Kentucky Certified Septic System Installer
Practice Exam with Practice Questions
And Corr
1. During a percolation test in a Kentucky soil with a high shrink-swell clay content,
the measured rate is 90 min/in. However, the soil profile reveals a 20-inch thick
smectitic clay layer over fractured limestone. According to Kentucky onsite sewage
disposal regulations, which of the following is the most appropriate action?
A. Proceed with a standard trench system sized using the 90 min/in rate.
B. Reject the site for a conventional system and require an alternative system designed
by a professional engineer.
C. Install a conventional system with increased trench spacing to compensate for clay.
D. Conduct a second percolation test after 30 days to confirm the rate.
Answer: B. Reject the site for a conventional system and require an alternative system
designed by a professional engineer.
Rationale: Kentucky regulations prohibit conventional systems in soils with percolation
rates slower than 60 min/in or with limiting layers that restrict effluent movement; smectitic
clay over fractured limestone poses a high risk of groundwater contamination and requires
an engineered alternative. Option A ignores the regulatory threshold and the limiting layer.
Option C does not address the fundamental unsuitability. Option D delays but does not
resolve the regulatory prohibition.
Page 1 of 84
,2. A proposed 4-bedroom home in Kentucky requires a septic system. Using the
Kentucky design flow of 120 gallons per bedroom per day and a soil application rate
of 0.4 gpd/ft², what is the minimum required absorption field area?
A. 800 ft²
B. 1,200 ft²
C. 1,600 ft²
D. 2,400 ft²
Answer: B. 1,200 ft²
Rationale: Design flow = 4 bedrooms × 120 gpd/bedroom = 480 gpd. Required area = 480
gpd ÷ 0.4 gpd/ft² = 1,200 ft². Options A, C, and D result from miscalculations or using
incorrect design flows or application rates.
Page 2 of 84
,3. An installer is preparing to install a septic tank in a area with a seasonal high water
table at 18 inches below the ground surface. Kentucky regulations require a minimum
separation of 24 inches between the bottom of the absorption field and the water table.
Which of the following is the most appropriate design modification?
A. Install a mounded system with the absorption field elevated above the natural grade.
B. Increase the size of the absorption field by 50% to compensate for the reduced
separation.
C. Install a curtain drain around the absorption field to lower the water table.
D. Use a concrete septic tank with a riser to the surface and proceed with a conventional
system.
Answer: A. Install a mounded system with the absorption field elevated above the
natural grade.
Rationale: A mounded system elevates the absorption field to achieve the required 24-inch
separation from the seasonal high water table, as allowed by Kentucky regulations. Option
B does not address the separation requirement. Option C may help but is not a guaranteed
solution and may not be approved without engineering. Option D does not resolve the
separation issue.
4. Which of the following best describes the primary function of a distribution box
(D-box) in a septic system absorption field?
A. To collect solids and prevent them from entering the absorption field.
B. To evenly distribute effluent to multiple drainfield lines.
C. To provide a means of measuring the volume of effluent entering the field.
D. To aerate the effluent before it enters the soil.
Answer: B. To evenly distribute effluent to multiple drainfield lines.
Rationale: A distribution box is designed to evenly distribute effluent to multiple drainfield
lines, ensuring uniform loading and preventing overloading of any single line. Option A
describes a septic tank's function. Option C is not a primary function. Option D is
incorrect; aeration occurs in aerobic treatment units.
Page 3 of 84
, 5. During an inspection of an existing septic system, an installer observes that the
effluent from the septic tank has a strong odor and contains significant solids. The
absorption field is not ponding. Which of the following is the most likely cause?
A. The septic tank is undersized for the home's occupancy.
B. The absorption field is failing and needs replacement.
C. The septic tank has not been pumped in over 10 years, leading to excessive sludge and
scum accumulation.
D. The distribution box is misaligned, causing uneven flow.
Answer: C. The septic tank has not been pumped in over 10 years, leading to excessive
sludge and scum accumulation.
Rationale: Excessive solids in the effluent indicate that the septic tank is not retaining
solids properly, often due to lack of maintenance and excessive sludge/scum buildup.
Option A could contribute but is less likely if the tank was properly sized originally. Option
B is not supported because the absorption field is not ponding. Option D would cause
uneven distribution, not solids carryover.
6. In Kentucky, which of the following is a requirement for the installation of a septic
system in a floodplain?
A. The system must be designed by a professional engineer and approved by the local
health department.
B. The system must be installed with a minimum 12-inch freeboard above the 100-year
flood elevation.
C. The system must be a mound system with a pump.
D. The system must be equipped with a backflow preventer on the outlet.
Answer: A. The system must be designed by a professional engineer and approved by
the local health department.
Rationale: Kentucky regulations require that septic systems in floodplains be designed by a
professional engineer and approved by the local health department to ensure protection of
public health and the environment. Options B, C, and D are not universal requirements and
may not be sufficient alone.
Page 4 of 84
Practice Exam with Practice Questions
And Corr
1. During a percolation test in a Kentucky soil with a high shrink-swell clay content,
the measured rate is 90 min/in. However, the soil profile reveals a 20-inch thick
smectitic clay layer over fractured limestone. According to Kentucky onsite sewage
disposal regulations, which of the following is the most appropriate action?
A. Proceed with a standard trench system sized using the 90 min/in rate.
B. Reject the site for a conventional system and require an alternative system designed
by a professional engineer.
C. Install a conventional system with increased trench spacing to compensate for clay.
D. Conduct a second percolation test after 30 days to confirm the rate.
Answer: B. Reject the site for a conventional system and require an alternative system
designed by a professional engineer.
Rationale: Kentucky regulations prohibit conventional systems in soils with percolation
rates slower than 60 min/in or with limiting layers that restrict effluent movement; smectitic
clay over fractured limestone poses a high risk of groundwater contamination and requires
an engineered alternative. Option A ignores the regulatory threshold and the limiting layer.
Option C does not address the fundamental unsuitability. Option D delays but does not
resolve the regulatory prohibition.
Page 1 of 84
,2. A proposed 4-bedroom home in Kentucky requires a septic system. Using the
Kentucky design flow of 120 gallons per bedroom per day and a soil application rate
of 0.4 gpd/ft², what is the minimum required absorption field area?
A. 800 ft²
B. 1,200 ft²
C. 1,600 ft²
D. 2,400 ft²
Answer: B. 1,200 ft²
Rationale: Design flow = 4 bedrooms × 120 gpd/bedroom = 480 gpd. Required area = 480
gpd ÷ 0.4 gpd/ft² = 1,200 ft². Options A, C, and D result from miscalculations or using
incorrect design flows or application rates.
Page 2 of 84
,3. An installer is preparing to install a septic tank in a area with a seasonal high water
table at 18 inches below the ground surface. Kentucky regulations require a minimum
separation of 24 inches between the bottom of the absorption field and the water table.
Which of the following is the most appropriate design modification?
A. Install a mounded system with the absorption field elevated above the natural grade.
B. Increase the size of the absorption field by 50% to compensate for the reduced
separation.
C. Install a curtain drain around the absorption field to lower the water table.
D. Use a concrete septic tank with a riser to the surface and proceed with a conventional
system.
Answer: A. Install a mounded system with the absorption field elevated above the
natural grade.
Rationale: A mounded system elevates the absorption field to achieve the required 24-inch
separation from the seasonal high water table, as allowed by Kentucky regulations. Option
B does not address the separation requirement. Option C may help but is not a guaranteed
solution and may not be approved without engineering. Option D does not resolve the
separation issue.
4. Which of the following best describes the primary function of a distribution box
(D-box) in a septic system absorption field?
A. To collect solids and prevent them from entering the absorption field.
B. To evenly distribute effluent to multiple drainfield lines.
C. To provide a means of measuring the volume of effluent entering the field.
D. To aerate the effluent before it enters the soil.
Answer: B. To evenly distribute effluent to multiple drainfield lines.
Rationale: A distribution box is designed to evenly distribute effluent to multiple drainfield
lines, ensuring uniform loading and preventing overloading of any single line. Option A
describes a septic tank's function. Option C is not a primary function. Option D is
incorrect; aeration occurs in aerobic treatment units.
Page 3 of 84
, 5. During an inspection of an existing septic system, an installer observes that the
effluent from the septic tank has a strong odor and contains significant solids. The
absorption field is not ponding. Which of the following is the most likely cause?
A. The septic tank is undersized for the home's occupancy.
B. The absorption field is failing and needs replacement.
C. The septic tank has not been pumped in over 10 years, leading to excessive sludge and
scum accumulation.
D. The distribution box is misaligned, causing uneven flow.
Answer: C. The septic tank has not been pumped in over 10 years, leading to excessive
sludge and scum accumulation.
Rationale: Excessive solids in the effluent indicate that the septic tank is not retaining
solids properly, often due to lack of maintenance and excessive sludge/scum buildup.
Option A could contribute but is less likely if the tank was properly sized originally. Option
B is not supported because the absorption field is not ponding. Option D would cause
uneven distribution, not solids carryover.
6. In Kentucky, which of the following is a requirement for the installation of a septic
system in a floodplain?
A. The system must be designed by a professional engineer and approved by the local
health department.
B. The system must be installed with a minimum 12-inch freeboard above the 100-year
flood elevation.
C. The system must be a mound system with a pump.
D. The system must be equipped with a backflow preventer on the outlet.
Answer: A. The system must be designed by a professional engineer and approved by
the local health department.
Rationale: Kentucky regulations require that septic systems in floodplains be designed by a
professional engineer and approved by the local health department to ensure protection of
public health and the environment. Options B, C, and D are not universal requirements and
may not be sufficient alone.
Page 4 of 84
