Tennessee Septic System Exam:
Questions With Correct
Solutions.LATEST EXAM 2025/2026
what is the purpose of a septic tank? - ANSWER-removes solid
materials from waste water and to filter water before it returns to the
water table
why is a septic tank compartmentalized? - ANSWER-to break down and
destroy the materials deposited in the septic tank
what are the components of a typical septic system? - ANSWER-
household collection system, septic tank, effluent distribution, drain
field, replacement area
what are the three fractions of a septic tank? - ANSWER-scum,
effluent, sludge
1|Page
,what is scum? - ANSWER-fats, oil and grease that float to top of septic
tank, lighter than water
what is effluent? - ANSWER-semi-treated waste water that comprised
majority of materials in septic tank
what is sludge? - ANSWER-solids which collect at the bottom of the
septic tank where most bacteria lives, inorganic
what are the two main cause of septic tank failure? - ANSWER-clogging
of distribution system or disruption of septic tank bacteria
what is the perfect soil type of a septic system and why? - ANSWER-
course granular because it drains well
percolation test - ANSWER-determines the absorption rate of soil for a
septic drain field or "leach field"
septic tank - ANSWER-typically underground, sewage is collected and
allowed to decompose through bacterial activity before draining by
means of a leach field,
raw sewage - ANSWER-effluent, sewer water, waste, waste material,
waste matter, waste product
2|Page
,distribution box - ANSWER-a container located at the outlet of a septic
tank to distribute the effluent evenly in the absorption field
leach field - ANSWER-removes contaminants and impurities from the
liquid that emerges from a septic tank
baffle - ANSWER-part of a septic tank's inlet and outlet piping. Helps
with the flow of wastewater
All tanks must have: - ANSWER-2 compartments
All tanks whether pre-manufactured or constructed on site shall be
constructed so that the length is ___________ compared to the width. -
ANSWER-at least one and one- half (1 1/2) times... "to the width."
Septic Tanks may be made of: - ANSWER-Concrete, Plastic, fiberglass,
or other materials as approved by the department.
Tank compartment partitions will be located: - ANSWER-Not less than
two-thirds or more than three-fourths the Length of the tank from the
Inlet end.
Compartment partitions will be constructed so a pass-thru hole or slot
equal to or greater than the diameter of the inlet pipe is positioned
below the liquid surface with a _____________________________. -
3|Page
, ANSWER-Minimum 25% to a maximum of 50% of the total liquid
depth.
Total liquid depth for larger poured-in-place tanks shall have a
maximum of ______________inches - ANSWER-66 inches
True or False: Walls and bottom of poured-in-place septic tanks must
be reinforced. - ANSWER-True
How can a Septic tank be reinforced? - ANSWER-six inch by 6 inch
(6"x6") No.10 gage welded steel reinforcing wire OR fibrous
reinforcing material conforming to ASTM specifications for such
materials.
How must Tank Lids be Reinforced? - ANSWER-using three-eights steel
reinforcing rods (rebar) which shall be spaced twelve inches (12") on
center each way extending a minimum of two and one half (2 1/2")
inches and a maximum of three (3") from the outside edge of the tank
lid.
In general, the tank must be able to withstand a uniform live load of
______________________ pounds per square foot in addition to all
loads to which an underground tank is normally subjected. - ANSWER-
150
4|Page
Questions With Correct
Solutions.LATEST EXAM 2025/2026
what is the purpose of a septic tank? - ANSWER-removes solid
materials from waste water and to filter water before it returns to the
water table
why is a septic tank compartmentalized? - ANSWER-to break down and
destroy the materials deposited in the septic tank
what are the components of a typical septic system? - ANSWER-
household collection system, septic tank, effluent distribution, drain
field, replacement area
what are the three fractions of a septic tank? - ANSWER-scum,
effluent, sludge
1|Page
,what is scum? - ANSWER-fats, oil and grease that float to top of septic
tank, lighter than water
what is effluent? - ANSWER-semi-treated waste water that comprised
majority of materials in septic tank
what is sludge? - ANSWER-solids which collect at the bottom of the
septic tank where most bacteria lives, inorganic
what are the two main cause of septic tank failure? - ANSWER-clogging
of distribution system or disruption of septic tank bacteria
what is the perfect soil type of a septic system and why? - ANSWER-
course granular because it drains well
percolation test - ANSWER-determines the absorption rate of soil for a
septic drain field or "leach field"
septic tank - ANSWER-typically underground, sewage is collected and
allowed to decompose through bacterial activity before draining by
means of a leach field,
raw sewage - ANSWER-effluent, sewer water, waste, waste material,
waste matter, waste product
2|Page
,distribution box - ANSWER-a container located at the outlet of a septic
tank to distribute the effluent evenly in the absorption field
leach field - ANSWER-removes contaminants and impurities from the
liquid that emerges from a septic tank
baffle - ANSWER-part of a septic tank's inlet and outlet piping. Helps
with the flow of wastewater
All tanks must have: - ANSWER-2 compartments
All tanks whether pre-manufactured or constructed on site shall be
constructed so that the length is ___________ compared to the width. -
ANSWER-at least one and one- half (1 1/2) times... "to the width."
Septic Tanks may be made of: - ANSWER-Concrete, Plastic, fiberglass,
or other materials as approved by the department.
Tank compartment partitions will be located: - ANSWER-Not less than
two-thirds or more than three-fourths the Length of the tank from the
Inlet end.
Compartment partitions will be constructed so a pass-thru hole or slot
equal to or greater than the diameter of the inlet pipe is positioned
below the liquid surface with a _____________________________. -
3|Page
, ANSWER-Minimum 25% to a maximum of 50% of the total liquid
depth.
Total liquid depth for larger poured-in-place tanks shall have a
maximum of ______________inches - ANSWER-66 inches
True or False: Walls and bottom of poured-in-place septic tanks must
be reinforced. - ANSWER-True
How can a Septic tank be reinforced? - ANSWER-six inch by 6 inch
(6"x6") No.10 gage welded steel reinforcing wire OR fibrous
reinforcing material conforming to ASTM specifications for such
materials.
How must Tank Lids be Reinforced? - ANSWER-using three-eights steel
reinforcing rods (rebar) which shall be spaced twelve inches (12") on
center each way extending a minimum of two and one half (2 1/2")
inches and a maximum of three (3") from the outside edge of the tank
lid.
In general, the tank must be able to withstand a uniform live load of
______________________ pounds per square foot in addition to all
loads to which an underground tank is normally subjected. - ANSWER-
150
4|Page
