Septic License
1. What is the primary function of a septic tank?
A. To treat wastewater completely
B. To separate solids from liquids and begin treatment
C. To allow direct discharge of effluent into groundwater
D. To filter all pathogens from wastewater
✅ Answer: B. To separate solids from liquids and begin treatment
Explanation: The septic tank allows solids to settle and undergo anaerobic digestion
while allowing effluent to flow into the drain field.
2. How often should a typical residential septic tank be pumped?
A. Every 1–2 years
B. Every 3–5 years
C. Every 7–10 years
D. Never, if the system is working
✅ Answer: B. Every 3–5 years
Explanation: Regular pumping prevents buildup of solids that can clog the system
and cause failure.
3. What component follows the septic tank in a traditional system?
A. Grease trap
B. Chlorinator
C. Drainfield or leach field
D. Holding tank
,✅ Answer: C. Drainfield or leach field
Explanation: The drainfield distributes effluent into the soil for final treatment and
disposal.
4. Which of the following soil types is least suitable for a conventional drainfield?
A. Sandy loam
B. Silt loam
C. Clay
D. Loamy sand
✅ Answer: C. Clay
Explanation: Clay soils have low permeability and can prevent proper effluent
absorption.
5. What is the purpose of a distribution box (D-box)?
A. To treat effluent before it reaches the drainfield
B. To collect solids from wastewater
C. To evenly distribute effluent to multiple trenches
D. To aerate wastewater
✅ Answer: C. To evenly distribute effluent to multiple trenches
Explanation: A D-box ensures that each trench in the drainfield receives equal flow.
6. When inspecting a septic tank, what does a strong odor of hydrogen sulfide
indicate?
A. Proper anaerobic digestion
B. Aerobic activity
C. System overuse
D. Possible septic tank malfunction or buildup of gases
✅ Answer: D. Possible septic tank malfunction or buildup of gases
,Explanation: Strong odors may indicate excessive solids, poor digestion, or lack of
venting.
7. What is the minimum setback distance from a well to a septic system in most
states?
A. 10 feet
B. 25 feet
C. 50 feet
D. 100 feet
✅ Answer: D. 100 feet
Explanation: To prevent groundwater contamination, regulations usually require a
100-foot setback.
8. Effluent filters are installed in septic systems to:
A. Block grease and oil
B. Prevent solids from entering the drainfield
C. Treat the wastewater
D. Filter out bacteria
✅ Answer: B. Prevent solids from entering the drainfield
Explanation: Effluent filters reduce clogging in the drainfield by trapping suspended
solids.
9. A mound system is typically used when:
A. The water table is deep
B. The site has sandy soil
C. There is insufficient soil depth to groundwater
D. There is no need for additional treatment
✅ Answer: C. There is insufficient soil depth to groundwater
, Explanation: Mound systems elevate the drainfield to provide adequate treatment
above shallow groundwater.
10. What is the primary cause of septic system failure?
A. Freezing temperatures
B. Improper household water pressure
C. Lack of regular maintenance/pumping
D. Over-aeration of the tank
✅ Answer: C. Lack of regular maintenance/pumping
Explanation: Solids buildup can clog pipes and fields, leading to costly failures.11.
What is the typical liquid capacity range of a residential septic tank?
A. 100–300 gallons
B. 500–750 gallons
C. 750–1500 gallons
D. 2000–4000 gallons
✅ Answer: C. 750–1500 gallons
Explanation: Most residential systems use septic tanks within this range, depending
on household size.
12. What type of bacteria is primarily responsible for breaking down solids in a septic
tank?
A. Aerobic bacteria
B. Anaerobic bacteria
C. Thermophilic bacteria
D. Photosynthetic bacteria
✅ Answer: B. Anaerobic bacteria
Explanation: Anaerobic bacteria break down organic waste in the absence of oxygen
within the septic tank.
1. What is the primary function of a septic tank?
A. To treat wastewater completely
B. To separate solids from liquids and begin treatment
C. To allow direct discharge of effluent into groundwater
D. To filter all pathogens from wastewater
✅ Answer: B. To separate solids from liquids and begin treatment
Explanation: The septic tank allows solids to settle and undergo anaerobic digestion
while allowing effluent to flow into the drain field.
2. How often should a typical residential septic tank be pumped?
A. Every 1–2 years
B. Every 3–5 years
C. Every 7–10 years
D. Never, if the system is working
✅ Answer: B. Every 3–5 years
Explanation: Regular pumping prevents buildup of solids that can clog the system
and cause failure.
3. What component follows the septic tank in a traditional system?
A. Grease trap
B. Chlorinator
C. Drainfield or leach field
D. Holding tank
,✅ Answer: C. Drainfield or leach field
Explanation: The drainfield distributes effluent into the soil for final treatment and
disposal.
4. Which of the following soil types is least suitable for a conventional drainfield?
A. Sandy loam
B. Silt loam
C. Clay
D. Loamy sand
✅ Answer: C. Clay
Explanation: Clay soils have low permeability and can prevent proper effluent
absorption.
5. What is the purpose of a distribution box (D-box)?
A. To treat effluent before it reaches the drainfield
B. To collect solids from wastewater
C. To evenly distribute effluent to multiple trenches
D. To aerate wastewater
✅ Answer: C. To evenly distribute effluent to multiple trenches
Explanation: A D-box ensures that each trench in the drainfield receives equal flow.
6. When inspecting a septic tank, what does a strong odor of hydrogen sulfide
indicate?
A. Proper anaerobic digestion
B. Aerobic activity
C. System overuse
D. Possible septic tank malfunction or buildup of gases
✅ Answer: D. Possible septic tank malfunction or buildup of gases
,Explanation: Strong odors may indicate excessive solids, poor digestion, or lack of
venting.
7. What is the minimum setback distance from a well to a septic system in most
states?
A. 10 feet
B. 25 feet
C. 50 feet
D. 100 feet
✅ Answer: D. 100 feet
Explanation: To prevent groundwater contamination, regulations usually require a
100-foot setback.
8. Effluent filters are installed in septic systems to:
A. Block grease and oil
B. Prevent solids from entering the drainfield
C. Treat the wastewater
D. Filter out bacteria
✅ Answer: B. Prevent solids from entering the drainfield
Explanation: Effluent filters reduce clogging in the drainfield by trapping suspended
solids.
9. A mound system is typically used when:
A. The water table is deep
B. The site has sandy soil
C. There is insufficient soil depth to groundwater
D. There is no need for additional treatment
✅ Answer: C. There is insufficient soil depth to groundwater
, Explanation: Mound systems elevate the drainfield to provide adequate treatment
above shallow groundwater.
10. What is the primary cause of septic system failure?
A. Freezing temperatures
B. Improper household water pressure
C. Lack of regular maintenance/pumping
D. Over-aeration of the tank
✅ Answer: C. Lack of regular maintenance/pumping
Explanation: Solids buildup can clog pipes and fields, leading to costly failures.11.
What is the typical liquid capacity range of a residential septic tank?
A. 100–300 gallons
B. 500–750 gallons
C. 750–1500 gallons
D. 2000–4000 gallons
✅ Answer: C. 750–1500 gallons
Explanation: Most residential systems use septic tanks within this range, depending
on household size.
12. What type of bacteria is primarily responsible for breaking down solids in a septic
tank?
A. Aerobic bacteria
B. Anaerobic bacteria
C. Thermophilic bacteria
D. Photosynthetic bacteria
✅ Answer: B. Anaerobic bacteria
Explanation: Anaerobic bacteria break down organic waste in the absence of oxygen
within the septic tank.
