage pipes
and joints to the point of rendering the system inoperable.
You should be aware of the location of the system and direct traffic
to avoid such damage.