South Carolina Septic Tank Installer License Exam |
Practice Questions, Answers & Rationales 2026
Fast-track your South Carolina environmental certification with this premium study
bundle containing practice questions for the DHEC Septic Tank Installer License Exam.
Features comprehensive multiple-choice questions, verified answers, and detailed
regulations-based rationales covering soil classification, trench dimensions, setbacks,
and system configurations.
1. A Tier 2 installer license allows the holder to install all Tier 1 systems in addition
to which of the following?
A. Only gravity-fed residential systems
B. Standard 610 Specialized Onsite Wastewater Systems
C. Systems that require pumps, grease traps, and mounded systems
D. Only commercial systems exceeding 1,500 gallons per day
Answer: C. Systems that require pumps, grease traps, and mounded systems
Rationale: Tier 2 installers can install all Tier 1 systems plus systems requiring pumps,
grease traps, curtain drains, elevated infiltration systems, mounded systems, and all
commercial systems.
2. What is the required continuing education unit (CEU) total for a Tier 3 installer
every two-year licensing period?
A. 8 hours
B. 12 hours
C. 18 hours
D. 24 hours
Answer: C. 18 hours
,Rationale: Per Regulation 61-56, the required CEUs for each Tier for every two-year
licensing period are: Tier 1: 8 hours, Tier 2: 12 hours, Tier 3: 18 hours.
3. What is the licensure fee for a Tier 3 installer in South Carolina?
A. $50
B. $100
C. $150
D. $200
Answer: D. $200
Rationale: The licensure and annual renewal fees for onsite wastewater system installers
are: Tier 1 – $100, Tier 2 – $100, Tier 3 – $200.
4. A Tier 3 installer license applicant from out of state must demonstrate how
many years of experience with no pending or prior disciplinary action?
A. 2 years
B. 3 years
C. 5 years
D. 10 years
Answer: C. 5 years
Rationale: An onsite wastewater system installer licensee from another state must provide
affidavits from the regulatory authority demonstrating five (5) years of experience with no
pending or prior disciplinary action.
5. If a licensed installer fails to pay their renewal fee and the license expires, what
must they do?
,A. Pay a late fee and continue working
B. Submit a written appeal to SCDES
C. Apply for a new license and meet all applicable requirements
D. Automatically drop to a lower tier
Answer: C. Apply for a new license and meet all applicable requirements
Rationale: An expired license shall not be renewed. Any person with an expired license
may apply for a new license and must meet all applicable requirements for a new license.
6. How many CEU hours can be rolled over to the next licensing period if an
installer completes more than the required amount?
A. 1 hour
B. 2 hours
C. 3 hours
D. 5 hours
Answer: C. 3 hours
Rationale: If any installer completes more than the required hours in a licensing period, as
many as three (3) hours can be rolled over and credited to the requirement for the next
licensing period.
7. What is the minimum vertical separation required between the deepest point of
effluent application and the zone of saturation when peak sewage flow does NOT
exceed 1,500 gallons per day?
A. 3 inches
B. 6 inches
C. 12 inches
D. 18 inches
Answer: B. 6 inches
, Rationale: Where the estimated peak sewage flow will not exceed 1,500 gpd, the minimum
vertical separation between the deepest point of effluent application and the zone of
saturation shall be at least six (6) inches.
8. What is the required setback distance between a septic system and a private
drinking water well?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
Answer: C. 75 feet
Rationale: Regulation 61-56 requires that no part of the system be within seventy-five (75)
linear feet of a private well.
9. What is the required setback distance between a septic system and a public
well?
A. 50 feet
B. 75 feet
C. 100 feet
D. 150 feet
Answer: C. 100 feet
Rationale: Regulation 61-56 requires that no part of the system be within one hundred
(100) linear feet of a public well.
10. A Tier 3 installer is required to maintain which of the following that is NOT
required for Tier 1 or Tier 2 installers?
Practice Questions, Answers & Rationales 2026
Fast-track your South Carolina environmental certification with this premium study
bundle containing practice questions for the DHEC Septic Tank Installer License Exam.
Features comprehensive multiple-choice questions, verified answers, and detailed
regulations-based rationales covering soil classification, trench dimensions, setbacks,
and system configurations.
1. A Tier 2 installer license allows the holder to install all Tier 1 systems in addition
to which of the following?
A. Only gravity-fed residential systems
B. Standard 610 Specialized Onsite Wastewater Systems
C. Systems that require pumps, grease traps, and mounded systems
D. Only commercial systems exceeding 1,500 gallons per day
Answer: C. Systems that require pumps, grease traps, and mounded systems
Rationale: Tier 2 installers can install all Tier 1 systems plus systems requiring pumps,
grease traps, curtain drains, elevated infiltration systems, mounded systems, and all
commercial systems.
2. What is the required continuing education unit (CEU) total for a Tier 3 installer
every two-year licensing period?
A. 8 hours
B. 12 hours
C. 18 hours
D. 24 hours
Answer: C. 18 hours
,Rationale: Per Regulation 61-56, the required CEUs for each Tier for every two-year
licensing period are: Tier 1: 8 hours, Tier 2: 12 hours, Tier 3: 18 hours.
3. What is the licensure fee for a Tier 3 installer in South Carolina?
A. $50
B. $100
C. $150
D. $200
Answer: D. $200
Rationale: The licensure and annual renewal fees for onsite wastewater system installers
are: Tier 1 – $100, Tier 2 – $100, Tier 3 – $200.
4. A Tier 3 installer license applicant from out of state must demonstrate how
many years of experience with no pending or prior disciplinary action?
A. 2 years
B. 3 years
C. 5 years
D. 10 years
Answer: C. 5 years
Rationale: An onsite wastewater system installer licensee from another state must provide
affidavits from the regulatory authority demonstrating five (5) years of experience with no
pending or prior disciplinary action.
5. If a licensed installer fails to pay their renewal fee and the license expires, what
must they do?
,A. Pay a late fee and continue working
B. Submit a written appeal to SCDES
C. Apply for a new license and meet all applicable requirements
D. Automatically drop to a lower tier
Answer: C. Apply for a new license and meet all applicable requirements
Rationale: An expired license shall not be renewed. Any person with an expired license
may apply for a new license and must meet all applicable requirements for a new license.
6. How many CEU hours can be rolled over to the next licensing period if an
installer completes more than the required amount?
A. 1 hour
B. 2 hours
C. 3 hours
D. 5 hours
Answer: C. 3 hours
Rationale: If any installer completes more than the required hours in a licensing period, as
many as three (3) hours can be rolled over and credited to the requirement for the next
licensing period.
7. What is the minimum vertical separation required between the deepest point of
effluent application and the zone of saturation when peak sewage flow does NOT
exceed 1,500 gallons per day?
A. 3 inches
B. 6 inches
C. 12 inches
D. 18 inches
Answer: B. 6 inches
, Rationale: Where the estimated peak sewage flow will not exceed 1,500 gpd, the minimum
vertical separation between the deepest point of effluent application and the zone of
saturation shall be at least six (6) inches.
8. What is the required setback distance between a septic system and a private
drinking water well?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
Answer: C. 75 feet
Rationale: Regulation 61-56 requires that no part of the system be within seventy-five (75)
linear feet of a private well.
9. What is the required setback distance between a septic system and a public
well?
A. 50 feet
B. 75 feet
C. 100 feet
D. 150 feet
Answer: C. 100 feet
Rationale: Regulation 61-56 requires that no part of the system be within one hundred
(100) linear feet of a public well.
10. A Tier 3 installer is required to maintain which of the following that is NOT
required for Tier 1 or Tier 2 installers?
