VIRGINIA SEPTIC REPAIR CONTRACTOR EXAM –
350 PRACTICE QUESTIONS AND CORRECT
ANSWERS WITH DETAILED RATIONALES
Section 1: System Fundamentals & Components (Questions 1–50)
1. What is the primary function of a conventional onsite sewage system?
A) Provide potable water to the household
B) Treat and disperse household wastewater safely into the soil
C) Control stormwater runoff from the property
D) Pump sewage directly to a municipal treatment plant
Correct Answer: B
Rationale: Conventional systems rely on biological and physical processes to
treat wastewater and disperse effluent into the soil, protecting groundwater
and public health.
2. Which component of a conventional system temporarily stores wastewater
and allows solids to settle?
A) Drainfield
B) Septic tank
C) Distribution box
D) Pump chamber
,Correct Answer: B
Rationale: The septic tank provides primary treatment by allowing solids to
settle as sludge and fats/oils to float as scum, while clarified effluent exits to
the Drainfield.
3. What does a percolation (perc) test measure?
A) Groundwater level
B) Soil absorption rate for wastewater
C) Pipe diameter needed for the system
D) Septic tank capacity
Correct Answer: B
Rationale: Perc tests determine how quickly soil can absorb effluent, which is
critical for sizing the drain field and ensuring proper system function.
4. What is the minimum separation required between the bottom of a drain
field and the seasonal high-water table in Virginia?
A) 12 inches
B) 24 inches
C) 36 inches
D) 48 inches
Correct Answer: B
Rationale: Virginia regulations require a minimum of 24 inches of unsaturated
soil between the drainfield bottom and the seasonal high-water table to
ensure adequate treatment.
,5. What is the purpose of a septic tank's baffle?
A) To aerate the wastewater
B) To prevent solids from entering the drainfield
C) To remove nitrogen from the effluent
D) To filter out pathogens
Correct Answer: B
Rationale: Baffles at the inlet and outlet of the septic tank prevent scum and
floating solids from exiting the tank and clogging the drainfield.
6. Which type of soil is LEAST suitable for a conventional onsite sewage
system?
A) Sandy soil
B) Loamy soil
C) Clay soil
D) Gravelly soil
Correct Answer: C
Rationale: Clay soil has very low permeability, causing effluent to pond on the
surface or back up into the system rather than properly absorbing into the
ground.
7. What is the primary purpose of the distribution box in a conventional
drainfield?
A) To pump effluent to a mound system
B) To evenly distribute effluent to the drainfield trenches
C) To filter solids from the effluent
, D) To aerate the wastewater
Correct Answer: B
Rationale: The distribution box ensures uniform flow to all sections of the
drainfield, preventing overloading of any single trench.
8. How often should a residential septic tank typically be inspected?
A) Every 6 months
B) Every 1–3 years
C) Every 5 years
D) Only when problems arise
Correct Answer: B
Rationale: Regular inspections every 1–3 years help identify problems early
and prevent costly failures.
9. What is the minimum horizontal distance between a septic tank and a
private well in Virginia?
A) 50 feet
B) 75 feet
C) 100 feet
D) 150 feet
Correct Answer: A
Rationale: Virginia regulations require a minimum 50foot separation between
a septic tank and a private well to protect groundwater from contamination.
350 PRACTICE QUESTIONS AND CORRECT
ANSWERS WITH DETAILED RATIONALES
Section 1: System Fundamentals & Components (Questions 1–50)
1. What is the primary function of a conventional onsite sewage system?
A) Provide potable water to the household
B) Treat and disperse household wastewater safely into the soil
C) Control stormwater runoff from the property
D) Pump sewage directly to a municipal treatment plant
Correct Answer: B
Rationale: Conventional systems rely on biological and physical processes to
treat wastewater and disperse effluent into the soil, protecting groundwater
and public health.
2. Which component of a conventional system temporarily stores wastewater
and allows solids to settle?
A) Drainfield
B) Septic tank
C) Distribution box
D) Pump chamber
,Correct Answer: B
Rationale: The septic tank provides primary treatment by allowing solids to
settle as sludge and fats/oils to float as scum, while clarified effluent exits to
the Drainfield.
3. What does a percolation (perc) test measure?
A) Groundwater level
B) Soil absorption rate for wastewater
C) Pipe diameter needed for the system
D) Septic tank capacity
Correct Answer: B
Rationale: Perc tests determine how quickly soil can absorb effluent, which is
critical for sizing the drain field and ensuring proper system function.
4. What is the minimum separation required between the bottom of a drain
field and the seasonal high-water table in Virginia?
A) 12 inches
B) 24 inches
C) 36 inches
D) 48 inches
Correct Answer: B
Rationale: Virginia regulations require a minimum of 24 inches of unsaturated
soil between the drainfield bottom and the seasonal high-water table to
ensure adequate treatment.
,5. What is the purpose of a septic tank's baffle?
A) To aerate the wastewater
B) To prevent solids from entering the drainfield
C) To remove nitrogen from the effluent
D) To filter out pathogens
Correct Answer: B
Rationale: Baffles at the inlet and outlet of the septic tank prevent scum and
floating solids from exiting the tank and clogging the drainfield.
6. Which type of soil is LEAST suitable for a conventional onsite sewage
system?
A) Sandy soil
B) Loamy soil
C) Clay soil
D) Gravelly soil
Correct Answer: C
Rationale: Clay soil has very low permeability, causing effluent to pond on the
surface or back up into the system rather than properly absorbing into the
ground.
7. What is the primary purpose of the distribution box in a conventional
drainfield?
A) To pump effluent to a mound system
B) To evenly distribute effluent to the drainfield trenches
C) To filter solids from the effluent
, D) To aerate the wastewater
Correct Answer: B
Rationale: The distribution box ensures uniform flow to all sections of the
drainfield, preventing overloading of any single trench.
8. How often should a residential septic tank typically be inspected?
A) Every 6 months
B) Every 1–3 years
C) Every 5 years
D) Only when problems arise
Correct Answer: B
Rationale: Regular inspections every 1–3 years help identify problems early
and prevent costly failures.
9. What is the minimum horizontal distance between a septic tank and a
private well in Virginia?
A) 50 feet
B) 75 feet
C) 100 feet
D) 150 feet
Correct Answer: A
Rationale: Virginia regulations require a minimum 50foot separation between
a septic tank and a private well to protect groundwater from contamination.
